[PATCH 4.4 00/30] 4.4.74-stable review

[PATCH 4.4 00/30] 4.4.74-stable review

[Greg Kroah-Hartman]

This is the start of the stable review cycle for the 4.4.74 release.
There are 30 patches in this series, all will be posted as a response
to this one.  If anyone has any issues with these being applied, please
let me know.

Responses should be made by Wed Jun 21 15:20:21 UTC 2017.
Anything received after that time might be too late.

The whole patch series can be found in one patch at:
	kernel.org/pub/linux/kernel/v4.x/stable-review/patch-4.4.74-rc1.gz
or in the git tree and branch at:
  git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-4.4.y
and the diffstat can be found below.

thanks,

greg k-h

-------------
Pseudo-Shortlog of commits:

Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Linux 4.4.74-rc1

Hugh Dickins <hughd@google.com>
    mm: larger stack guard gap, between vmas

Thomas Gleixner <tglx@linutronix.de>
    alarmtimer: Rate limit periodic intervals

Paul Burton <paul.burton@imgtec.com>
    MIPS: Fix bnezc/jialc return address calculation

Shuah Khan <shuahkh@osg.samsung.com>
    usb: dwc3: exynos fix axius clock error path to do cleanup

Thomas Gleixner <tglx@linutronix.de>
    alarmtimer: Prevent overflow of relative timers

Heiner Kallweit <hkallweit1@gmail.com>
    genirq: Release resources in __setup_irq() error path

Yu Zhao <yuzhao@google.com>
    swap: cond_resched in swap_cgroup_prepare()

James Morse <james.morse@arm.com>
    mm/memory-failure.c: use compound_head() flags for huge pages

Alan Stern <stern@rowland.harvard.edu>
    USB: gadgetfs, dummy-hcd, net2280: fix locking for callbacks

Corentin Labbe <clabbe.montjoie@gmail.com>
    usb: xhci: ASMedia ASM1042A chipset need shorts TX quirk

Dan Carpenter <dan.carpenter@oracle.com>
    drivers/misc/c2port/c2port-duramar2150.c: checking for NULL instead of IS_ERR()

Chris Brandt <chris.brandt@renesas.com>
    usb: r8a66597-hcd: decrease timeout

Chris Brandt <chris.brandt@renesas.com>
    usb: r8a66597-hcd: select a different endpoint on timeout

Johan Hovold <johan@kernel.org>
    USB: gadget: dummy_hcd: fix hub-descriptor removable fields

Arnd Bergmann <arnd@arndb.de>
    pvrusb2: reduce stack usage pvr2_eeprom_analyze()

Anton Bondarenko <anton.bondarenko.sama@gmail.com>
    usb: core: fix potential memory leak in error path during hcd creation

Johan Hovold <johan@kernel.org>
    USB: hub: fix SS max number of ports

Matt Ranostay <matt.ranostay@konsulko.com>
    iio: proximity: as3935: recalibrate RCO after resume

Dan Carpenter <dan.carpenter@oracle.com>
    staging: rtl8188eu: prevent an underflow in rtw_check_beacon_data()

Tony Lindgren <tony@atomide.com>
    mfd: omap-usb-tll: Fix inverted bit use for USB TLL mode

Laura Abbott <labbott@redhat.com>
    x86/mm/32: Set the '__vmalloc_start_set' flag in initmem_init()

Christophe JAILLET <christophe.jaillet@wanadoo.fr>
    serial: efm32: Fix parity management in 'efm32_uart_console_get_options()'

Johannes Berg <johannes.berg@intel.com>
    mac80211: fix IBSS presp allocation size

Koen Vandeputte <koen.vandeputte@ncentric.com>
    mac80211: fix CSA in IBSS mode

Jason A. Donenfeld <Jason@zx2c4.com>
    mac80211/wpa: use constant time memory comparison for MACs

Emmanuel Grumbach <emmanuel.grumbach@intel.com>
    mac80211: don't look at the PM bit of BAR frames

Christophe JAILLET <christophe.jaillet@wanadoo.fr>
    vb2: Fix an off by one error in 'vb2_plane_vaddr'

Tomasz Wilczyński <twilczynski@naver.com>
    cpufreq: conservative: Allow down_threshold to take values from 1 to 10

Marc Kleine-Budde <mkl@pengutronix.de>
    can: gs_usb: fix memory leak in gs_cmd_reset()

Nicholas Bellinger <nab@linux-iscsi.org>
    configfs: Fix race between create_link and configfs_rmdir


-------------

Diffstat:

 Documentation/kernel-parameters.txt        |   7 ++
 Makefile                                   |   4 +-
 arch/arc/mm/mmap.c                         |   2 +-
 arch/arm/mm/mmap.c                         |   4 +-
 arch/frv/mm/elf-fdpic.c                    |   2 +-
 arch/mips/kernel/branch.c                  |   4 +-
 arch/mips/mm/mmap.c                        |   2 +-
 arch/parisc/kernel/sys_parisc.c            |  15 +--
 arch/powerpc/mm/slice.c                    |   2 +-
 arch/s390/mm/mmap.c                        |   4 +-
 arch/sh/mm/mmap.c                          |   4 +-
 arch/sparc/kernel/sys_sparc_64.c           |   4 +-
 arch/sparc/mm/hugetlbpage.c                |   2 +-
 arch/tile/mm/hugetlbpage.c                 |   2 +-
 arch/x86/kernel/sys_x86_64.c               |   4 +-
 arch/x86/mm/hugetlbpage.c                  |   2 +-
 arch/x86/mm/numa_32.c                      |   1 +
 arch/xtensa/kernel/syscall.c               |   2 +-
 drivers/cpufreq/cpufreq_conservative.c     |   4 +-
 drivers/iio/proximity/as3935.c             |   6 +-
 drivers/media/usb/pvrusb2/pvrusb2-eeprom.c |  13 +--
 drivers/media/v4l2-core/videobuf2-core.c   |   2 +-
 drivers/mfd/omap-usb-tll.c                 |   2 +-
 drivers/misc/c2port/c2port-duramar2150.c   |   4 +-
 drivers/net/can/usb/gs_usb.c               |   2 +
 drivers/staging/rtl8188eu/core/rtw_ap.c    |   2 +-
 drivers/tty/serial/efm32-uart.c            |  11 ++-
 drivers/usb/core/hcd.c                     |   1 +
 drivers/usb/core/hub.c                     |   8 +-
 drivers/usb/dwc3/dwc3-exynos.c             |   4 +-
 drivers/usb/gadget/legacy/inode.c          |   5 +-
 drivers/usb/gadget/udc/dummy_hcd.c         |  19 ++--
 drivers/usb/gadget/udc/net2280.c           |   9 +-
 drivers/usb/host/r8a66597-hcd.c            |   6 +-
 drivers/usb/host/xhci-pci.c                |   3 +
 fs/configfs/symlink.c                      |   3 +-
 fs/hugetlbfs/inode.c                       |   2 +-
 fs/proc/task_mmu.c                         |   4 -
 include/linux/mm.h                         |  55 +++++------
 include/uapi/linux/usb/ch11.h              |   3 +
 kernel/irq/manage.c                        |   4 +-
 kernel/time/alarmtimer.c                   |  14 ++-
 mm/gup.c                                   |   5 -
 mm/memory-failure.c                        |   5 +-
 mm/memory.c                                |  38 --------
 mm/mmap.c                                  | 147 +++++++++++++++++------------
 mm/swap_cgroup.c                           |   3 +
 net/mac80211/ibss.c                        |   6 +-
 net/mac80211/rx.c                          |   6 +-
 net/mac80211/wpa.c                         |   9 +-
 50 files changed, 245 insertions(+), 227 deletions(-)

[PATCH 4.4 01/30] configfs: Fix race between create_link and configfs_rmdir

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Nicholas Bellinger <nab@linux-iscsi.org>

commit ba80aa909c99802c428682c352b0ee0baac0acd3 upstream.

This patch closes a long standing race in configfs between
the creation of a new symlink in create_link(), while the
symlink target's config_item is being concurrently removed
via configfs_rmdir().

This can happen because the symlink target's reference
is obtained by config_item_get() in create_link() before
the CONFIGFS_USET_DROPPING bit set by configfs_detach_prep()
during configfs_rmdir() shutdown is actually checked..

This originally manifested itself on ppc64 on v4.8.y under
heavy load using ibmvscsi target ports with Novalink API:

[ 7877.289863] rpadlpar_io: slot U8247.22L.212A91A-V1-C8 added
[ 7879.893760] ------------[ cut here ]------------
[ 7879.893768] WARNING: CPU: 15 PID: 17585 at ./include/linux/kref.h:46 config_item_get+0x7c/0x90 [configfs]
[ 7879.893811] CPU: 15 PID: 17585 Comm: targetcli Tainted: G           O 4.8.17-customv2.22 #12
[ 7879.893812] task: c00000018a0d3400 task.stack: c0000001f3b40000
[ 7879.893813] NIP: d000000002c664ec LR: d000000002c60980 CTR: c000000000b70870
[ 7879.893814] REGS: c0000001f3b43810 TRAP: 0700   Tainted: G O     (4.8.17-customv2.22)
[ 7879.893815] MSR: 8000000000029033 <SF,EE,ME,IR,DR,RI,LE>  CR: 28222242  XER: 00000000
[ 7879.893820] CFAR: d000000002c664bc SOFTE: 1
                GPR00: d000000002c60980 c0000001f3b43a90 d000000002c70908 c0000000fbc06820
                GPR04: c0000001ef1bd900 0000000000000004 0000000000000001 0000000000000000
                GPR08: 0000000000000000 0000000000000001 d000000002c69560 d000000002c66d80
                GPR12: c000000000b70870 c00000000e798700 c0000001f3b43ca0 c0000001d4949d40
                GPR16: c00000014637e1c0 0000000000000000 0000000000000000 c0000000f2392940
                GPR20: c0000001f3b43b98 0000000000000041 0000000000600000 0000000000000000
                GPR24: fffffffffffff000 0000000000000000 d000000002c60be0 c0000001f1dac490
                GPR28: 0000000000000004 0000000000000000 c0000001ef1bd900 c0000000f2392940
[ 7879.893839] NIP [d000000002c664ec] config_item_get+0x7c/0x90 [configfs]
[ 7879.893841] LR [d000000002c60980] check_perm+0x80/0x2e0 [configfs]
[ 7879.893842] Call Trace:
[ 7879.893844] [c0000001f3b43ac0] [d000000002c60980] check_perm+0x80/0x2e0 [configfs]
[ 7879.893847] [c0000001f3b43b10] [c000000000329770] do_dentry_open+0x2c0/0x460
[ 7879.893849] [c0000001f3b43b70] [c000000000344480] path_openat+0x210/0x1490
[ 7879.893851] [c0000001f3b43c80] [c00000000034708c] do_filp_open+0xfc/0x170
[ 7879.893853] [c0000001f3b43db0] [c00000000032b5bc] do_sys_open+0x1cc/0x390
[ 7879.893856] [c0000001f3b43e30] [c000000000009584] system_call+0x38/0xec
[ 7879.893856] Instruction dump:
[ 7879.893858] 409d0014 38210030 e8010010 7c0803a6 4e800020 3d220000 e94981e0 892a0000
[ 7879.893861] 2f890000 409effe0 39200001 992a0000 <0fe00000> 4bffffd0 60000000 60000000
[ 7879.893866] ---[ end trace 14078f0b3b5ad0aa ]---

To close this race, go ahead and obtain the symlink's target
config_item reference only after the existing CONFIGFS_USET_DROPPING
check succeeds.

This way, if configfs_rmdir() wins create_link() will return -ENONET,
and if create_link() wins configfs_rmdir() will return -EBUSY.

Reported-by: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
Tested-by: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/configfs/symlink.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

--- a/fs/configfs/symlink.c
+++ b/fs/configfs/symlink.c
@@ -83,14 +83,13 @@ static int create_link(struct config_ite
 	ret = -ENOMEM;
 	sl = kmalloc(sizeof(struct configfs_symlink), GFP_KERNEL);
 	if (sl) {
-		sl->sl_target = config_item_get(item);
 		spin_lock(&configfs_dirent_lock);
 		if (target_sd->s_type & CONFIGFS_USET_DROPPING) {
 			spin_unlock(&configfs_dirent_lock);
-			config_item_put(item);
 			kfree(sl);
 			return -ENOENT;
 		}
+		sl->sl_target = config_item_get(item);
 		list_add(&sl->sl_list, &target_sd->s_links);
 		spin_unlock(&configfs_dirent_lock);
 		ret = configfs_create_link(sl, parent_item->ci_dentry,

[PATCH 4.4 02/30] can: gs_usb: fix memory leak in gs_cmd_reset()

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Marc Kleine-Budde <mkl@pengutronix.de>

commit 5cda3ee5138e91ac369ed9d0b55eab0dab077686 upstream.

This patch adds the missing kfree() in gs_cmd_reset() to free the
memory that is not used anymore after usb_control_msg().

Cc: Maximilian Schneider <max@schneidersoft.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/net/can/usb/gs_usb.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/net/can/usb/gs_usb.c
+++ b/drivers/net/can/usb/gs_usb.c
@@ -246,6 +246,8 @@ static int gs_cmd_reset(struct gs_usb *g
 			     sizeof(*dm),
 			     1000);
 
+	kfree(dm);
+
 	return rc;
 }
 

[PATCH 4.4 04/30] [media] vb2: Fix an off by one error in vb2_plane_vaddr

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Christophe JAILLET <christophe.jaillet@wanadoo.fr>

commit 5ebb6dd36c9f5fb37b1077b393c254d70a14cb46 upstream.

We should ensure that 'plane_no' is '< vb->num_planes' as done in
'vb2_plane_cookie' just a few lines below.

Fixes: e23ccc0ad925 ("[media] v4l: add videobuf2 Video for Linux 2 driver framework")

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/media/v4l2-core/videobuf2-core.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/media/v4l2-core/videobuf2-core.c
+++ b/drivers/media/v4l2-core/videobuf2-core.c
@@ -793,7 +793,7 @@ EXPORT_SYMBOL_GPL(vb2_core_create_bufs);
  */
 void *vb2_plane_vaddr(struct vb2_buffer *vb, unsigned int plane_no)
 {
-	if (plane_no > vb->num_planes || !vb->planes[plane_no].mem_priv)
+	if (plane_no >= vb->num_planes || !vb->planes[plane_no].mem_priv)
 		return NULL;
 
 	return call_ptr_memop(vb, vaddr, vb->planes[plane_no].mem_priv);

[PATCH 4.4 05/30] mac80211: dont look at the PM bit of BAR frames

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

commit 769dc04db3ed8484798aceb015b94deacc2ba557 upstream.

When a peer sends a BAR frame with PM bit clear, we should
not modify its PM state as madated by the spec in
802.11-20012 10.2.1.2.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 net/mac80211/rx.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -1455,12 +1455,16 @@ ieee80211_rx_h_sta_process(struct ieee80
 	 */
 	if (!ieee80211_hw_check(&sta->local->hw, AP_LINK_PS) &&
 	    !ieee80211_has_morefrags(hdr->frame_control) &&
+	    !ieee80211_is_back_req(hdr->frame_control) &&
 	    !(status->rx_flags & IEEE80211_RX_DEFERRED_RELEASE) &&
 	    (rx->sdata->vif.type == NL80211_IFTYPE_AP ||
 	     rx->sdata->vif.type == NL80211_IFTYPE_AP_VLAN) &&
-	    /* PM bit is only checked in frames where it isn't reserved,
+	    /*
+	     * PM bit is only checked in frames where it isn't reserved,
 	     * in AP mode it's reserved in non-bufferable management frames
 	     * (cf. IEEE 802.11-2012 8.2.4.1.7 Power Management field)
+	     * BAR frames should be ignored as specified in
+	     * IEEE 802.11-2012 10.2.1.2.
 	     */
 	    (!ieee80211_is_mgmt(hdr->frame_control) ||
 	     ieee80211_is_bufferable_mmpdu(hdr->frame_control))) {

[PATCH 4.4 06/30] mac80211/wpa: use constant time memory comparison for MACs

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jason A. Donenfeld <Jason@zx2c4.com>

commit 98c67d187db7808b1f3c95f2110dd4392d034182 upstream.

Otherwise, we enable all sorts of forgeries via timing attack.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: linux-wireless@vger.kernel.org
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 net/mac80211/wpa.c |    9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

--- a/net/mac80211/wpa.c
+++ b/net/mac80211/wpa.c
@@ -16,6 +16,7 @@
 #include <asm/unaligned.h>
 #include <net/mac80211.h>
 #include <crypto/aes.h>
+#include <crypto/algapi.h>
 
 #include "ieee80211_i.h"
 #include "michael.h"
@@ -152,7 +153,7 @@ ieee80211_rx_h_michael_mic_verify(struct
 	data_len = skb->len - hdrlen - MICHAEL_MIC_LEN;
 	key = &rx->key->conf.key[NL80211_TKIP_DATA_OFFSET_RX_MIC_KEY];
 	michael_mic(key, hdr, data, data_len, mic);
-	if (memcmp(mic, data + data_len, MICHAEL_MIC_LEN) != 0)
+	if (crypto_memneq(mic, data + data_len, MICHAEL_MIC_LEN))
 		goto mic_fail;
 
 	/* remove Michael MIC from payload */
@@ -1044,7 +1045,7 @@ ieee80211_crypto_aes_cmac_decrypt(struct
 		bip_aad(skb, aad);
 		ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad,
 				   skb->data + 24, skb->len - 24, mic);
-		if (memcmp(mic, mmie->mic, sizeof(mmie->mic)) != 0) {
+		if (crypto_memneq(mic, mmie->mic, sizeof(mmie->mic))) {
 			key->u.aes_cmac.icverrors++;
 			return RX_DROP_UNUSABLE;
 		}
@@ -1094,7 +1095,7 @@ ieee80211_crypto_aes_cmac_256_decrypt(st
 		bip_aad(skb, aad);
 		ieee80211_aes_cmac_256(key->u.aes_cmac.tfm, aad,
 				       skb->data + 24, skb->len - 24, mic);
-		if (memcmp(mic, mmie->mic, sizeof(mmie->mic)) != 0) {
+		if (crypto_memneq(mic, mmie->mic, sizeof(mmie->mic))) {
 			key->u.aes_cmac.icverrors++;
 			return RX_DROP_UNUSABLE;
 		}
@@ -1198,7 +1199,7 @@ ieee80211_crypto_aes_gmac_decrypt(struct
 		if (ieee80211_aes_gmac(key->u.aes_gmac.tfm, aad, nonce,
 				       skb->data + 24, skb->len - 24,
 				       mic) < 0 ||
-		    memcmp(mic, mmie->mic, sizeof(mmie->mic)) != 0) {
+		    crypto_memneq(mic, mmie->mic, sizeof(mmie->mic))) {
 			key->u.aes_gmac.icverrors++;
 			return RX_DROP_UNUSABLE;
 		}

[PATCH 4.4 08/30] mac80211: fix IBSS presp allocation size

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Johannes Berg <johannes.berg@intel.com>

commit f1f3e9e2a50a70de908f9dfe0d870e9cdc67e042 upstream.

When VHT IBSS support was added, the size of the extra elements
wasn't considered in ieee80211_ibss_build_presp(), which makes
it possible that it would overrun the allocated buffer. Fix it
by allocating the necessary space.

Fixes: abcff6ef01f9 ("mac80211: add VHT support for IBSS")
Reported-by: Shaul Triebitz <shaul.triebitz@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 net/mac80211/ibss.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/net/mac80211/ibss.c
+++ b/net/mac80211/ibss.c
@@ -66,6 +66,8 @@ ieee80211_ibss_build_presp(struct ieee80
 		    2 + (IEEE80211_MAX_SUPP_RATES - 8) +
 		    2 + sizeof(struct ieee80211_ht_cap) +
 		    2 + sizeof(struct ieee80211_ht_operation) +
+		    2 + sizeof(struct ieee80211_vht_cap) +
+		    2 + sizeof(struct ieee80211_vht_operation) +
 		    ifibss->ie_len;
 	presp = kzalloc(sizeof(*presp) + frame_len, GFP_KERNEL);
 	if (!presp)

[PATCH 4.4 10/30] x86/mm/32: Set the __vmalloc_start_set flag in initmem_init()

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Laura Abbott <labbott@redhat.com>

commit 861ce4a3244c21b0af64f880d5bfe5e6e2fb9e4a upstream.

'__vmalloc_start_set' currently only gets set in initmem_init() when
!CONFIG_NEED_MULTIPLE_NODES. This breaks detection of vmalloc address
with virt_addr_valid() with CONFIG_NEED_MULTIPLE_NODES=y, causing
a kernel crash:

  [mm/usercopy] 517e1fbeb6: kernel BUG at arch/x86/mm/physaddr.c:78!

Set '__vmalloc_start_set' appropriately for that case as well.

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Laura Abbott <labbott@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: dc16ecf7fd1f ("x86-32: use specific __vmalloc_start_set flag in __virt_addr_valid")
Link: http://lkml.kernel.org/r/1494278596-30373-1-git-send-email-labbott@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/x86/mm/numa_32.c |    1 +
 1 file changed, 1 insertion(+)

--- a/arch/x86/mm/numa_32.c
+++ b/arch/x86/mm/numa_32.c
@@ -100,5 +100,6 @@ void __init initmem_init(void)
 	printk(KERN_DEBUG "High memory starts at vaddr %08lx\n",
 			(ulong) pfn_to_kaddr(highstart_pfn));
 
+	__vmalloc_start_set = true;
 	setup_bootmem_allocator();
 }

[PATCH 4.4 11/30] mfd: omap-usb-tll: Fix inverted bit use for USB TLL mode

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Tony Lindgren <tony@atomide.com>

commit 8b8a84c54aff4256d592dc18346c65ecf6811b45 upstream.

Commit 16fa3dc75c22 ("mfd: omap-usb-tll: HOST TLL platform driver")
added support for USB TLL, but uses OMAP_TLL_CHANNEL_CONF_ULPINOBITSTUFF
bit the wrong way. The comments in the code are correct, but the inverted
use of OMAP_TLL_CHANNEL_CONF_ULPINOBITSTUFF causes the register to be
enabled instead of disabled unlike what the comments say.

Without this change the Wrigley 3G LTE modem on droid 4 EHCI bus can
be only pinged few times before it stops responding.

Fixes: 16fa3dc75c22 ("mfd: omap-usb-tll: HOST TLL platform driver")
Signed-off-by: Tony Lindgren <tony@atomide.com>
Acked-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/mfd/omap-usb-tll.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/mfd/omap-usb-tll.c
+++ b/drivers/mfd/omap-usb-tll.c
@@ -375,8 +375,8 @@ int omap_tll_init(struct usbhs_omap_plat
 				 * and use SDR Mode
 				 */
 				reg &= ~(OMAP_TLL_CHANNEL_CONF_UTMIAUTOIDLE
-					| OMAP_TLL_CHANNEL_CONF_ULPINOBITSTUFF
 					| OMAP_TLL_CHANNEL_CONF_ULPIDDRMODE);
+				reg |= OMAP_TLL_CHANNEL_CONF_ULPINOBITSTUFF;
 			} else if (pdata->port_mode[i] ==
 					OMAP_EHCI_PORT_MODE_HSIC) {
 				/*

[PATCH 4.4 12/30] staging: rtl8188eu: prevent an underflow in rtw_check_beacon_data()

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Dan Carpenter <dan.carpenter@oracle.com>

commit 784047eb2d3405a35087af70cba46170c5576b25 upstream.

The "len" could be as low as -14 so we should check for negatives.

Fixes: 9a7fe54ddc3a ("staging: r8188eu: Add source files for new driver - part 1")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/staging/rtl8188eu/core/rtw_ap.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/staging/rtl8188eu/core/rtw_ap.c
+++ b/drivers/staging/rtl8188eu/core/rtw_ap.c
@@ -894,7 +894,7 @@ int rtw_check_beacon_data(struct adapter
 		return _FAIL;
 
 
-	if (len > MAX_IE_SZ)
+	if (len < 0 || len > MAX_IE_SZ)
 		return _FAIL;
 
 	pbss_network->IELength = len;

[PATCH 4.4 13/30] iio: proximity: as3935: recalibrate RCO after resume

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Matt Ranostay <matt.ranostay@konsulko.com>

commit 6272c0de13abf1480f701d38288f28a11b4301c4 upstream.

According to the datasheet the RCO must be recalibrated
on every power-on-reset. Also remove mutex locking in the
calibration function since callers other than the probe
function (which doesn't need it) will have a lock.

Fixes: 24ddb0e4bba4 ("iio: Add AS3935 lightning sensor support")
Cc: George McCollister <george.mccollister@gmail.com>
Signed-off-by: Matt Ranostay <matt.ranostay@konsulko.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/iio/proximity/as3935.c |    6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

--- a/drivers/iio/proximity/as3935.c
+++ b/drivers/iio/proximity/as3935.c
@@ -263,8 +263,6 @@ static irqreturn_t as3935_interrupt_hand
 
 static void calibrate_as3935(struct as3935_state *st)
 {
-	mutex_lock(&st->lock);
-
 	/* mask disturber interrupt bit */
 	as3935_write(st, AS3935_INT, BIT(5));
 
@@ -274,8 +272,6 @@ static void calibrate_as3935(struct as39
 
 	mdelay(2);
 	as3935_write(st, AS3935_TUNE_CAP, (st->tune_cap / TUNE_CAP_DIV));
-
-	mutex_unlock(&st->lock);
 }
 
 #ifdef CONFIG_PM_SLEEP
@@ -312,6 +308,8 @@ static int as3935_resume(struct device *
 	val &= ~AS3935_AFE_PWR_BIT;
 	ret = as3935_write(st, AS3935_AFE_GAIN, val);
 
+	calibrate_as3935(st);
+
 err_resume:
 	mutex_unlock(&st->lock);
 

[PATCH 4.4 14/30] USB: hub: fix SS max number of ports

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Johan Hovold <johan@kernel.org>

commit 93491ced3c87c94b12220dbac0527e1356702179 upstream.

Add define for the maximum number of ports on a SuperSpeed hub as per
USB 3.1 spec Table 10-5, and use it when verifying the retrieved hub
descriptor.

This specifically avoids benign attempts to update the DeviceRemovable
mask for non-existing ports (should we get that far).

Fixes: dbe79bbe9dcb ("USB 3.0 Hub Changes")
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/usb/core/hub.c        |    8 +++++++-
 include/uapi/linux/usb/ch11.h |    3 +++
 2 files changed, 10 insertions(+), 1 deletion(-)

--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1318,7 +1318,13 @@ static int hub_configure(struct usb_hub
 	if (ret < 0) {
 		message = "can't read hub descriptor";
 		goto fail;
-	} else if (hub->descriptor->bNbrPorts > USB_MAXCHILDREN) {
+	}
+
+	maxchild = USB_MAXCHILDREN;
+	if (hub_is_superspeed(hdev))
+		maxchild = min_t(unsigned, maxchild, USB_SS_MAXPORTS);
+
+	if (hub->descriptor->bNbrPorts > maxchild) {
 		message = "hub has too many ports!";
 		ret = -ENODEV;
 		goto fail;
--- a/include/uapi/linux/usb/ch11.h
+++ b/include/uapi/linux/usb/ch11.h
@@ -22,6 +22,9 @@
  */
 #define USB_MAXCHILDREN		31
 
+/* See USB 3.1 spec Table 10-5 */
+#define USB_SS_MAXPORTS		15
+
 /*
  * Hub request types
  */

[PATCH 4.4 15/30] usb: core: fix potential memory leak in error path during hcd creation

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Anton Bondarenko <anton.bondarenko.sama@gmail.com>

commit 1a744d2eb76aaafb997fda004ae3ae62a1538f85 upstream.

Free memory allocated for address0_mutex if allocation of bandwidth_mutex
failed.

Fixes: feb26ac31a2a ("usb: core: hub: hub_port_init lock controller instead of bus")

Signed-off-by: Anton Bondarenko <anton.bondarenko.sama@gmail.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/usb/core/hcd.c |    1 +
 1 file changed, 1 insertion(+)

--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -2511,6 +2511,7 @@ struct usb_hcd *usb_create_shared_hcd(co
 		hcd->bandwidth_mutex = kmalloc(sizeof(*hcd->bandwidth_mutex),
 				GFP_KERNEL);
 		if (!hcd->bandwidth_mutex) {
+			kfree(hcd->address0_mutex);
 			kfree(hcd);
 			dev_dbg(dev, "hcd bandwidth mutex alloc failed\n");
 			return NULL;

[PATCH 4.4 16/30] [media] pvrusb2: reduce stack usage pvr2_eeprom_analyze()

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Arnd Bergmann <arnd@arndb.de>

commit 6830733d53a4517588e56227b9c8538633f0c496 upstream.

The driver uses a relatively large data structure on the stack, which
showed up on my radar as we get a warning with the "latent entropy"
GCC plugin:

drivers/media/usb/pvrusb2/pvrusb2-eeprom.c:153:1: error: the frame size of 1376 bytes is larger than 1152 bytes [-Werror=frame-larger-than=]

The warning is usually hidden as we raise the warning limit to 2048
when the plugin is enabled, but I'd like to lower that again in the
future, and making this function smaller helps to do that without
build regressions.

Further analysis shows that putting an 'i2c_client' structure on
the stack is not really supported, as the embedded 'struct device'
is not initialized here, and we are only saved by the fact that
the function that is called here does not use the pointer at all.

Fixes: d855497edbfb ("V4L/DVB (4228a): pvrusb2 to kernel 2.6.18")

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/media/usb/pvrusb2/pvrusb2-eeprom.c |   11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

--- a/drivers/media/usb/pvrusb2/pvrusb2-eeprom.c
+++ b/drivers/media/usb/pvrusb2/pvrusb2-eeprom.c
@@ -123,15 +123,10 @@ int pvr2_eeprom_analyze(struct pvr2_hdw
 	memset(&tvdata,0,sizeof(tvdata));
 
 	eeprom = pvr2_eeprom_fetch(hdw);
-	if (!eeprom) return -EINVAL;
+	if (!eeprom)
+		return -EINVAL;
 
-	{
-		struct i2c_client fake_client;
-		/* Newer version expects a useless client interface */
-		fake_client.addr = hdw->eeprom_addr;
-		fake_client.adapter = &hdw->i2c_adap;
-		tveeprom_hauppauge_analog(&fake_client,&tvdata,eeprom);
-	}
+	tveeprom_hauppauge_analog(NULL, &tvdata, eeprom);
 
 	trace_eeprom("eeprom assumed v4l tveeprom module");
 	trace_eeprom("eeprom direct call results:");

[PATCH 4.4 17/30] USB: gadget: dummy_hcd: fix hub-descriptor removable fields

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Johan Hovold <johan@kernel.org>

commit d81182ce30dbd497a1e7047d7fda2af040347790 upstream.

Flag the first and only port as removable while also leaving the
remaining bits (including the reserved bit zero) unset in accordance
with the specifications:

	"Within a byte, if no port exists for a given location, the bit
	field representing the port characteristics shall be 0."

Also add a comment marking the legacy PortPwrCtrlMask field.

Fixes: 1cd8fd2887e1 ("usb: gadget: dummy_hcd: add SuperSpeed support")
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: Tatyana Brokhman <tlinder@codeaurora.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/usb/gadget/udc/dummy_hcd.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/drivers/usb/gadget/udc/dummy_hcd.c
+++ b/drivers/usb/gadget/udc/dummy_hcd.c
@@ -2011,7 +2011,7 @@ ss_hub_descriptor(struct usb_hub_descrip
 			HUB_CHAR_COMMON_OCPM);
 	desc->bNbrPorts = 1;
 	desc->u.ss.bHubHdrDecLat = 0x04; /* Worst case: 0.4 micro sec*/
-	desc->u.ss.DeviceRemovable = 0xffff;
+	desc->u.ss.DeviceRemovable = 0;
 }
 
 static inline void hub_descriptor(struct usb_hub_descriptor *desc)
@@ -2023,8 +2023,8 @@ static inline void hub_descriptor(struct
 			HUB_CHAR_INDV_PORT_LPSM |
 			HUB_CHAR_COMMON_OCPM);
 	desc->bNbrPorts = 1;
-	desc->u.hs.DeviceRemovable[0] = 0xff;
-	desc->u.hs.DeviceRemovable[1] = 0xff;
+	desc->u.hs.DeviceRemovable[0] = 0;
+	desc->u.hs.DeviceRemovable[1] = 0xff;	/* PortPwrCtrlMask */
 }
 
 static int dummy_hub_control(

[PATCH 4.4 18/30] usb: r8a66597-hcd: select a different endpoint on timeout

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Chris Brandt <chris.brandt@renesas.com>

commit 1f873d857b6c2fefb4dada952674aa01bcfb92bd upstream.

If multiple endpoints on a single device have pending IN URBs and one
endpoint times out due to NAKs (perfectly legal), select a different
endpoint URB to try.
The existing code only checked to see another device address has pending
URBs and ignores other IN endpoints on the current device address. This
leads to endpoints never getting serviced if one endpoint is using NAK as
a flow control method.

Fixes: 5d3043586db4 ("usb: r8a66597-hcd: host controller driver for R8A6659")
Signed-off-by: Chris Brandt <chris.brandt@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/usb/host/r8a66597-hcd.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/usb/host/r8a66597-hcd.c
+++ b/drivers/usb/host/r8a66597-hcd.c
@@ -1785,6 +1785,7 @@ static void r8a66597_td_timer(unsigned l
 		pipe = td->pipe;
 		pipe_stop(r8a66597, pipe);
 
+		/* Select a different address or endpoint */
 		new_td = td;
 		do {
 			list_move_tail(&new_td->queue,
@@ -1794,7 +1795,8 @@ static void r8a66597_td_timer(unsigned l
 				new_td = td;
 				break;
 			}
-		} while (td != new_td && td->address == new_td->address);
+		} while (td != new_td && td->address == new_td->address &&
+			td->pipe->info.epnum == new_td->pipe->info.epnum);
 
 		start_transfer(r8a66597, new_td);
 

[PATCH 4.4 19/30] usb: r8a66597-hcd: decrease timeout

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Chris Brandt <chris.brandt@renesas.com>

commit dd14a3e9b92ac6f0918054f9e3477438760a4fa6 upstream.

The timeout for BULK packets was 300ms which is a long time if other
endpoints or devices are waiting for their turn. Changing it to 50ms
greatly increased the overall performance for multi-endpoint devices.

Fixes: 5d3043586db4 ("usb: r8a66597-hcd: host controller driver for R8A6659")
Signed-off-by: Chris Brandt <chris.brandt@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/usb/host/r8a66597-hcd.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/usb/host/r8a66597-hcd.c
+++ b/drivers/usb/host/r8a66597-hcd.c
@@ -1269,7 +1269,7 @@ static void set_td_timer(struct r8a66597
 			time = 30;
 			break;
 		default:
-			time = 300;
+			time = 50;
 			break;
 		}
 

[PATCH 4.4 20/30] drivers/misc/c2port/c2port-duramar2150.c: checking for NULL instead of IS_ERR()

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Dan Carpenter <dan.carpenter@oracle.com>

commit 8128a31eaadbcdfa37774bbd28f3f00bac69996a upstream.

c2port_device_register() never returns NULL, it uses error pointers.

Link: http://lkml.kernel.org/r/20170412083321.GC3250@mwanda
Fixes: 65131cd52b9e ("c2port: add c2port support for Eurotech Duramar 2150")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Rodolfo Giometti <giometti@linux.it>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/misc/c2port/c2port-duramar2150.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/misc/c2port/c2port-duramar2150.c
+++ b/drivers/misc/c2port/c2port-duramar2150.c
@@ -129,8 +129,8 @@ static int __init duramar2150_c2port_ini
 
 	duramar2150_c2port_dev = c2port_device_register("uc",
 					&duramar2150_c2port_ops, NULL);
-	if (!duramar2150_c2port_dev) {
-		ret = -ENODEV;
+	if (IS_ERR(duramar2150_c2port_dev)) {
+		ret = PTR_ERR(duramar2150_c2port_dev);
 		goto free_region;
 	}
 

[PATCH 4.4 21/30] usb: xhci: ASMedia ASM1042A chipset need shorts TX quirk

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Corentin Labbe <clabbe.montjoie@gmail.com>

commit d2f48f05cd2a2a0a708fbfa45f1a00a87660d937 upstream.

When plugging an USB webcam I see the following message:
[106385.615559] xhci_hcd 0000:04:00.0: WARN Successful completion on short TX: needs XHCI_TRUST_TX_LENGTH quirk?
[106390.583860] handle_tx_event: 913 callbacks suppressed

With this patch applied, I get no more printing of this message.

Signed-off-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/usb/host/xhci-pci.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -198,6 +198,9 @@ static void xhci_pci_quirks(struct devic
 	if (pdev->vendor == PCI_VENDOR_ID_ASMEDIA &&
 			pdev->device == 0x1042)
 		xhci->quirks |= XHCI_BROKEN_STREAMS;
+	if (pdev->vendor == PCI_VENDOR_ID_ASMEDIA &&
+			pdev->device == 0x1142)
+		xhci->quirks |= XHCI_TRUST_TX_LENGTH;
 
 	if (xhci->quirks & XHCI_RESET_ON_RESUME)
 		xhci_dbg_trace(xhci, trace_xhci_dbg_quirks,

[PATCH 4.4 22/30] USB: gadgetfs, dummy-hcd, net2280: fix locking for callbacks

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Alan Stern <stern@rowland.harvard.edu>

commit f16443a034c7aa359ddf6f0f9bc40d01ca31faea upstream.

Using the syzkaller kernel fuzzer, Andrey Konovalov generated the
following error in gadgetfs:

> BUG: KASAN: use-after-free in __lock_acquire+0x3069/0x3690
> kernel/locking/lockdep.c:3246
> Read of size 8 at addr ffff88003a2bdaf8 by task kworker/3:1/903
>
> CPU: 3 PID: 903 Comm: kworker/3:1 Not tainted 4.12.0-rc4+ #35
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
> Workqueue: usb_hub_wq hub_event
> Call Trace:
>  __dump_stack lib/dump_stack.c:16 [inline]
>  dump_stack+0x292/0x395 lib/dump_stack.c:52
>  print_address_description+0x78/0x280 mm/kasan/report.c:252
>  kasan_report_error mm/kasan/report.c:351 [inline]
>  kasan_report+0x230/0x340 mm/kasan/report.c:408
>  __asan_report_load8_noabort+0x19/0x20 mm/kasan/report.c:429
>  __lock_acquire+0x3069/0x3690 kernel/locking/lockdep.c:3246
>  lock_acquire+0x22d/0x560 kernel/locking/lockdep.c:3855
>  __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
>  _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151
>  spin_lock include/linux/spinlock.h:299 [inline]
>  gadgetfs_suspend+0x89/0x130 drivers/usb/gadget/legacy/inode.c:1682
>  set_link_state+0x88e/0xae0 drivers/usb/gadget/udc/dummy_hcd.c:455
>  dummy_hub_control+0xd7e/0x1fb0 drivers/usb/gadget/udc/dummy_hcd.c:2074
>  rh_call_control drivers/usb/core/hcd.c:689 [inline]
>  rh_urb_enqueue drivers/usb/core/hcd.c:846 [inline]
>  usb_hcd_submit_urb+0x92f/0x20b0 drivers/usb/core/hcd.c:1650
>  usb_submit_urb+0x8b2/0x12c0 drivers/usb/core/urb.c:542
>  usb_start_wait_urb+0x148/0x5b0 drivers/usb/core/message.c:56
>  usb_internal_control_msg drivers/usb/core/message.c:100 [inline]
>  usb_control_msg+0x341/0x4d0 drivers/usb/core/message.c:151
>  usb_clear_port_feature+0x74/0xa0 drivers/usb/core/hub.c:412
>  hub_port_disable+0x123/0x510 drivers/usb/core/hub.c:4177
>  hub_port_init+0x1ed/0x2940 drivers/usb/core/hub.c:4648
>  hub_port_connect drivers/usb/core/hub.c:4826 [inline]
>  hub_port_connect_change drivers/usb/core/hub.c:4999 [inline]
>  port_event drivers/usb/core/hub.c:5105 [inline]
>  hub_event+0x1ae1/0x3d40 drivers/usb/core/hub.c:5185
>  process_one_work+0xc08/0x1bd0 kernel/workqueue.c:2097
>  process_scheduled_works kernel/workqueue.c:2157 [inline]
>  worker_thread+0xb2b/0x1860 kernel/workqueue.c:2233
>  kthread+0x363/0x440 kernel/kthread.c:231
>  ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:424
>
> Allocated by task 9958:
>  save_stack_trace+0x1b/0x20 arch/x86/kernel/stacktrace.c:59
>  save_stack+0x43/0xd0 mm/kasan/kasan.c:513
>  set_track mm/kasan/kasan.c:525 [inline]
>  kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:617
>  kmem_cache_alloc_trace+0x87/0x280 mm/slub.c:2745
>  kmalloc include/linux/slab.h:492 [inline]
>  kzalloc include/linux/slab.h:665 [inline]
>  dev_new drivers/usb/gadget/legacy/inode.c:170 [inline]
>  gadgetfs_fill_super+0x24f/0x540 drivers/usb/gadget/legacy/inode.c:1993
>  mount_single+0xf6/0x160 fs/super.c:1192
>  gadgetfs_mount+0x31/0x40 drivers/usb/gadget/legacy/inode.c:2019
>  mount_fs+0x9c/0x2d0 fs/super.c:1223
>  vfs_kern_mount.part.25+0xcb/0x490 fs/namespace.c:976
>  vfs_kern_mount fs/namespace.c:2509 [inline]
>  do_new_mount fs/namespace.c:2512 [inline]
>  do_mount+0x41b/0x2d90 fs/namespace.c:2834
>  SYSC_mount fs/namespace.c:3050 [inline]
>  SyS_mount+0xb0/0x120 fs/namespace.c:3027
>  entry_SYSCALL_64_fastpath+0x1f/0xbe
>
> Freed by task 9960:
>  save_stack_trace+0x1b/0x20 arch/x86/kernel/stacktrace.c:59
>  save_stack+0x43/0xd0 mm/kasan/kasan.c:513
>  set_track mm/kasan/kasan.c:525 [inline]
>  kasan_slab_free+0x72/0xc0 mm/kasan/kasan.c:590
>  slab_free_hook mm/slub.c:1357 [inline]
>  slab_free_freelist_hook mm/slub.c:1379 [inline]
>  slab_free mm/slub.c:2961 [inline]
>  kfree+0xed/0x2b0 mm/slub.c:3882
>  put_dev+0x124/0x160 drivers/usb/gadget/legacy/inode.c:163
>  gadgetfs_kill_sb+0x33/0x60 drivers/usb/gadget/legacy/inode.c:2027
>  deactivate_locked_super+0x8d/0xd0 fs/super.c:309
>  deactivate_super+0x21e/0x310 fs/super.c:340
>  cleanup_mnt+0xb7/0x150 fs/namespace.c:1112
>  __cleanup_mnt+0x1b/0x20 fs/namespace.c:1119
>  task_work_run+0x1a0/0x280 kernel/task_work.c:116
>  exit_task_work include/linux/task_work.h:21 [inline]
>  do_exit+0x18a8/0x2820 kernel/exit.c:878
>  do_group_exit+0x14e/0x420 kernel/exit.c:982
>  get_signal+0x784/0x1780 kernel/signal.c:2318
>  do_signal+0xd7/0x2130 arch/x86/kernel/signal.c:808
>  exit_to_usermode_loop+0x1ac/0x240 arch/x86/entry/common.c:157
>  prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline]
>  syscall_return_slowpath+0x3ba/0x410 arch/x86/entry/common.c:263
>  entry_SYSCALL_64_fastpath+0xbc/0xbe
>
> The buggy address belongs to the object at ffff88003a2bdae0
>  which belongs to the cache kmalloc-1024 of size 1024
> The buggy address is located 24 bytes inside of
>  1024-byte region [ffff88003a2bdae0, ffff88003a2bdee0)
> The buggy address belongs to the page:
> page:ffffea0000e8ae00 count:1 mapcount:0 mapping:          (null)
> index:0x0 compound_mapcount: 0
> flags: 0x100000000008100(slab|head)
> raw: 0100000000008100 0000000000000000 0000000000000000 0000000100170017
> raw: ffffea0000ed3020 ffffea0000f5f820 ffff88003e80efc0 0000000000000000
> page dumped because: kasan: bad access detected
>
> Memory state around the buggy address:
>  ffff88003a2bd980: fb fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>  ffff88003a2bda00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> >ffff88003a2bda80: fc fc fc fc fc fc fc fc fc fc fc fc fb fb fb fb
>                                                                 ^
>  ffff88003a2bdb00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>  ffff88003a2bdb80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ==================================================================

What this means is that the gadgetfs_suspend() routine was trying to
access dev->lock after it had been deallocated.  The root cause is a
race in the dummy_hcd driver; the dummy_udc_stop() routine can race
with the rest of the driver because it contains no locking.  And even
when proper locking is added, it can still race with the
set_link_state() function because that function incorrectly drops the
private spinlock before invoking any gadget driver callbacks.

The result of this race, as seen above, is that set_link_state() can
invoke a callback in gadgetfs even after gadgetfs has been unbound
from dummy_hcd's UDC and its private data structures have been
deallocated.

include/linux/usb/gadget.h documents that the ->reset, ->disconnect,
->suspend, and ->resume callbacks may be invoked in interrupt context.
In general this is necessary, to prevent races with gadget driver
removal.  This patch fixes dummy_hcd to retain the spinlock across
these calls, and it adds a spinlock acquisition to dummy_udc_stop() to
prevent the race.

The net2280 driver makes the same mistake of dropping the private
spinlock for its ->disconnect and ->reset callback invocations.  The
patch fixes it too.

Lastly, since gadgetfs_suspend() may be invoked in interrupt context,
it cannot assume that interrupts are enabled when it runs.  It must
use spin_lock_irqsave() instead of spin_lock_irq().  The patch fixes
that bug as well.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-and-tested-by: Andrey Konovalov <andreyknvl@google.com>
Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/usb/gadget/legacy/inode.c  |    5 +++--
 drivers/usb/gadget/udc/dummy_hcd.c |   13 ++++---------
 drivers/usb/gadget/udc/net2280.c   |    9 +--------
 3 files changed, 8 insertions(+), 19 deletions(-)

--- a/drivers/usb/gadget/legacy/inode.c
+++ b/drivers/usb/gadget/legacy/inode.c
@@ -1676,9 +1676,10 @@ static void
 gadgetfs_suspend (struct usb_gadget *gadget)
 {
 	struct dev_data		*dev = get_gadget_data (gadget);
+	unsigned long		flags;
 
 	INFO (dev, "suspended from state %d\n", dev->state);
-	spin_lock (&dev->lock);
+	spin_lock_irqsave(&dev->lock, flags);
 	switch (dev->state) {
 	case STATE_DEV_SETUP:		// VERY odd... host died??
 	case STATE_DEV_CONNECTED:
@@ -1689,7 +1690,7 @@ gadgetfs_suspend (struct usb_gadget *gad
 	default:
 		break;
 	}
-	spin_unlock (&dev->lock);
+	spin_unlock_irqrestore(&dev->lock, flags);
 }
 
 static struct usb_gadget_driver gadgetfs_driver = {
--- a/drivers/usb/gadget/udc/dummy_hcd.c
+++ b/drivers/usb/gadget/udc/dummy_hcd.c
@@ -442,23 +442,16 @@ static void set_link_state(struct dummy_
 		/* Report reset and disconnect events to the driver */
 		if (dum->driver && (disconnect || reset)) {
 			stop_activity(dum);
-			spin_unlock(&dum->lock);
 			if (reset)
 				usb_gadget_udc_reset(&dum->gadget, dum->driver);
 			else
 				dum->driver->disconnect(&dum->gadget);
-			spin_lock(&dum->lock);
 		}
 	} else if (dum_hcd->active != dum_hcd->old_active) {
-		if (dum_hcd->old_active && dum->driver->suspend) {
-			spin_unlock(&dum->lock);
+		if (dum_hcd->old_active && dum->driver->suspend)
 			dum->driver->suspend(&dum->gadget);
-			spin_lock(&dum->lock);
-		} else if (!dum_hcd->old_active &&  dum->driver->resume) {
-			spin_unlock(&dum->lock);
+		else if (!dum_hcd->old_active &&  dum->driver->resume)
 			dum->driver->resume(&dum->gadget);
-			spin_lock(&dum->lock);
-		}
 	}
 
 	dum_hcd->old_status = dum_hcd->port_status;
@@ -985,7 +978,9 @@ static int dummy_udc_stop(struct usb_gad
 	struct dummy_hcd	*dum_hcd = gadget_to_dummy_hcd(g);
 	struct dummy		*dum = dum_hcd->dum;
 
+	spin_lock_irq(&dum->lock);
 	dum->driver = NULL;
+	spin_unlock_irq(&dum->lock);
 
 	return 0;
 }
--- a/drivers/usb/gadget/udc/net2280.c
+++ b/drivers/usb/gadget/udc/net2280.c
@@ -2425,11 +2425,8 @@ static void stop_activity(struct net2280
 		nuke(&dev->ep[i]);
 
 	/* report disconnect; the driver is already quiesced */
-	if (driver) {
-		spin_unlock(&dev->lock);
+	if (driver)
 		driver->disconnect(&dev->gadget);
-		spin_lock(&dev->lock);
-	}
 
 	usb_reinit(dev);
 }
@@ -3275,8 +3272,6 @@ next_endpoints:
 		BIT(PCI_RETRY_ABORT_INTERRUPT))
 
 static void handle_stat1_irqs(struct net2280 *dev, u32 stat)
-__releases(dev->lock)
-__acquires(dev->lock)
 {
 	struct net2280_ep	*ep;
 	u32			tmp, num, mask, scratch;
@@ -3317,14 +3312,12 @@ __acquires(dev->lock)
 			if (disconnect || reset) {
 				stop_activity(dev, dev->driver);
 				ep0_start(dev);
-				spin_unlock(&dev->lock);
 				if (reset)
 					usb_gadget_udc_reset
 						(&dev->gadget, dev->driver);
 				else
 					(dev->driver->disconnect)
 						(&dev->gadget);
-				spin_lock(&dev->lock);
 				return;
 			}
 		}

[PATCH 4.4 23/30] mm/memory-failure.c: use compound_head() flags for huge pages

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: James Morse <james.morse@arm.com>

commit 7258ae5c5a2ce2f5969e8b18b881be40ab55433d upstream.

memory_failure() chooses a recovery action function based on the page
flags.  For huge pages it uses the tail page flags which don't have
anything interesting set, resulting in:

> Memory failure: 0x9be3b4: Unknown page state
> Memory failure: 0x9be3b4: recovery action for unknown page: Failed

Instead, save a copy of the head page's flags if this is a huge page,
this means if there are no relevant flags for this tail page, we use the
head pages flags instead.  This results in the me_huge_page() recovery
action being called:

> Memory failure: 0x9b7969: recovery action for huge page: Delayed

For hugepages that have not yet been allocated, this allows the hugepage
to be dequeued.

Fixes: 524fca1e7356 ("HWPOISON: fix misjudgement of page_action() for errors on mlocked pages")
Link: http://lkml.kernel.org/r/20170524130204.21845-1-james.morse@arm.com
Signed-off-by: James Morse <james.morse@arm.com>
Tested-by: Punit Agrawal <punit.agrawal@arm.com>
Acked-by: Punit Agrawal <punit.agrawal@arm.com>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 mm/memory-failure.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1208,7 +1208,10 @@ int memory_failure(unsigned long pfn, in
 	 * page_remove_rmap() in try_to_unmap_one(). So to determine page status
 	 * correctly, we save a copy of the page flags at this time.
 	 */
-	page_flags = p->flags;
+	if (PageHuge(p))
+		page_flags = hpage->flags;
+	else
+		page_flags = p->flags;
 
 	/*
 	 * unpoison always clear PG_hwpoison inside page lock

[PATCH 4.4 24/30] swap: cond_resched in swap_cgroup_prepare()

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Yu Zhao <yuzhao@google.com>

commit ef70762948dde012146926720b70e79736336764 upstream.

I saw need_resched() warnings when swapping on large swapfile (TBs)
because continuously allocating many pages in swap_cgroup_prepare() took
too long.

We already cond_resched when freeing page in swap_cgroup_swapoff().  Do
the same for the page allocation.

Link: http://lkml.kernel.org/r/20170604200109.17606-1-yuzhao@google.com
Signed-off-by: Yu Zhao <yuzhao@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 mm/swap_cgroup.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/mm/swap_cgroup.c
+++ b/mm/swap_cgroup.c
@@ -48,6 +48,9 @@ static int swap_cgroup_prepare(int type)
 		if (!page)
 			goto not_enough_page;
 		ctrl->map[idx] = page;
+
+		if (!(idx % SWAP_CLUSTER_MAX))
+			cond_resched();
 	}
 	return 0;
 not_enough_page:

[PATCH 4.4 25/30] genirq: Release resources in __setup_irq() error path

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Heiner Kallweit <hkallweit1@gmail.com>

commit fa07ab72cbb0d843429e61bf179308aed6cbe0dd upstream.

In case __irq_set_trigger() fails the resources requested via
irq_request_resources() are not released.

Add the missing release call into the error handling path.

Fixes: c1bacbae8192 ("genirq: Provide irq_request/release_resources chip callbacks")
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/655538f5-cb20-a892-ff15-fbd2dd1fa4ec@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 kernel/irq/manage.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -1287,8 +1287,10 @@ __setup_irq(unsigned int irq, struct irq
 			ret = __irq_set_trigger(desc,
 						new->flags & IRQF_TRIGGER_MASK);
 
-			if (ret)
+			if (ret) {
+				irq_release_resources(desc);
 				goto out_mask;
+			}
 		}
 
 		desc->istate &= ~(IRQS_AUTODETECT | IRQS_SPURIOUS_DISABLED | \

[PATCH 4.4 26/30] alarmtimer: Prevent overflow of relative timers

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Thomas Gleixner <tglx@linutronix.de>

commit f4781e76f90df7aec400635d73ea4c35ee1d4765 upstream.

Andrey reported a alartimer related RCU stall while fuzzing the kernel with
syzkaller.

The reason for this is an overflow in ktime_add() which brings the
resulting time into negative space and causes immediate expiry of the
timer. The following rearm with a small interval does not bring the timer
back into positive space due to the same issue.

This results in a permanent firing alarmtimer which hogs the CPU.

Use ktime_add_safe() instead which detects the overflow and clamps the
result to KTIME_SEC_MAX.

Reported-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Kostya Serebryany <kcc@google.com>
Cc: syzkaller <syzkaller@googlegroups.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Link: http://lkml.kernel.org/r/20170530211655.802921648@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 kernel/time/alarmtimer.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -339,7 +339,7 @@ void alarm_start_relative(struct alarm *
 {
 	struct alarm_base *base = &alarm_bases[alarm->type];
 
-	start = ktime_add(start, base->gettime());
+	start = ktime_add_safe(start, base->gettime());
 	alarm_start(alarm, start);
 }
 EXPORT_SYMBOL_GPL(alarm_start_relative);
@@ -425,7 +425,7 @@ u64 alarm_forward(struct alarm *alarm, k
 		overrun++;
 	}
 
-	alarm->node.expires = ktime_add(alarm->node.expires, interval);
+	alarm->node.expires = ktime_add_safe(alarm->node.expires, interval);
 	return overrun;
 }
 EXPORT_SYMBOL_GPL(alarm_forward);
@@ -617,7 +617,7 @@ static int alarm_timer_set(struct k_itim
 		ktime_t now;
 
 		now = alarm_bases[timr->it.alarm.alarmtimer.type].gettime();
-		exp = ktime_add(now, exp);
+		exp = ktime_add_safe(now, exp);
 	}
 
 	alarm_start(&timr->it.alarm.alarmtimer, exp);

[PATCH 4.4 27/30] usb: dwc3: exynos fix axius clock error path to do cleanup

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Shuah Khan <shuahkh@osg.samsung.com>

commit 8ae584d1951f241efd45499f8774fd7066f22823 upstream.

Axius clock error path returns without disabling clock and suspend clock.
Fix it to disable them before returning error.

Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/usb/dwc3/dwc3-exynos.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/usb/dwc3/dwc3-exynos.c
+++ b/drivers/usb/dwc3/dwc3-exynos.c
@@ -148,7 +148,8 @@ static int dwc3_exynos_probe(struct plat
 		exynos->axius_clk = devm_clk_get(dev, "usbdrd30_axius_clk");
 		if (IS_ERR(exynos->axius_clk)) {
 			dev_err(dev, "no AXI UpScaler clk specified\n");
-			return -ENODEV;
+			ret = -ENODEV;
+			goto axius_clk_err;
 		}
 		clk_prepare_enable(exynos->axius_clk);
 	} else {
@@ -206,6 +207,7 @@ err3:
 	regulator_disable(exynos->vdd33);
 err2:
 	clk_disable_unprepare(exynos->axius_clk);
+axius_clk_err:
 	clk_disable_unprepare(exynos->susp_clk);
 	clk_disable_unprepare(exynos->clk);
 	return ret;

[PATCH 4.4 28/30] MIPS: Fix bnezc/jialc return address calculation

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Paul Burton <paul.burton@imgtec.com>

commit 1a73d9310e093fc3adffba4d0a67b9fab2ee3f63 upstream.

The code handling the pop76 opcode (ie. bnezc & jialc instructions) in
__compute_return_epc_for_insn() needs to set the value of $31 in the
jialc case, which is encoded with rs = 0. However its check to
differentiate bnezc (rs != 0) from jialc (rs = 0) was unfortunately
backwards, meaning that if we emulate a bnezc instruction we clobber $31
& if we emulate a jialc instruction it actually behaves like a jic
instruction.

Fix this by inverting the check of rs to match the way the instructions
are actually encoded.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Fixes: 28d6f93d201d ("MIPS: Emulate the new MIPS R6 BNEZC and JIALC instructions")
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16178/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/mips/kernel/branch.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/arch/mips/kernel/branch.c
+++ b/arch/mips/kernel/branch.c
@@ -816,8 +816,10 @@ int __compute_return_epc_for_insn(struct
 			break;
 		}
 		/* Compact branch: BNEZC || JIALC */
-		if (insn.i_format.rs)
+		if (!insn.i_format.rs) {
+			/* JIALC: set $31/ra */
 			regs->regs[31] = epc + 4;
+		}
 		regs->cp0_epc += 8;
 		break;
 #endif

[PATCH 4.4 29/30] alarmtimer: Rate limit periodic intervals

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Thomas Gleixner <tglx@linutronix.de>

commit ff86bf0c65f14346bf2440534f9ba5ac232c39a0 upstream.

The alarmtimer code has another source of potentially rearming itself too
fast. Interval timers with a very samll interval have a similar CPU hog
effect as the previously fixed overflow issue.

The reason is that alarmtimers do not implement the normal protection
against this kind of problem which the other posix timer use:

  timer expires -> queue signal -> deliver signal -> rearm timer

This scheme brings the rearming under scheduler control and prevents
permanently firing timers which hog the CPU.

Bringing this scheme to the alarm timer code is a major overhaul because it
lacks all the necessary mechanisms completely.

So for a quick fix limit the interval to one jiffie. This is not
problematic in practice as alarmtimers are usually backed by an RTC for
suspend which have 1 second resolution. It could be therefor argued that
the resolution of this clock should be set to 1 second in general, but
that's outside the scope of this fix.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Kostya Serebryany <kcc@google.com>
Cc: syzkaller <syzkaller@googlegroups.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Link: http://lkml.kernel.org/r/20170530211655.896767100@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>


---
 kernel/time/alarmtimer.c |    8 ++++++++
 1 file changed, 8 insertions(+)

--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -611,6 +611,14 @@ static int alarm_timer_set(struct k_itim
 
 	/* start the timer */
 	timr->it.alarm.interval = timespec_to_ktime(new_setting->it_interval);
+
+	/*
+	 * Rate limit to the tick as a hot fix to prevent DOS. Will be
+	 * mopped up later.
+	 */
+	if (ktime_to_ns(timr->it.alarm.interval) < TICK_NSEC)
+		timr->it.alarm.interval = ktime_set(0, TICK_NSEC);
+
 	exp = timespec_to_ktime(new_setting->it_value);
 	/* Convert (if necessary) to absolute time */
 	if (flags != TIMER_ABSTIME) {

[PATCH 4.4 30/30] mm: larger stack guard gap, between vmas

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Hugh Dickins <hughd@google.com>

commit 1be7107fbe18eed3e319a6c3e83c78254b693acb upstream.

Stack guard page is a useful feature to reduce a risk of stack smashing
into a different mapping. We have been using a single page gap which
is sufficient to prevent having stack adjacent to a different mapping.
But this seems to be insufficient in the light of the stack usage in
userspace. E.g. glibc uses as large as 64kB alloca() in many commonly
used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX]
which is 256kB or stack strings with MAX_ARG_STRLEN.

This will become especially dangerous for suid binaries and the default
no limit for the stack size limit because those applications can be
tricked to consume a large portion of the stack and a single glibc call
could jump over the guard page. These attacks are not theoretical,
unfortunatelly.

Make those attacks less probable by increasing the stack guard gap
to 1MB (on systems with 4k pages; but make it depend on the page size
because systems with larger base pages might cap stack allocations in
the PAGE_SIZE units) which should cover larger alloca() and VLA stack
allocations. It is obviously not a full fix because the problem is
somehow inherent, but it should reduce attack space a lot.

One could argue that the gap size should be configurable from userspace,
but that can be done later when somebody finds that the new 1MB is wrong
for some special case applications.  For now, add a kernel command line
option (stack_guard_gap) to specify the stack gap size (in page units).

Implementation wise, first delete all the old code for stack guard page:
because although we could get away with accounting one extra page in a
stack vma, accounting a larger gap can break userspace - case in point,
a program run with "ulimit -S -v 20000" failed when the 1MB gap was
counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK
and strict non-overcommit mode.

Instead of keeping gap inside the stack vma, maintain the stack guard
gap as a gap between vmas: using vm_start_gap() in place of vm_start
(or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few
places which need to respect the gap - mainly arch_get_unmapped_area(),
and and the vma tree's subtree_gap support for that.

Original-patch-by: Oleg Nesterov <oleg@redhat.com>
Original-patch-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Tested-by: Helge Deller <deller@gmx.de> # parisc
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[wt: backport to 4.11: adjust context]
[wt: backport to 4.9: adjust context ; kernel doc was not in admin-guide]
[wt: backport to 4.4: adjust context ; drop ppc hugetlb_radix changes]
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 Documentation/kernel-parameters.txt |    7 +
 arch/arc/mm/mmap.c                  |    2 
 arch/arm/mm/mmap.c                  |    4 
 arch/frv/mm/elf-fdpic.c             |    2 
 arch/mips/mm/mmap.c                 |    2 
 arch/parisc/kernel/sys_parisc.c     |   15 ++-
 arch/powerpc/mm/slice.c             |    2 
 arch/s390/mm/mmap.c                 |    4 
 arch/sh/mm/mmap.c                   |    4 
 arch/sparc/kernel/sys_sparc_64.c    |    4 
 arch/sparc/mm/hugetlbpage.c         |    2 
 arch/tile/mm/hugetlbpage.c          |    2 
 arch/x86/kernel/sys_x86_64.c        |    4 
 arch/x86/mm/hugetlbpage.c           |    2 
 arch/xtensa/kernel/syscall.c        |    2 
 fs/hugetlbfs/inode.c                |    2 
 fs/proc/task_mmu.c                  |    4 
 include/linux/mm.h                  |   55 ++++++-------
 mm/gup.c                            |    5 -
 mm/memory.c                         |   38 ---------
 mm/mmap.c                           |  147 +++++++++++++++++++++---------------
 21 files changed, 148 insertions(+), 161 deletions(-)

--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -3580,6 +3580,13 @@ bytes respectively. Such letter suffixes
 	spia_pedr=
 	spia_peddr=
 
+	stack_guard_gap=	[MM]
+			override the default stack gap protection. The value
+			is in page units and it defines how many pages prior
+			to (for stacks growing down) resp. after (for stacks
+			growing up) the main stack are reserved for no other
+			mapping. Default value is 256 pages.
+
 	stacktrace	[FTRACE]
 			Enabled the stack tracer on boot up.
 
--- a/arch/arc/mm/mmap.c
+++ b/arch/arc/mm/mmap.c
@@ -64,7 +64,7 @@ arch_get_unmapped_area(struct file *filp
 
 		vma = find_vma(mm, addr);
 		if (TASK_SIZE - len >= addr &&
-		    (!vma || addr + len <= vma->vm_start))
+		    (!vma || addr + len <= vm_start_gap(vma)))
 			return addr;
 	}
 
--- a/arch/arm/mm/mmap.c
+++ b/arch/arm/mm/mmap.c
@@ -89,7 +89,7 @@ arch_get_unmapped_area(struct file *filp
 
 		vma = find_vma(mm, addr);
 		if (TASK_SIZE - len >= addr &&
-		    (!vma || addr + len <= vma->vm_start))
+		    (!vma || addr + len <= vm_start_gap(vma)))
 			return addr;
 	}
 
@@ -140,7 +140,7 @@ arch_get_unmapped_area_topdown(struct fi
 			addr = PAGE_ALIGN(addr);
 		vma = find_vma(mm, addr);
 		if (TASK_SIZE - len >= addr &&
-				(!vma || addr + len <= vma->vm_start))
+				(!vma || addr + len <= vm_start_gap(vma)))
 			return addr;
 	}
 
--- a/arch/frv/mm/elf-fdpic.c
+++ b/arch/frv/mm/elf-fdpic.c
@@ -74,7 +74,7 @@ unsigned long arch_get_unmapped_area(str
 		addr = PAGE_ALIGN(addr);
 		vma = find_vma(current->mm, addr);
 		if (TASK_SIZE - len >= addr &&
-		    (!vma || addr + len <= vma->vm_start))
+		    (!vma || addr + len <= vm_start_gap(vma)))
 			goto success;
 	}
 
--- a/arch/mips/mm/mmap.c
+++ b/arch/mips/mm/mmap.c
@@ -92,7 +92,7 @@ static unsigned long arch_get_unmapped_a
 
 		vma = find_vma(mm, addr);
 		if (TASK_SIZE - len >= addr &&
-		    (!vma || addr + len <= vma->vm_start))
+		    (!vma || addr + len <= vm_start_gap(vma)))
 			return addr;
 	}
 
--- a/arch/parisc/kernel/sys_parisc.c
+++ b/arch/parisc/kernel/sys_parisc.c
@@ -88,7 +88,7 @@ unsigned long arch_get_unmapped_area(str
 		unsigned long len, unsigned long pgoff, unsigned long flags)
 {
 	struct mm_struct *mm = current->mm;
-	struct vm_area_struct *vma;
+	struct vm_area_struct *vma, *prev;
 	unsigned long task_size = TASK_SIZE;
 	int do_color_align, last_mmap;
 	struct vm_unmapped_area_info info;
@@ -115,9 +115,10 @@ unsigned long arch_get_unmapped_area(str
 		else
 			addr = PAGE_ALIGN(addr);
 
-		vma = find_vma(mm, addr);
+		vma = find_vma_prev(mm, addr, &prev);
 		if (task_size - len >= addr &&
-		    (!vma || addr + len <= vma->vm_start))
+		    (!vma || addr + len <= vm_start_gap(vma)) &&
+		    (!prev || addr >= vm_end_gap(prev)))
 			goto found_addr;
 	}
 
@@ -141,7 +142,7 @@ arch_get_unmapped_area_topdown(struct fi
 			  const unsigned long len, const unsigned long pgoff,
 			  const unsigned long flags)
 {
-	struct vm_area_struct *vma;
+	struct vm_area_struct *vma, *prev;
 	struct mm_struct *mm = current->mm;
 	unsigned long addr = addr0;
 	int do_color_align, last_mmap;
@@ -175,9 +176,11 @@ arch_get_unmapped_area_topdown(struct fi
 			addr = COLOR_ALIGN(addr, last_mmap, pgoff);
 		else
 			addr = PAGE_ALIGN(addr);
-		vma = find_vma(mm, addr);
+
+		vma = find_vma_prev(mm, addr, &prev);
 		if (TASK_SIZE - len >= addr &&
-		    (!vma || addr + len <= vma->vm_start))
+		    (!vma || addr + len <= vm_start_gap(vma)) &&
+		    (!prev || addr >= vm_end_gap(prev)))
 			goto found_addr;
 	}
 
--- a/arch/powerpc/mm/slice.c
+++ b/arch/powerpc/mm/slice.c
@@ -105,7 +105,7 @@ static int slice_area_is_free(struct mm_
 	if ((mm->task_size - len) < addr)
 		return 0;
 	vma = find_vma(mm, addr);
-	return (!vma || (addr + len) <= vma->vm_start);
+	return (!vma || (addr + len) <= vm_start_gap(vma));
 }
 
 static int slice_low_has_vma(struct mm_struct *mm, unsigned long slice)
--- a/arch/s390/mm/mmap.c
+++ b/arch/s390/mm/mmap.c
@@ -97,7 +97,7 @@ arch_get_unmapped_area(struct file *filp
 		addr = PAGE_ALIGN(addr);
 		vma = find_vma(mm, addr);
 		if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
-		    (!vma || addr + len <= vma->vm_start))
+		    (!vma || addr + len <= vm_start_gap(vma)))
 			return addr;
 	}
 
@@ -135,7 +135,7 @@ arch_get_unmapped_area_topdown(struct fi
 		addr = PAGE_ALIGN(addr);
 		vma = find_vma(mm, addr);
 		if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
-				(!vma || addr + len <= vma->vm_start))
+				(!vma || addr + len <= vm_start_gap(vma)))
 			return addr;
 	}
 
--- a/arch/sh/mm/mmap.c
+++ b/arch/sh/mm/mmap.c
@@ -63,7 +63,7 @@ unsigned long arch_get_unmapped_area(str
 
 		vma = find_vma(mm, addr);
 		if (TASK_SIZE - len >= addr &&
-		    (!vma || addr + len <= vma->vm_start))
+		    (!vma || addr + len <= vm_start_gap(vma)))
 			return addr;
 	}
 
@@ -113,7 +113,7 @@ arch_get_unmapped_area_topdown(struct fi
 
 		vma = find_vma(mm, addr);
 		if (TASK_SIZE - len >= addr &&
-		    (!vma || addr + len <= vma->vm_start))
+		    (!vma || addr + len <= vm_start_gap(vma)))
 			return addr;
 	}
 
--- a/arch/sparc/kernel/sys_sparc_64.c
+++ b/arch/sparc/kernel/sys_sparc_64.c
@@ -118,7 +118,7 @@ unsigned long arch_get_unmapped_area(str
 
 		vma = find_vma(mm, addr);
 		if (task_size - len >= addr &&
-		    (!vma || addr + len <= vma->vm_start))
+		    (!vma || addr + len <= vm_start_gap(vma)))
 			return addr;
 	}
 
@@ -181,7 +181,7 @@ arch_get_unmapped_area_topdown(struct fi
 
 		vma = find_vma(mm, addr);
 		if (task_size - len >= addr &&
-		    (!vma || addr + len <= vma->vm_start))
+		    (!vma || addr + len <= vm_start_gap(vma)))
 			return addr;
 	}
 
--- a/arch/sparc/mm/hugetlbpage.c
+++ b/arch/sparc/mm/hugetlbpage.c
@@ -115,7 +115,7 @@ hugetlb_get_unmapped_area(struct file *f
 		addr = ALIGN(addr, HPAGE_SIZE);
 		vma = find_vma(mm, addr);
 		if (task_size - len >= addr &&
-		    (!vma || addr + len <= vma->vm_start))
+		    (!vma || addr + len <= vm_start_gap(vma)))
 			return addr;
 	}
 	if (mm->get_unmapped_area == arch_get_unmapped_area)
--- a/arch/tile/mm/hugetlbpage.c
+++ b/arch/tile/mm/hugetlbpage.c
@@ -232,7 +232,7 @@ unsigned long hugetlb_get_unmapped_area(
 		addr = ALIGN(addr, huge_page_size(h));
 		vma = find_vma(mm, addr);
 		if (TASK_SIZE - len >= addr &&
-		    (!vma || addr + len <= vma->vm_start))
+		    (!vma || addr + len <= vm_start_gap(vma)))
 			return addr;
 	}
 	if (current->mm->get_unmapped_area == arch_get_unmapped_area)
--- a/arch/x86/kernel/sys_x86_64.c
+++ b/arch/x86/kernel/sys_x86_64.c
@@ -143,7 +143,7 @@ arch_get_unmapped_area(struct file *filp
 		addr = PAGE_ALIGN(addr);
 		vma = find_vma(mm, addr);
 		if (end - len >= addr &&
-		    (!vma || addr + len <= vma->vm_start))
+		    (!vma || addr + len <= vm_start_gap(vma)))
 			return addr;
 	}
 
@@ -186,7 +186,7 @@ arch_get_unmapped_area_topdown(struct fi
 		addr = PAGE_ALIGN(addr);
 		vma = find_vma(mm, addr);
 		if (TASK_SIZE - len >= addr &&
-				(!vma || addr + len <= vma->vm_start))
+				(!vma || addr + len <= vm_start_gap(vma)))
 			return addr;
 	}
 
--- a/arch/x86/mm/hugetlbpage.c
+++ b/arch/x86/mm/hugetlbpage.c
@@ -144,7 +144,7 @@ hugetlb_get_unmapped_area(struct file *f
 		addr = ALIGN(addr, huge_page_size(h));
 		vma = find_vma(mm, addr);
 		if (TASK_SIZE - len >= addr &&
-		    (!vma || addr + len <= vma->vm_start))
+		    (!vma || addr + len <= vm_start_gap(vma)))
 			return addr;
 	}
 	if (mm->get_unmapped_area == arch_get_unmapped_area)
--- a/arch/xtensa/kernel/syscall.c
+++ b/arch/xtensa/kernel/syscall.c
@@ -87,7 +87,7 @@ unsigned long arch_get_unmapped_area(str
 		/* At this point:  (!vmm || addr < vmm->vm_end). */
 		if (TASK_SIZE - len < addr)
 			return -ENOMEM;
-		if (!vmm || addr + len <= vmm->vm_start)
+		if (!vmm || addr + len <= vm_start_gap(vmm))
 			return addr;
 		addr = vmm->vm_end;
 		if (flags & MAP_SHARED)
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -191,7 +191,7 @@ hugetlb_get_unmapped_area(struct file *f
 		addr = ALIGN(addr, huge_page_size(h));
 		vma = find_vma(mm, addr);
 		if (TASK_SIZE - len >= addr &&
-		    (!vma || addr + len <= vma->vm_start))
+		    (!vma || addr + len <= vm_start_gap(vma)))
 			return addr;
 	}
 
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -295,11 +295,7 @@ show_map_vma(struct seq_file *m, struct
 
 	/* We don't show the stack guard page in /proc/maps */
 	start = vma->vm_start;
-	if (stack_guard_page_start(vma, start))
-		start += PAGE_SIZE;
 	end = vma->vm_end;
-	if (stack_guard_page_end(vma, end))
-		end -= PAGE_SIZE;
 
 	seq_setwidth(m, 25 + sizeof(void *) * 6 - 1);
 	seq_printf(m, "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu ",
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1278,41 +1278,11 @@ int clear_page_dirty_for_io(struct page
 
 int get_cmdline(struct task_struct *task, char *buffer, int buflen);
 
-/* Is the vma a continuation of the stack vma above it? */
-static inline int vma_growsdown(struct vm_area_struct *vma, unsigned long addr)
-{
-	return vma && (vma->vm_end == addr) && (vma->vm_flags & VM_GROWSDOWN);
-}
-
 static inline bool vma_is_anonymous(struct vm_area_struct *vma)
 {
 	return !vma->vm_ops;
 }
 
-static inline int stack_guard_page_start(struct vm_area_struct *vma,
-					     unsigned long addr)
-{
-	return (vma->vm_flags & VM_GROWSDOWN) &&
-		(vma->vm_start == addr) &&
-		!vma_growsdown(vma->vm_prev, addr);
-}
-
-/* Is the vma a continuation of the stack vma below it? */
-static inline int vma_growsup(struct vm_area_struct *vma, unsigned long addr)
-{
-	return vma && (vma->vm_start == addr) && (vma->vm_flags & VM_GROWSUP);
-}
-
-static inline int stack_guard_page_end(struct vm_area_struct *vma,
-					   unsigned long addr)
-{
-	return (vma->vm_flags & VM_GROWSUP) &&
-		(vma->vm_end == addr) &&
-		!vma_growsup(vma->vm_next, addr);
-}
-
-int vma_is_stack_for_task(struct vm_area_struct *vma, struct task_struct *t);
-
 extern unsigned long move_page_tables(struct vm_area_struct *vma,
 		unsigned long old_addr, struct vm_area_struct *new_vma,
 		unsigned long new_addr, unsigned long len,
@@ -2012,6 +1982,7 @@ void page_cache_async_readahead(struct a
 				pgoff_t offset,
 				unsigned long size);
 
+extern unsigned long stack_guard_gap;
 /* Generic expand stack which grows the stack according to GROWS{UP,DOWN} */
 extern int expand_stack(struct vm_area_struct *vma, unsigned long address);
 
@@ -2040,6 +2011,30 @@ static inline struct vm_area_struct * fi
 	return vma;
 }
 
+static inline unsigned long vm_start_gap(struct vm_area_struct *vma)
+{
+	unsigned long vm_start = vma->vm_start;
+
+	if (vma->vm_flags & VM_GROWSDOWN) {
+		vm_start -= stack_guard_gap;
+		if (vm_start > vma->vm_start)
+			vm_start = 0;
+	}
+	return vm_start;
+}
+
+static inline unsigned long vm_end_gap(struct vm_area_struct *vma)
+{
+	unsigned long vm_end = vma->vm_end;
+
+	if (vma->vm_flags & VM_GROWSUP) {
+		vm_end += stack_guard_gap;
+		if (vm_end < vma->vm_end)
+			vm_end = -PAGE_SIZE;
+	}
+	return vm_end;
+}
+
 static inline unsigned long vma_pages(struct vm_area_struct *vma)
 {
 	return (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -312,11 +312,6 @@ static int faultin_page(struct task_stru
 	/* mlock all present pages, but do not fault in new pages */
 	if ((*flags & (FOLL_POPULATE | FOLL_MLOCK)) == FOLL_MLOCK)
 		return -ENOENT;
-	/* For mm_populate(), just skip the stack guard page. */
-	if ((*flags & FOLL_POPULATE) &&
-			(stack_guard_page_start(vma, address) ||
-			 stack_guard_page_end(vma, address + PAGE_SIZE)))
-		return -ENOENT;
 	if (*flags & FOLL_WRITE)
 		fault_flags |= FAULT_FLAG_WRITE;
 	if (nonblocking)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2662,40 +2662,6 @@ out_release:
 }
 
 /*
- * This is like a special single-page "expand_{down|up}wards()",
- * except we must first make sure that 'address{-|+}PAGE_SIZE'
- * doesn't hit another vma.
- */
-static inline int check_stack_guard_page(struct vm_area_struct *vma, unsigned long address)
-{
-	address &= PAGE_MASK;
-	if ((vma->vm_flags & VM_GROWSDOWN) && address == vma->vm_start) {
-		struct vm_area_struct *prev = vma->vm_prev;
-
-		/*
-		 * Is there a mapping abutting this one below?
-		 *
-		 * That's only ok if it's the same stack mapping
-		 * that has gotten split..
-		 */
-		if (prev && prev->vm_end == address)
-			return prev->vm_flags & VM_GROWSDOWN ? 0 : -ENOMEM;
-
-		return expand_downwards(vma, address - PAGE_SIZE);
-	}
-	if ((vma->vm_flags & VM_GROWSUP) && address + PAGE_SIZE == vma->vm_end) {
-		struct vm_area_struct *next = vma->vm_next;
-
-		/* As VM_GROWSDOWN but s/below/above/ */
-		if (next && next->vm_start == address + PAGE_SIZE)
-			return next->vm_flags & VM_GROWSUP ? 0 : -ENOMEM;
-
-		return expand_upwards(vma, address + PAGE_SIZE);
-	}
-	return 0;
-}
-
-/*
  * We enter with non-exclusive mmap_sem (to exclude vma changes,
  * but allow concurrent faults), and pte mapped but not yet locked.
  * We return with mmap_sem still held, but pte unmapped and unlocked.
@@ -2715,10 +2681,6 @@ static int do_anonymous_page(struct mm_s
 	if (vma->vm_flags & VM_SHARED)
 		return VM_FAULT_SIGBUS;
 
-	/* Check if we need to add a guard page to the stack */
-	if (check_stack_guard_page(vma, address) < 0)
-		return VM_FAULT_SIGSEGV;
-
 	/* Use the zero-page for reads */
 	if (!(flags & FAULT_FLAG_WRITE) && !mm_forbids_zeropage(mm)) {
 		entry = pte_mkspecial(pfn_pte(my_zero_pfn(address),
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -288,6 +288,7 @@ SYSCALL_DEFINE1(brk, unsigned long, brk)
 	unsigned long retval;
 	unsigned long newbrk, oldbrk;
 	struct mm_struct *mm = current->mm;
+	struct vm_area_struct *next;
 	unsigned long min_brk;
 	bool populate;
 
@@ -332,7 +333,8 @@ SYSCALL_DEFINE1(brk, unsigned long, brk)
 	}
 
 	/* Check against existing mmap mappings. */
-	if (find_vma_intersection(mm, oldbrk, newbrk+PAGE_SIZE))
+	next = find_vma(mm, oldbrk);
+	if (next && newbrk + PAGE_SIZE > vm_start_gap(next))
 		goto out;
 
 	/* Ok, looks good - let it rip. */
@@ -355,10 +357,22 @@ out:
 
 static long vma_compute_subtree_gap(struct vm_area_struct *vma)
 {
-	unsigned long max, subtree_gap;
-	max = vma->vm_start;
-	if (vma->vm_prev)
-		max -= vma->vm_prev->vm_end;
+	unsigned long max, prev_end, subtree_gap;
+
+	/*
+	 * Note: in the rare case of a VM_GROWSDOWN above a VM_GROWSUP, we
+	 * allow two stack_guard_gaps between them here, and when choosing
+	 * an unmapped area; whereas when expanding we only require one.
+	 * That's a little inconsistent, but keeps the code here simpler.
+	 */
+	max = vm_start_gap(vma);
+	if (vma->vm_prev) {
+		prev_end = vm_end_gap(vma->vm_prev);
+		if (max > prev_end)
+			max -= prev_end;
+		else
+			max = 0;
+	}
 	if (vma->vm_rb.rb_left) {
 		subtree_gap = rb_entry(vma->vm_rb.rb_left,
 				struct vm_area_struct, vm_rb)->rb_subtree_gap;
@@ -451,7 +465,7 @@ static void validate_mm(struct mm_struct
 			anon_vma_unlock_read(anon_vma);
 		}
 
-		highest_address = vma->vm_end;
+		highest_address = vm_end_gap(vma);
 		vma = vma->vm_next;
 		i++;
 	}
@@ -620,7 +634,7 @@ void __vma_link_rb(struct mm_struct *mm,
 	if (vma->vm_next)
 		vma_gap_update(vma->vm_next);
 	else
-		mm->highest_vm_end = vma->vm_end;
+		mm->highest_vm_end = vm_end_gap(vma);
 
 	/*
 	 * vma->vm_prev wasn't known when we followed the rbtree to find the
@@ -866,7 +880,7 @@ again:			remove_next = 1 + (end > next->
 			vma_gap_update(vma);
 		if (end_changed) {
 			if (!next)
-				mm->highest_vm_end = end;
+				mm->highest_vm_end = vm_end_gap(vma);
 			else if (!adjust_next)
 				vma_gap_update(next);
 		}
@@ -1741,7 +1755,7 @@ unsigned long unmapped_area(struct vm_un
 
 	while (true) {
 		/* Visit left subtree if it looks promising */
-		gap_end = vma->vm_start;
+		gap_end = vm_start_gap(vma);
 		if (gap_end >= low_limit && vma->vm_rb.rb_left) {
 			struct vm_area_struct *left =
 				rb_entry(vma->vm_rb.rb_left,
@@ -1752,7 +1766,7 @@ unsigned long unmapped_area(struct vm_un
 			}
 		}
 
-		gap_start = vma->vm_prev ? vma->vm_prev->vm_end : 0;
+		gap_start = vma->vm_prev ? vm_end_gap(vma->vm_prev) : 0;
 check_current:
 		/* Check if current node has a suitable gap */
 		if (gap_start > high_limit)
@@ -1779,8 +1793,8 @@ check_current:
 			vma = rb_entry(rb_parent(prev),
 				       struct vm_area_struct, vm_rb);
 			if (prev == vma->vm_rb.rb_left) {
-				gap_start = vma->vm_prev->vm_end;
-				gap_end = vma->vm_start;
+				gap_start = vm_end_gap(vma->vm_prev);
+				gap_end = vm_start_gap(vma);
 				goto check_current;
 			}
 		}
@@ -1844,7 +1858,7 @@ unsigned long unmapped_area_topdown(stru
 
 	while (true) {
 		/* Visit right subtree if it looks promising */
-		gap_start = vma->vm_prev ? vma->vm_prev->vm_end : 0;
+		gap_start = vma->vm_prev ? vm_end_gap(vma->vm_prev) : 0;
 		if (gap_start <= high_limit && vma->vm_rb.rb_right) {
 			struct vm_area_struct *right =
 				rb_entry(vma->vm_rb.rb_right,
@@ -1857,7 +1871,7 @@ unsigned long unmapped_area_topdown(stru
 
 check_current:
 		/* Check if current node has a suitable gap */
-		gap_end = vma->vm_start;
+		gap_end = vm_start_gap(vma);
 		if (gap_end < low_limit)
 			return -ENOMEM;
 		if (gap_start <= high_limit && gap_end - gap_start >= length)
@@ -1883,7 +1897,7 @@ check_current:
 				       struct vm_area_struct, vm_rb);
 			if (prev == vma->vm_rb.rb_right) {
 				gap_start = vma->vm_prev ?
-					vma->vm_prev->vm_end : 0;
+					vm_end_gap(vma->vm_prev) : 0;
 				goto check_current;
 			}
 		}
@@ -1921,7 +1935,7 @@ arch_get_unmapped_area(struct file *filp
 		unsigned long len, unsigned long pgoff, unsigned long flags)
 {
 	struct mm_struct *mm = current->mm;
-	struct vm_area_struct *vma;
+	struct vm_area_struct *vma, *prev;
 	struct vm_unmapped_area_info info;
 
 	if (len > TASK_SIZE - mmap_min_addr)
@@ -1932,9 +1946,10 @@ arch_get_unmapped_area(struct file *filp
 
 	if (addr) {
 		addr = PAGE_ALIGN(addr);
-		vma = find_vma(mm, addr);
+		vma = find_vma_prev(mm, addr, &prev);
 		if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
-		    (!vma || addr + len <= vma->vm_start))
+		    (!vma || addr + len <= vm_start_gap(vma)) &&
+		    (!prev || addr >= vm_end_gap(prev)))
 			return addr;
 	}
 
@@ -1957,7 +1972,7 @@ arch_get_unmapped_area_topdown(struct fi
 			  const unsigned long len, const unsigned long pgoff,
 			  const unsigned long flags)
 {
-	struct vm_area_struct *vma;
+	struct vm_area_struct *vma, *prev;
 	struct mm_struct *mm = current->mm;
 	unsigned long addr = addr0;
 	struct vm_unmapped_area_info info;
@@ -1972,9 +1987,10 @@ arch_get_unmapped_area_topdown(struct fi
 	/* requesting a specific address */
 	if (addr) {
 		addr = PAGE_ALIGN(addr);
-		vma = find_vma(mm, addr);
+		vma = find_vma_prev(mm, addr, &prev);
 		if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
-				(!vma || addr + len <= vma->vm_start))
+				(!vma || addr + len <= vm_start_gap(vma)) &&
+				(!prev || addr >= vm_end_gap(prev)))
 			return addr;
 	}
 
@@ -2099,21 +2115,19 @@ find_vma_prev(struct mm_struct *mm, unsi
  * update accounting. This is shared with both the
  * grow-up and grow-down cases.
  */
-static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, unsigned long grow)
+static int acct_stack_growth(struct vm_area_struct *vma,
+			     unsigned long size, unsigned long grow)
 {
 	struct mm_struct *mm = vma->vm_mm;
 	struct rlimit *rlim = current->signal->rlim;
-	unsigned long new_start, actual_size;
+	unsigned long new_start;
 
 	/* address space limit tests */
 	if (!may_expand_vm(mm, grow))
 		return -ENOMEM;
 
 	/* Stack limit test */
-	actual_size = size;
-	if (size && (vma->vm_flags & (VM_GROWSUP | VM_GROWSDOWN)))
-		actual_size -= PAGE_SIZE;
-	if (actual_size > READ_ONCE(rlim[RLIMIT_STACK].rlim_cur))
+	if (size > READ_ONCE(rlim[RLIMIT_STACK].rlim_cur))
 		return -ENOMEM;
 
 	/* mlock limit tests */
@@ -2151,17 +2165,30 @@ static int acct_stack_growth(struct vm_a
 int expand_upwards(struct vm_area_struct *vma, unsigned long address)
 {
 	struct mm_struct *mm = vma->vm_mm;
+	struct vm_area_struct *next;
+	unsigned long gap_addr;
 	int error = 0;
 
 	if (!(vma->vm_flags & VM_GROWSUP))
 		return -EFAULT;
 
 	/* Guard against wrapping around to address 0. */
-	if (address < PAGE_ALIGN(address+4))
-		address = PAGE_ALIGN(address+4);
-	else
+	address &= PAGE_MASK;
+	address += PAGE_SIZE;
+	if (!address)
 		return -ENOMEM;
 
+	/* Enforce stack_guard_gap */
+	gap_addr = address + stack_guard_gap;
+	if (gap_addr < address)
+		return -ENOMEM;
+	next = vma->vm_next;
+	if (next && next->vm_start < gap_addr) {
+		if (!(next->vm_flags & VM_GROWSUP))
+			return -ENOMEM;
+		/* Check that both stack segments have the same anon_vma? */
+	}
+
 	/* We must make sure the anon_vma is allocated. */
 	if (unlikely(anon_vma_prepare(vma)))
 		return -ENOMEM;
@@ -2206,7 +2233,7 @@ int expand_upwards(struct vm_area_struct
 				if (vma->vm_next)
 					vma_gap_update(vma->vm_next);
 				else
-					mm->highest_vm_end = address;
+					mm->highest_vm_end = vm_end_gap(vma);
 				spin_unlock(&mm->page_table_lock);
 
 				perf_event_mmap(vma);
@@ -2227,6 +2254,8 @@ int expand_downwards(struct vm_area_stru
 				   unsigned long address)
 {
 	struct mm_struct *mm = vma->vm_mm;
+	struct vm_area_struct *prev;
+	unsigned long gap_addr;
 	int error;
 
 	address &= PAGE_MASK;
@@ -2234,6 +2263,17 @@ int expand_downwards(struct vm_area_stru
 	if (error)
 		return error;
 
+	/* Enforce stack_guard_gap */
+	gap_addr = address - stack_guard_gap;
+	if (gap_addr > address)
+		return -ENOMEM;
+	prev = vma->vm_prev;
+	if (prev && prev->vm_end > gap_addr) {
+		if (!(prev->vm_flags & VM_GROWSDOWN))
+			return -ENOMEM;
+		/* Check that both stack segments have the same anon_vma? */
+	}
+
 	/* We must make sure the anon_vma is allocated. */
 	if (unlikely(anon_vma_prepare(vma)))
 		return -ENOMEM;
@@ -2289,28 +2329,25 @@ int expand_downwards(struct vm_area_stru
 	return error;
 }
 
-/*
- * Note how expand_stack() refuses to expand the stack all the way to
- * abut the next virtual mapping, *unless* that mapping itself is also
- * a stack mapping. We want to leave room for a guard page, after all
- * (the guard page itself is not added here, that is done by the
- * actual page faulting logic)
- *
- * This matches the behavior of the guard page logic (see mm/memory.c:
- * check_stack_guard_page()), which only allows the guard page to be
- * removed under these circumstances.
- */
+/* enforced gap between the expanding stack and other mappings. */
+unsigned long stack_guard_gap = 256UL<<PAGE_SHIFT;
+
+static int __init cmdline_parse_stack_guard_gap(char *p)
+{
+	unsigned long val;
+	char *endptr;
+
+	val = simple_strtoul(p, &endptr, 10);
+	if (!*endptr)
+		stack_guard_gap = val << PAGE_SHIFT;
+
+	return 0;
+}
+__setup("stack_guard_gap=", cmdline_parse_stack_guard_gap);
+
 #ifdef CONFIG_STACK_GROWSUP
 int expand_stack(struct vm_area_struct *vma, unsigned long address)
 {
-	struct vm_area_struct *next;
-
-	address &= PAGE_MASK;
-	next = vma->vm_next;
-	if (next && next->vm_start == address + PAGE_SIZE) {
-		if (!(next->vm_flags & VM_GROWSUP))
-			return -ENOMEM;
-	}
 	return expand_upwards(vma, address);
 }
 
@@ -2332,14 +2369,6 @@ find_extend_vma(struct mm_struct *mm, un
 #else
 int expand_stack(struct vm_area_struct *vma, unsigned long address)
 {
-	struct vm_area_struct *prev;
-
-	address &= PAGE_MASK;
-	prev = vma->vm_prev;
-	if (prev && prev->vm_end == address) {
-		if (!(prev->vm_flags & VM_GROWSDOWN))
-			return -ENOMEM;
-	}
 	return expand_downwards(vma, address);
 }
 
@@ -2437,7 +2466,7 @@ detach_vmas_to_be_unmapped(struct mm_str
 		vma->vm_prev = prev;
 		vma_gap_update(vma);
 	} else
-		mm->highest_vm_end = prev ? prev->vm_end : 0;
+		mm->highest_vm_end = prev ? vm_end_gap(prev) : 0;
 	tail_vma->vm_next = NULL;
 
 	/* Kill the cache */

Re: [PATCH 4.4 00/30] 4.4.74-stable review

[Guenter Roeck]

On 06/19/2017 08:20 AM, Greg Kroah-Hartman wrote:
> This is the start of the stable review cycle for the 4.4.74 release.
> There are 30 patches in this series, all will be posted as a response
> to this one.  If anyone has any issues with these being applied, please
> let me know.
> 
> Responses should be made by Wed Jun 21 15:20:21 UTC 2017.
> Anything received after that time might be too late.
> 

Build results:
	total: 145 pass: 145 fail: 0
Qemu test results:
	total: 115 pass: 115 fail: 0

Details are available at http://kerneltests.org/builders.

Guenter

Re: [PATCH 4.4 30/30] mm: larger stack guard gap, between vmas

[Hugh Dickins]

On Mon, 19 Jun 2017, Greg Kroah-Hartman wrote:

> 4.4-stable review patch.  If anyone has any objections, please let me know.
> 
> ------------------
> 
> From: Hugh Dickins <hughd@google.com>
> 
> commit 1be7107fbe18eed3e319a6c3e83c78254b693acb upstream.

The 4.11 and 4.9 patches are fine, but I noticed a couple of corrections
to this 4.4 one.  There are very unlikely circumstances (on VM_GROWSUP
architectures only) in which that "highest_vm_end = end" line would be
wrong: several different ways to fix it, I'm tending to go with Andrea's
observation that the only need for update has already been done above,
so just VM_WARN_ON if it's unexpected.

Hugh

diff -purN 404n/include/linux/mm.h 404h/include/linux/mm.h
--- 404n/include/linux/mm.h	2017-06-20 16:48:17.162770068 -0700
+++ 404h/include/linux/mm.h	2017-06-20 17:36:35.871975695 -0700
@@ -1283,6 +1283,8 @@ static inline bool vma_is_anonymous(stru
 	return !vma->vm_ops;
 }
 
+int vma_is_stack_for_task(struct vm_area_struct *vma, struct task_struct *t);
+
 extern unsigned long move_page_tables(struct vm_area_struct *vma,
 		unsigned long old_addr, struct vm_area_struct *new_vma,
 		unsigned long new_addr, unsigned long len,
diff -purN 404n/mm/mmap.c 404h/mm/mmap.c
--- 404n/mm/mmap.c	2017-06-20 16:48:17.166770032 -0700
+++ 404h/mm/mmap.c	2017-06-20 17:42:31.312682716 -0700
@@ -923,7 +923,7 @@ again:			remove_next = 1 + (end > next->
 		else if (next)
 			vma_gap_update(next);
 		else
-			mm->highest_vm_end = end;
+			VM_WARN_ON(mm->highest_vm_end != vm_end_gap(vma));
 	}
 	if (insert && file)
 		uprobe_mmap(insert);

Re: [PATCH 4.4 30/30] mm: larger stack guard gap, between vmas

[Greg Kroah-Hartman]

On Tue, Jun 20, 2017 at 10:41:01PM -0700, Hugh Dickins wrote:
> On Mon, 19 Jun 2017, Greg Kroah-Hartman wrote:
> 
> > 4.4-stable review patch.  If anyone has any objections, please let me know.
> > 
> > ------------------
> > 
> > From: Hugh Dickins <hughd@google.com>
> > 
> > commit 1be7107fbe18eed3e319a6c3e83c78254b693acb upstream.
> 
> The 4.11 and 4.9 patches are fine, but I noticed a couple of corrections
> to this 4.4 one.  There are very unlikely circumstances (on VM_GROWSUP
> architectures only) in which that "highest_vm_end = end" line would be
> wrong: several different ways to fix it, I'm tending to go with Andrea's
> observation that the only need for update has already been done above,
> so just VM_WARN_ON if it's unexpected.
> 
> Hugh
> 
> diff -purN 404n/include/linux/mm.h 404h/include/linux/mm.h
> --- 404n/include/linux/mm.h	2017-06-20 16:48:17.162770068 -0700
> +++ 404h/include/linux/mm.h	2017-06-20 17:36:35.871975695 -0700
> @@ -1283,6 +1283,8 @@ static inline bool vma_is_anonymous(stru
>  	return !vma->vm_ops;
>  }
>  
> +int vma_is_stack_for_task(struct vm_area_struct *vma, struct task_struct *t);
> +
>  extern unsigned long move_page_tables(struct vm_area_struct *vma,
>  		unsigned long old_addr, struct vm_area_struct *new_vma,
>  		unsigned long new_addr, unsigned long len,
> diff -purN 404n/mm/mmap.c 404h/mm/mmap.c
> --- 404n/mm/mmap.c	2017-06-20 16:48:17.166770032 -0700
> +++ 404h/mm/mmap.c	2017-06-20 17:42:31.312682716 -0700
> @@ -923,7 +923,7 @@ again:			remove_next = 1 + (end > next->
>  		else if (next)
>  			vma_gap_update(next);
>  		else
> -			mm->highest_vm_end = end;
> +			VM_WARN_ON(mm->highest_vm_end != vm_end_gap(vma));
>  	}
>  	if (insert && file)
>  		uprobe_mmap(insert);

Thank you, the first chunk was already in my updated tree, and I have
now added the second chunk and will run it through the 0-day tests to
see how it goes...

greg k-h

Re: [PATCH 4.4 16/30] [media] pvrusb2: reduce stack usage pvr2_eeprom_analyze()

[Ben Hutchings]

On Mon, 2017-06-19 at 23:20 +0800, Greg Kroah-Hartman wrote:
> 4.4-stable review patch.  If anyone has any objections, please let me know.
> 
> ------------------
> 
> From: Arnd Bergmann <arnd@arndb.de>
> 
> commit 6830733d53a4517588e56227b9c8538633f0c496 upstream.
> 
> The driver uses a relatively large data structure on the stack, which
> showed up on my radar as we get a warning with the "latent entropy"
> GCC plugin:
> 
> drivers/media/usb/pvrusb2/pvrusb2-eeprom.c:153:1: error: the frame size of 1376 bytes is larger than 1152 bytes [-Werror=frame-larger-than=]
> 
> The warning is usually hidden as we raise the warning limit to 2048
> when the plugin is enabled, but I'd like to lower that again in the
> future, and making this function smaller helps to do that without
> build regressions.
> 
> Further analysis shows that putting an 'i2c_client' structure on
> the stack is not really supported, as the embedded 'struct device'
> is not initialized here, and we are only saved by the fact that
> the function that is called here does not use the pointer at all.
[...]

That is not true in 4.4-stable.  This commit depends on:

commit 6037b3ca28f4258d913dbe77248fd77827702ae3
Author: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Date:   Wed Nov 16 14:21:48 2016 -0200

    [media] tveeprom: print log messages using pr_foo()

Ben.

-- 
Ben Hutchings
Software Developer, Codethink Ltd.

Re: [PATCH 4.4 22/30] USB: gadgetfs, dummy-hcd, net2280: fix locking for callbacks

[Ben Hutchings]

On Mon, 2017-06-19 at 23:20 +0800, Greg Kroah-Hartman wrote:
> 4.4-stable review patch.  If anyone has any objections, please let me know.
> 
> ------------------
> 
> From: Alan Stern <stern@rowland.harvard.edu>
> 
> commit f16443a034c7aa359ddf6f0f9bc40d01ca31faea upstream.
[...]
> The result of this race, as seen above, is that set_link_state() can
> invoke a callback in gadgetfs even after gadgetfs has been unbound
> from dummy_hcd's UDC and its private data structures have been
> deallocated.
> 
> include/linux/usb/gadget.h documents that the ->reset, ->disconnect,
> ->suspend, and ->resume callbacks may be invoked in interrupt context.
> In general this is necessary, to prevent races with gadget driver
> removal.  This patch fixes dummy_hcd to retain the spinlock across
> these calls, and it adds a spinlock acquisition to dummy_udc_stop() to
> prevent the race.
> 
> The net2280 driver makes the same mistake of dropping the private
> spinlock for its ->disconnect and ->reset callback invocations.  The
> patch fixes it too.
[...]

Why only these two drivers?  Most of the other UDC drivers seem to do
the same thing.

Ben.

-- 
Ben Hutchings
Software Developer, Codethink Ltd.

Re: [PATCH 4.4 24/30] swap: cond_resched in swap_cgroup_prepare()

[Ben Hutchings]

On Mon, 2017-06-19 at 23:20 +0800, Greg Kroah-Hartman wrote:
> 4.4-stable review patch.  If anyone has any objections, please let me know.
> 
> ------------------
> 
> From: Yu Zhao <yuzhao@google.com>
> 
> commit ef70762948dde012146926720b70e79736336764 upstream.
> 
> I saw need_resched() warnings when swapping on large swapfile (TBs)
> because continuously allocating many pages in swap_cgroup_prepare() took
> too long.
> 
> We already cond_resched when freeing page in swap_cgroup_swapoff().  Do
> the same for the page allocation.
[...]

That seems to imply that this should also go into stable branches:

commit 460bcec84e11c75122ace5976214abbc596eb91b
Author: David Rientjes <rientjes@google.com>
Date:   Fri Apr 7 16:05:00 2017 -0700

    mm, swap_cgroup: reschedule when neeed in swap_cgroup_swapoff()
    
Ben.

-- 
Ben Hutchings
Software Developer, Codethink Ltd.

Re: [PATCH 4.4 22/30] USB: gadgetfs, dummy-hcd, net2280: fix locking for callbacks

[Alan Stern]

On Thu, 29 Jun 2017, Ben Hutchings wrote:

> On Mon, 2017-06-19 at 23:20 +0800, Greg Kroah-Hartman wrote:
> > 4.4-stable review patch.  If anyone has any objections, please let me know.
> > 
> > ------------------
> > 
> > From: Alan Stern <stern@rowland.harvard.edu>
> > 
> > commit f16443a034c7aa359ddf6f0f9bc40d01ca31faea upstream.
> [...]
> > The result of this race, as seen above, is that set_link_state() can
> > invoke a callback in gadgetfs even after gadgetfs has been unbound
> > from dummy_hcd's UDC and its private data structures have been
> > deallocated.
> > 
> > include/linux/usb/gadget.h documents that the ->reset, ->disconnect,
> > ->suspend, and ->resume callbacks may be invoked in interrupt context.
> > In general this is necessary, to prevent races with gadget driver
> > removal.  This patch fixes dummy_hcd to retain the spinlock across
> > these calls, and it adds a spinlock acquisition to dummy_udc_stop() to
> > prevent the race.
> > 
> > The net2280 driver makes the same mistake of dropping the private
> > spinlock for its ->disconnect and ->reset callback invocations.  The
> > patch fixes it too.
> [...]
> 
> Why only these two drivers?  Most of the other UDC drivers seem to do
> the same thing.

I'm not at all familiar with the other UDC drivers, only those two.

If the maintainers for other UDC drivers would like to discuss the
problem and consider whether changes are needed, I'd be glad to help.

Alan Stern

Re: [PATCH 4.4 24/30] swap: cond_resched in swap_cgroup_prepare()

[Greg Kroah-Hartman]

On Thu, Jun 29, 2017 at 06:23:43PM +0100, Ben Hutchings wrote:
> On Mon, 2017-06-19 at 23:20 +0800, Greg Kroah-Hartman wrote:
> > 4.4-stable review patch.  If anyone has any objections, please let me know.
> > 
> > ------------------
> > 
> > From: Yu Zhao <yuzhao@google.com>
> > 
> > commit ef70762948dde012146926720b70e79736336764 upstream.
> > 
> > I saw need_resched() warnings when swapping on large swapfile (TBs)
> > because continuously allocating many pages in swap_cgroup_prepare() took
> > too long.
> > 
> > We already cond_resched when freeing page in swap_cgroup_swapoff().  Do
> > the same for the page allocation.
> [...]
> 
> That seems to imply that this should also go into stable branches:
> 
> commit 460bcec84e11c75122ace5976214abbc596eb91b
> Author: David Rientjes <rientjes@google.com>
> Date:   Fri Apr 7 16:05:00 2017 -0700
> 
>     mm, swap_cgroup: reschedule when neeed in swap_cgroup_swapoff()
>     

Looks like it to me, thanks, now queued up.

greg k-h

Re: [PATCH 4.4 16/30] [media] pvrusb2: reduce stack usage pvr2_eeprom_analyze()

[Greg Kroah-Hartman]

On Thu, Jun 29, 2017 at 05:15:17PM +0100, Ben Hutchings wrote:
> On Mon, 2017-06-19 at 23:20 +0800, Greg Kroah-Hartman wrote:
> > 4.4-stable review patch.  If anyone has any objections, please let me know.
> > 
> > ------------------
> > 
> > From: Arnd Bergmann <arnd@arndb.de>
> > 
> > commit 6830733d53a4517588e56227b9c8538633f0c496 upstream.
> > 
> > The driver uses a relatively large data structure on the stack, which
> > showed up on my radar as we get a warning with the "latent entropy"
> > GCC plugin:
> > 
> > drivers/media/usb/pvrusb2/pvrusb2-eeprom.c:153:1: error: the frame size of 1376 bytes is larger than 1152 bytes [-Werror=frame-larger-than=]
> > 
> > The warning is usually hidden as we raise the warning limit to 2048
> > when the plugin is enabled, but I'd like to lower that again in the
> > future, and making this function smaller helps to do that without
> > build regressions.
> > 
> > Further analysis shows that putting an 'i2c_client' structure on
> > the stack is not really supported, as the embedded 'struct device'
> > is not initialized here, and we are only saved by the fact that
> > the function that is called here does not use the pointer at all.
> [...]
> 
> That is not true in 4.4-stable.  This commit depends on:
> 
> commit 6037b3ca28f4258d913dbe77248fd77827702ae3
> Author: Mauro Carvalho Chehab <mchehab@s-opensource.com>
> Date:   Wed Nov 16 14:21:48 2016 -0200
> 
>     [media] tveeprom: print log messages using pr_foo()

It does?  I don't understand how the two are connected.  Removing
i2c_client off of the stack is a good thing.  Ah, I see how the pointer
is used in tveeprom_hauppauge_analog(), but this shouldn't matter here,
right?

thanks,

greg k-h

Re: [PATCH 4.4 16/30] [media] pvrusb2: reduce stack usage pvr2_eeprom_analyze()

[Arnd Bergmann]

On Mon, Jul 3, 2017 at 9:31 AM, Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
> On Thu, Jun 29, 2017 at 05:15:17PM +0100, Ben Hutchings wrote:
>> On Mon, 2017-06-19 at 23:20 +0800, Greg Kroah-Hartman wrote:
>> > 4.4-stable review patch.  If anyone has any objections, please let me know.
>> >
>> > From: Arnd Bergmann <arnd@arndb.de>
>> >
>> > commit 6830733d53a4517588e56227b9c8538633f0c496 upstream.
>> >
>> > The driver uses a relatively large data structure on the stack, which
>> > showed up on my radar as we get a warning with the "latent entropy"
>> > GCC plugin:
>> >
>> > drivers/media/usb/pvrusb2/pvrusb2-eeprom.c:153:1: error: the frame size of 1376 bytes is larger than 1152 bytes [-Werror=frame-larger-than=]
>> >
>> > The warning is usually hidden as we raise the warning limit to 2048
>> > when the plugin is enabled, but I'd like to lower that again in the
>> > future, and making this function smaller helps to do that without
>> > build regressions.
>> >
>> > Further analysis shows that putting an 'i2c_client' structure on
>> > the stack is not really supported, as the embedded 'struct device'
>> > is not initialized here, and we are only saved by the fact that
>> > the function that is called here does not use the pointer at all.
>> [...]
>>
>> That is not true in 4.4-stable.  This commit depends on:
>>
>> commit 6037b3ca28f4258d913dbe77248fd77827702ae3
>> Author: Mauro Carvalho Chehab <mchehab@s-opensource.com>
>> Date:   Wed Nov 16 14:21:48 2016 -0200
>>
>>     [media] tveeprom: print log messages using pr_foo()
>
> It does?  I don't understand how the two are connected.  Removing
> i2c_client off of the stack is a good thing.  Ah, I see how the pointer
> is used in tveeprom_hauppauge_analog(), but this shouldn't matter here,
> right?

My reading of the two patches is that we actually need at least one
of them to avoid interpreting uninitialized dev->class/bus:  With just my
6830733d53a patch, we replace the uninitialized data with a NULL
pointer, which is handled gracefully in __dev_printk(), while the
6037b3ca28 patch by itself will avoid using the 'dev' pointer completely,
and give a saner output (no "(NULL device)" string or worse).

I think we probably want both of them backported to 4.4, but I don't see a
dependency between them.

        Arnd

Re: [PATCH 4.4 16/30] [media] pvrusb2: reduce stack usage pvr2_eeprom_analyze()

[Ben Hutchings]

On Mon, 2017-07-03 at 09:47 +0200, Arnd Bergmann wrote:
> On Mon, Jul 3, 2017 at 9:31 AM, Greg Kroah-Hartman
> <gregkh@linuxfoundation.org> wrote:
> > On Thu, Jun 29, 2017 at 05:15:17PM +0100, Ben Hutchings wrote:
> >> On Mon, 2017-06-19 at 23:20 +0800, Greg Kroah-Hartman wrote:
> >> > 4.4-stable review patch.  If anyone has any objections, please let me know.
> >> >
> >> > From: Arnd Bergmann <arnd@arndb.de>
> >> >
> >> > commit 6830733d53a4517588e56227b9c8538633f0c496 upstream.
[...]
> >> > Further analysis shows that putting an 'i2c_client' structure on
> >> > the stack is not really supported, as the embedded 'struct device'
> >> > is not initialized here, and we are only saved by the fact that
> >> > the function that is called here does not use the pointer at all.
> >> [...]
> >>
> >> That is not true in 4.4-stable.  This commit depends on:
> >>
> >> commit 6037b3ca28f4258d913dbe77248fd77827702ae3
> >> Author: Mauro Carvalho Chehab <mchehab@s-opensource.com>
> >> Date:   Wed Nov 16 14:21:48 2016 -0200
> >>
> >>     [media] tveeprom: print log messages using pr_foo()
> >
> > It does?  I don't understand how the two are connected.  Removing
> > i2c_client off of the stack is a good thing.  Ah, I see how the pointer
> > is used in tveeprom_hauppauge_analog(), but this shouldn't matter here,
> > right?
> 
> My reading of the two patches is that we actually need at least one
> of them to avoid interpreting uninitialized dev->class/bus:  With just my
> 6830733d53a patch, we replace the uninitialized data with a NULL
> pointer, which is handled gracefully in __dev_printk(), while the
> 6037b3ca28 patch by itself will avoid using the 'dev' pointer completely,
> and give a saner output (no "(NULL device)" string or worse).
> 
> I think we probably want both of them backported to 4.4, but I don't see a
> dependency between them.

Sorry, I mixed up two commits.  The one actually needed to avoid a null
dereference is:

commit 7cda4c5bae46ffca3abeadc4c1882d9325ee3102
Author: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Date:   Thu Oct 13 10:51:20 2016 -0300

    [media] tveeprom: use dev_foo() for printk messages

Then "[media] tveeprom: print log messages using pr_foo()" is cleanup on
top of that.

Ben.

-- 
Ben Hutchings
Software Developer, Codethink Ltd.

Re: [PATCH 4.4 16/30] [media] pvrusb2: reduce stack usage pvr2_eeprom_analyze()

[Arnd Bergmann]

On Mon, Jul 3, 2017 at 3:37 PM, Ben Hutchings
<ben.hutchings@codethink.co.uk> wrote:
> On Mon, 2017-07-03 at 09:47 +0200, Arnd Bergmann wrote:
>> On Mon, Jul 3, 2017 at 9:31 AM, Greg Kroah-Hartman
>>
>> I think we probably want both of them backported to 4.4, but I don't see a
>> dependency between them.
>
> Sorry, I mixed up two commits.  The one actually needed to avoid a null
> dereference is:
>
> commit 7cda4c5bae46ffca3abeadc4c1882d9325ee3102
> Author: Mauro Carvalho Chehab <mchehab@s-opensource.com>
> Date:   Thu Oct 13 10:51:20 2016 -0300
>
>     [media] tveeprom: use dev_foo() for printk messages
>
> Then "[media] tveeprom: print log messages using pr_foo()" is cleanup on
> top of that.

Ah, I see now. We do indeed need both of Mauro's patches before we
can apply mine then.

        Arnd