[PATCH 0/3] pstore fixes for v4.11

[PATCH 0/3] pstore fixes for v4.11

[Kees Cook]

Here's a dump to the mailing list of the fixes landing in the pstore
tree for v4.11:

- [PATCH 1/3] pstore: Correctly initialize spinlock and flags
- [PATCH 2/3] pstore: Check for prz allocation in walker
- [PATCH 3/3] MAINTAINERS: Adjust pstore git repo URI, add files

-Kees

[PATCH 1/3] pstore: Correctly initialize spinlock and flags

[Kees Cook]

The ram backend wasn't always initializing its spinlock correctly. Since
it was coming from kzalloc memory, though, it was harmless on
architectures that initialize unlocked spinlocks to 0 (at least x86 and
ARM). This also fixes a possibly ignored flag setting too.

When running under CONFIG_DEBUG_SPINLOCK, the following Oops was visible:

[    0.760836] persistent_ram: found existing buffer, size 29988, start 29988
[    0.765112] persistent_ram: found existing buffer, size 30105, start 30105
[    0.769435] persistent_ram: found existing buffer, size 118542, start 118542
[    0.785960] persistent_ram: found existing buffer, size 0, start 0
[    0.786098] persistent_ram: found existing buffer, size 0, start 0
[    0.786131] pstore: using zlib compression
[    0.790716] BUG: spinlock bad magic on CPU#0, swapper/0/1
[    0.790729]  lock: 0xffffffc0d1ca9bb0, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
[    0.790742] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.10.0-rc2+ #913
[    0.790747] Hardware name: Google Kevin (DT)
[    0.790750] Call trace:
[    0.790768] [<ffffff900808ae88>] dump_backtrace+0x0/0x2bc
[    0.790780] [<ffffff900808b164>] show_stack+0x20/0x28
[    0.790794] [<ffffff9008460ee0>] dump_stack+0xa4/0xcc
[    0.790809] [<ffffff9008113cfc>] spin_dump+0xe0/0xf0
[    0.790821] [<ffffff9008113d3c>] spin_bug+0x30/0x3c
[    0.790834] [<ffffff9008113e28>] do_raw_spin_lock+0x50/0x1b8
[    0.790846] [<ffffff9008a2d2ec>] _raw_spin_lock_irqsave+0x54/0x6c
[    0.790862] [<ffffff90083ac3b4>] buffer_size_add+0x48/0xcc
[    0.790875] [<ffffff90083acb34>] persistent_ram_write+0x60/0x11c
[    0.790888] [<ffffff90083aab1c>] ramoops_pstore_write_buf+0xd4/0x2a4
[    0.790900] [<ffffff90083a9d3c>] pstore_console_write+0xf0/0x134
[    0.790912] [<ffffff900811c304>] console_unlock+0x48c/0x5e8
[    0.790923] [<ffffff900811da18>] register_console+0x3b0/0x4d4
[    0.790935] [<ffffff90083aa7d0>] pstore_register+0x1a8/0x234
[    0.790947] [<ffffff90083ac250>] ramoops_probe+0x6b8/0x7d4
[    0.790961] [<ffffff90085ca548>] platform_drv_probe+0x7c/0xd0
[    0.790972] [<ffffff90085c76ac>] driver_probe_device+0x1b4/0x3bc
[    0.790982] [<ffffff90085c7ac8>] __device_attach_driver+0xc8/0xf4
[    0.790996] [<ffffff90085c4bfc>] bus_for_each_drv+0xb4/0xe4
[    0.791006] [<ffffff90085c7414>] __device_attach+0xd0/0x158
[    0.791016] [<ffffff90085c7b18>] device_initial_probe+0x24/0x30
[    0.791026] [<ffffff90085c648c>] bus_probe_device+0x50/0xe4
[    0.791038] [<ffffff90085c35b8>] device_add+0x3a4/0x76c
[    0.791051] [<ffffff90087d0e84>] of_device_add+0x74/0x84
[    0.791062] [<ffffff90087d19b8>] of_platform_device_create_pdata+0xc0/0x100
[    0.791073] [<ffffff90087d1a2c>] of_platform_device_create+0x34/0x40
[    0.791086] [<ffffff900903c910>] of_platform_default_populate_init+0x58/0x78
[    0.791097] [<ffffff90080831fc>] do_one_initcall+0x88/0x160
[    0.791109] [<ffffff90090010ac>] kernel_init_freeable+0x264/0x31c
[    0.791123] [<ffffff9008a25bd0>] kernel_init+0x18/0x11c
[    0.791133] [<ffffff9008082ec0>] ret_from_fork+0x10/0x50
[    0.793717] console [pstore-1] enabled
[    0.797845] pstore: Registered ramoops as persistent store backend
[    0.804647] ramoops: attached 0x100000@0xf7edc000, ecc: 0/0

Fixes: 663deb47880f ("pstore: Allow prz to control need for locking")
Fixes: 109704492ef6 ("pstore: Make spinlock per zone instead of global")
Reported-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 fs/pstore/ram_core.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/fs/pstore/ram_core.c b/fs/pstore/ram_core.c
index a857338b7dab..bc927e30bdcc 100644
--- a/fs/pstore/ram_core.c
+++ b/fs/pstore/ram_core.c
@@ -467,8 +467,7 @@ static int persistent_ram_buffer_map(phys_addr_t start, phys_addr_t size,
 }
 
 static int persistent_ram_post_init(struct persistent_ram_zone *prz, u32 sig,
-				    struct persistent_ram_ecc_info *ecc_info,
-				    unsigned long flags)
+				    struct persistent_ram_ecc_info *ecc_info)
 {
 	int ret;
 
@@ -494,10 +493,9 @@ static int persistent_ram_post_init(struct persistent_ram_zone *prz, u32 sig,
 			 prz->buffer->sig);
 	}
 
+	/* Rewind missing or invalid memory area. */
 	prz->buffer->sig = sig;
 	persistent_ram_zap(prz);
-	prz->buffer_lock = __RAW_SPIN_LOCK_UNLOCKED(buffer_lock);
-	prz->flags = flags;
 
 	return 0;
 }
@@ -533,11 +531,15 @@ struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size,
 		goto err;
 	}
 
+	/* Initialize general buffer state. */
+	prz->buffer_lock = __RAW_SPIN_LOCK_UNLOCKED(buffer_lock);
+	prz->flags = flags;
+
 	ret = persistent_ram_buffer_map(start, size, prz, memtype);
 	if (ret)
 		goto err;
 
-	ret = persistent_ram_post_init(prz, sig, ecc_info, flags);
+	ret = persistent_ram_post_init(prz, sig, ecc_info);
 	if (ret)
 		goto err;
 
-- 
2.7.4

[PATCH 2/3] pstore: Check for prz allocation in walker

[Kees Cook]

Instead of needing additional checks in callers for unallocated przs,
perform the check in the walker, which gives us a more universal way to
handle the situation.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
 fs/pstore/ram.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index 1d887efaaf71..11f918d34b1e 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -133,7 +133,8 @@ ramoops_get_next_prz(struct persistent_ram_zone *przs[], uint *c, uint max,
 	struct persistent_ram_zone *prz;
 	int i = (*c)++;
 
-	if (i >= max)
+	/* Give up if we never existed or have hit the end. */
+	if (!przs || i >= max)
 		return NULL;
 
 	prz = przs[i];
@@ -280,7 +281,7 @@ static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
 					   1, id, type, PSTORE_TYPE_PMSG, 0);
 
 	/* ftrace is last since it may want to dynamically allocate memory. */
-	if (!prz_ok(prz) && cxt->fprzs) {
+	if (!prz_ok(prz)) {
 		if (!(cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)) {
 			prz = ramoops_get_next_prz(cxt->fprzs,
 					&cxt->ftrace_read_cnt, 1, id, type,
-- 
2.7.4

[PATCH 3/3] MAINTAINERS: Adjust pstore git repo URI, add files

[Kees Cook]

The tree used for staging pstore changes has moved to my repo. The -next
tree already pulls from here, so update MAINTAINERS to reflect reality.
While at it, add some more pstore-related files to track.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
 MAINTAINERS | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/MAINTAINERS b/MAINTAINERS
index 107c10e8f2d2..b135644f8a60 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -9968,16 +9968,19 @@ S:	Maintained
 F:	drivers/block/ps3vram.c
 
 PSTORE FILESYSTEM
+M:	Kees Cook <keescook@chromium.org>
 M:	Anton Vorontsov <anton@enomsg.org>
 M:	Colin Cross <ccross@android.com>
-M:	Kees Cook <keescook@chromium.org>
 M:	Tony Luck <tony.luck@intel.com>
 S:	Maintained
-T:	git git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux.git
+T:	git git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git for-next/pstore
 F:	fs/pstore/
 F:	include/linux/pstore*
 F:	drivers/firmware/efi/efi-pstore.c
 F:	drivers/acpi/apei/erst.c
+F:	Documentation/admin-guide/ramoops.rst
+F:	Documentation/devicetree/bindings/reserved-memory/ramoops.txt
+K:	\b(pstore|ramoops)
 
 PTP HARDWARE CLOCK SUPPORT
 M:	Richard Cochran <richardcochran@gmail.com>
-- 
2.7.4