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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Brian Bunker <brian@purestorage.com>,
	Jitendra Khasdev <jitendra.khasdev@oracle.com>,
	Hannes Reinecke <hare@suse.de>,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.9 34/78] scsi: scsi_dh_alua: Avoid crash during alua_bus_detach()
Date: Tue, 17 Nov 2020 14:05:00 +0100	[thread overview]
Message-ID: <20201117122110.773594142@linuxfoundation.org> (raw)
In-Reply-To: <20201117122109.116890262@linuxfoundation.org>

From: Hannes Reinecke <hare@suse.de>

[ Upstream commit 5faf50e9e9fdc2117c61ff7e20da49cd6a29e0ca ]

alua_bus_detach() might be running concurrently with alua_rtpg_work(), so
we might trip over h->sdev == NULL and call BUG_ON().  The correct way of
handling it is to not set h->sdev to NULL in alua_bus_detach(), and call
rcu_synchronize() before the final delete to ensure that all concurrent
threads have left the critical section.  Then we can get rid of the
BUG_ON() and replace it with a simple if condition.

Link: https://lore.kernel.org/r/1600167537-12509-1-git-send-email-jitendra.khasdev@oracle.com
Link: https://lore.kernel.org/r/20200924104559.26753-1-hare@suse.de
Cc: Brian Bunker <brian@purestorage.com>
Acked-by: Brian Bunker <brian@purestorage.com>
Tested-by: Jitendra Khasdev <jitendra.khasdev@oracle.com>
Reviewed-by: Jitendra Khasdev <jitendra.khasdev@oracle.com>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/scsi/device_handler/scsi_dh_alua.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index 60c288526355a..2bc3dc6244a5e 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -657,8 +657,8 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg)
 					rcu_read_lock();
 					list_for_each_entry_rcu(h,
 						&tmp_pg->dh_list, node) {
-						/* h->sdev should always be valid */
-						BUG_ON(!h->sdev);
+						if (!h->sdev)
+							continue;
 						h->sdev->access_state = desc[0];
 					}
 					rcu_read_unlock();
@@ -704,7 +704,8 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg)
 			pg->expiry = 0;
 			rcu_read_lock();
 			list_for_each_entry_rcu(h, &pg->dh_list, node) {
-				BUG_ON(!h->sdev);
+				if (!h->sdev)
+					continue;
 				h->sdev->access_state =
 					(pg->state & SCSI_ACCESS_STATE_MASK);
 				if (pg->pref)
@@ -1149,7 +1150,6 @@ static void alua_bus_detach(struct scsi_device *sdev)
 	spin_lock(&h->pg_lock);
 	pg = h->pg;
 	rcu_assign_pointer(h->pg, NULL);
-	h->sdev = NULL;
 	spin_unlock(&h->pg_lock);
 	if (pg) {
 		spin_lock_irq(&pg->lock);
@@ -1158,6 +1158,7 @@ static void alua_bus_detach(struct scsi_device *sdev)
 		kref_put(&pg->kref, release_port_group);
 	}
 	sdev->handler_data = NULL;
+	synchronize_rcu();
 	kfree(h);
 }
 
-- 
2.27.0




  parent reply	other threads:[~2020-11-17 13:11 UTC|newest]

Thread overview: 82+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-17 13:04 [PATCH 4.9 00/78] 4.9.244-rc1 review Greg Kroah-Hartman
2020-11-17 13:04 ` [PATCH 4.9 01/78] regulator: defer probe when trying to get voltage from unresolved supply Greg Kroah-Hartman
2020-11-17 13:04 ` [PATCH 4.9 02/78] ring-buffer: Fix recursion protection transitions between interrupt context Greg Kroah-Hartman
2020-11-17 13:04 ` [PATCH 4.9 03/78] gfs2: Wake up when sd_glock_disposal becomes zero Greg Kroah-Hartman
2020-11-17 13:04 ` [PATCH 4.9 04/78] mm: mempolicy: fix potential pte_unmap_unlock pte error Greg Kroah-Hartman
2020-11-17 13:04 ` [PATCH 4.9 05/78] time: Prevent undefined behaviour in timespec64_to_ns() Greg Kroah-Hartman
2020-11-17 13:04 ` [PATCH 4.9 06/78] btrfs: reschedule when cloning lots of extents Greg Kroah-Hartman
2020-11-17 13:04 ` [PATCH 4.9 07/78] genirq: Let GENERIC_IRQ_IPI select IRQ_DOMAIN_HIERARCHY Greg Kroah-Hartman
2020-11-17 13:04 ` [PATCH 4.9 08/78] net: xfrm: fix a race condition during allocing spi Greg Kroah-Hartman
2020-11-17 13:04 ` [PATCH 4.9 09/78] perf tools: Add missing swap for ino_generation Greg Kroah-Hartman
2020-11-17 13:04 ` [PATCH 4.9 10/78] ALSA: hda: prevent undefined shift in snd_hdac_ext_bus_get_link() Greg Kroah-Hartman
2020-11-17 13:04 ` [PATCH 4.9 11/78] can: dev: can_get_echo_skb(): prevent call to kfree_skb() in hard IRQ context Greg Kroah-Hartman
2020-11-17 13:04 ` [PATCH 4.9 12/78] can: dev: __can_get_echo_skb(): fix real payload length return value for RTR frames Greg Kroah-Hartman
2020-11-17 13:04 ` [PATCH 4.9 13/78] can: can_create_echo_skb(): fix echo skb generation: always use skb_clone() Greg Kroah-Hartman
2020-11-17 13:04 ` [PATCH 4.9 14/78] can: peak_usb: add range checking in decode operations Greg Kroah-Hartman
2020-11-17 13:04 ` [PATCH 4.9 15/78] can: peak_usb: peak_usb_get_ts_time(): fix timestamp wrapping Greg Kroah-Hartman
2020-11-17 13:04 ` [PATCH 4.9 16/78] xfs: flush new eof page on truncate to avoid post-eof corruption Greg Kroah-Hartman
2020-11-17 13:04 ` [PATCH 4.9 17/78] Btrfs: fix missing error return if writeback for extent buffer never started Greg Kroah-Hartman
2020-11-17 13:04 ` [PATCH 4.9 18/78] pinctrl: devicetree: Avoid taking direct reference to device name string Greg Kroah-Hartman
2020-11-17 13:04 ` [PATCH 4.9 19/78] i40e: Fix a potential NULL pointer dereference Greg Kroah-Hartman
2020-11-17 13:04 ` [PATCH 4.9 20/78] i40e: add num_vectors checker in iwarp handler Greg Kroah-Hartman
2020-11-17 13:04 ` [PATCH 4.9 21/78] i40e: Wrong truncation from u16 to u8 Greg Kroah-Hartman
2020-11-17 13:04 ` [PATCH 4.9 22/78] i40e: Fix of memory leak and integer truncation in i40e_virtchnl.c Greg Kroah-Hartman
2020-11-17 13:04 ` [PATCH 4.9 23/78] i40e: Memory leak in i40e_config_iwarp_qvlist Greg Kroah-Hartman
2020-11-17 13:04 ` [PATCH 4.9 24/78] geneve: add transport ports in route lookup for geneve Greg Kroah-Hartman
2020-11-17 13:04 ` [PATCH 4.9 25/78] ath9k_htc: Use appropriate rs_datalen type Greg Kroah-Hartman
2020-11-17 13:04 ` [PATCH 4.9 26/78] usb: gadget: goku_udc: fix potential crashes in probe Greg Kroah-Hartman
2020-11-17 13:04 ` [PATCH 4.9 27/78] gfs2: Free rd_bits later in gfs2_clear_rgrpd to fix use-after-free Greg Kroah-Hartman
2020-11-17 13:04 ` [PATCH 4.9 28/78] gfs2: check for live vs. read-only file system in gfs2_fitrim Greg Kroah-Hartman
2020-11-17 13:04 ` [PATCH 4.9 29/78] scsi: hpsa: Fix memory leak in hpsa_init_one() Greg Kroah-Hartman
2020-11-17 13:04 ` [PATCH 4.9 30/78] drm/amdgpu: perform srbm soft reset always on SDMA resume Greg Kroah-Hartman
2020-11-17 13:04 ` [PATCH 4.9 31/78] mac80211: fix use of skb payload instead of header Greg Kroah-Hartman
2020-11-17 13:04 ` [PATCH 4.9 32/78] mac80211: always wind down STA state Greg Kroah-Hartman
2020-11-17 13:04 ` [PATCH 4.9 33/78] cfg80211: regulatory: Fix inconsistent format argument Greg Kroah-Hartman
2020-11-17 13:05 ` Greg Kroah-Hartman [this message]
2020-11-17 13:05 ` [PATCH 4.9 35/78] iommu/amd: Increase interrupt remapping table limit to 512 entries Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 36/78] pinctrl: aspeed: Fix GPI only function problem Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 37/78] xfs: fix flags argument to rmap lookup when converting shared file rmaps Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 38/78] xfs: fix rmap key and record comparison functions Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 39/78] xfs: fix a missing unlock on error in xfs_fs_map_blocks Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 40/78] of/address: Fix of_node memory leak in of_dma_is_coherent Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 41/78] cosa: Add missing kfree in error path of cosa_write Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 42/78] perf: Fix get_recursion_context() Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 43/78] ext4: correctly report "not supported" for {usr,grp}jquota when !CONFIG_QUOTA Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 44/78] ext4: unlock xattr_sem properly in ext4_inline_data_truncate() Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 45/78] usb: cdc-acm: Add DISABLE_ECHO for Renesas USB Download mode Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 46/78] mei: protect mei_cl_mtu from null dereference Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 47/78] ocfs2: initialize ip_next_orphan Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 48/78] dont dump the threads that had been already exiting when zapped Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 49/78] drm/gma500: Fix out-of-bounds access to struct drm_device.vblank[] Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 50/78] pinctrl: amd: use higher precision for 512 RtcClk Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 51/78] pinctrl: amd: fix incorrect way to disable debounce filter Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 52/78] swiotlb: fix "x86: Dont panic if can not alloc buffer for swiotlb" Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 53/78] IPv6: Set SIT tunnel hard_header_len to zero Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 54/78] net/af_iucv: fix null pointer dereference on shutdown Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 55/78] net/x25: Fix null-ptr-deref in x25_connect Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 56/78] net: Update window_clamp if SOCK_RCVBUF is set Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 57/78] random32: make prandom_u32() output unpredictable Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 58/78] x86/speculation: Allow IBPB to be conditionally enabled on CPUs with always-on STIBP Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 59/78] perf/core: Fix bad use of igrab() Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 60/78] perf/core: Fix crash when using HW tracing kernel filters Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 61/78] perf/core: Fix a memory leak in perf_event_parse_addr_filter() Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 62/78] xen/events: avoid removing an event channel while handling it Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 63/78] xen/events: add a proper barrier to 2-level uevent unmasking Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 64/78] xen/events: fix race in evtchn_fifo_unmask() Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 65/78] xen/events: add a new "late EOI" evtchn framework Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 66/78] xen/blkback: use lateeoi irq binding Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 67/78] xen/netback: " Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 68/78] xen/scsiback: " Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 69/78] xen/pciback: " Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 70/78] xen/events: switch user event channels to lateeoi model Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 71/78] xen/events: use a common cpu hotplug hook for event channels Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 72/78] xen/events: defer eoi in case of excessive number of events Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 73/78] xen/events: block rogue events for some time Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 74/78] perf/core: Fix race in the perf_mmap_close() function Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 75/78] Revert "kernel/reboot.c: convert simple_strtoul to kstrtoint" Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 76/78] reboot: fix overflow parsing reboot cpu number Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 77/78] ext4: fix leaking sysfs kobject after failed mount Greg Kroah-Hartman
2020-11-17 13:05 ` [PATCH 4.9 78/78] Convert trailing spaces and periods in path components Greg Kroah-Hartman
2020-11-17 22:06 ` [PATCH 4.9 00/78] 4.9.244-rc1 review Shuah Khan
2020-11-18 11:14 ` Naresh Kamboju
2020-11-18 15:22 ` Guenter Roeck

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