[PATCH AUTOSEL 5.10 03/10] scsi: megaraid_sas: Fix for a potential deadlock

Sasha Levin
2024-12-11T18:54:25Z

From: Tomas Henzl <thenzl@redhat.com>

[ Upstream commit 50740f4dc78b41dec7c8e39772619d5ba841ddd7 ]

This fixes a 'possible circular locking dependency detected' warning
CPU0 CPU1
---- ----
lock(&instance->reset_mutex);
lock(&shost->scan_mutex);
lock(&instance->reset_mutex);
lock(&shost->scan_mutex);

Fix this by temporarily releasing the reset_mutex.

Signed-off-by: Tomas Henzl <thenzl@redhat.com>
Link: https://lore.kernel.org/r/20240923174833.45345-1-thenzl@redhat.com
Acked-by: Chandrakanth Patil <chandrakanth.patil@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/scsi/megaraid/megaraid_sas_base.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c b/drivers/scsi/megaraid/megaraid_sas_base.c
index 365279d7c9829..d709d261d0ad1 100644
--- a/drivers/scsi/megaraid/megaraid_sas_base.c
+++ b/drivers/scsi/megaraid/megaraid_sas_base.c
@@ -8868,8 +8868,11 @@ megasas_aen_polling(struct work_struct *work)
(ld_target_id / MEGASAS_MAX_DEV_PER_CHANNEL),
(ld_target_id - MEGASAS_MAX_DEV_PER_CHANNEL),
0);
- if (sdev1)
+ if (sdev1) {
+ mutex_unlock(&instance->reset_mutex);
megasas_remove_scsi_device(sdev1);
+ mutex_lock(&instance->reset_mutex);
+ }

event_type = SCAN_VD_CHANNEL;
break;
--
2.43.0