[PATCH AUTOSEL 6.1 1/5] scsi: lpfc: Fix a possible data race in lpfc_unregister_fcf_rescan()

From: Sasha Levin
Date: Thu Aug 03 2023 - 09:04:07 EST


From: Tuo Li <islituo@xxxxxxxxx>

[ Upstream commit 0e881c0a4b6146b7e856735226208f48251facd8 ]

The variable phba->fcf.fcf_flag is often protected by the lock
phba->hbalock() when is accessed. Here is an example in
lpfc_unregister_fcf_rescan():

spin_lock_irq(&phba->hbalock);
phba->fcf.fcf_flag |= FCF_INIT_DISC;
spin_unlock_irq(&phba->hbalock);

However, in the same function, phba->fcf.fcf_flag is assigned with 0
without holding the lock, and thus can cause a data race:

phba->fcf.fcf_flag = 0;

To fix this possible data race, a lock and unlock pair is added when
accessing the variable phba->fcf.fcf_flag.

Reported-by: BassCheck <bass@xxxxxxxxxxx>
Signed-off-by: Tuo Li <islituo@xxxxxxxxx>
Link: https://lore.kernel.org/r/20230630024748.1035993-1-islituo@xxxxxxxxx
Reviewed-by: Justin Tee <justin.tee@xxxxxxxxxxxx>
Reviewed-by: Laurence Oberman <loberman@xxxxxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/scsi/lpfc/lpfc_hbadisc.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/scsi/lpfc/lpfc_hbadisc.c b/drivers/scsi/lpfc/lpfc_hbadisc.c
index d38ebd7281b9b..326ef4942e672 100644
--- a/drivers/scsi/lpfc/lpfc_hbadisc.c
+++ b/drivers/scsi/lpfc/lpfc_hbadisc.c
@@ -6960,7 +6960,9 @@ lpfc_unregister_fcf_rescan(struct lpfc_hba *phba)
if (rc)
return;
/* Reset HBA FCF states after successful unregister FCF */
+ spin_lock_irq(&phba->hbalock);
phba->fcf.fcf_flag = 0;
+ spin_unlock_irq(&phba->hbalock);
phba->fcf.current_rec.flag = 0;

/*
--
2.40.1