[PATCH] scsi: lpfc: Fix a possible data race in lpfc_unregister_fcf_rescan()

Tuo Li
2023-06-30T02:48:12Z

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@buaa.edu.cn>
Signed-off-by: Tuo Li <islituo@gmail.com>
---
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 5ba3a9ad9501..9d2feb69cae7 100644
--- a/drivers/scsi/lpfc/lpfc_hbadisc.c
+++ b/drivers/scsi/lpfc/lpfc_hbadisc.c
@@ -6961,7 +6961,9 @@ 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;

/*
--
2.34.1