* [PATCH] scsi: lpfc: Fix a possible data race in lpfc_unregister_fcf_rescan()
@ 2023-06-30 2:47 Tuo Li
2023-07-04 16:14 ` Justin Tee
2023-07-05 14:35 ` Laurence Oberman
0 siblings, 2 replies; 3+ messages in thread
From: Tuo Li @ 2023-06-30 2:47 UTC (permalink / raw)
To: james.smart, dick.kennedy, jejb, martin.petersen
Cc: linux-scsi, linux-kernel, baijiaju1990, Tuo Li, BassCheck
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
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] scsi: lpfc: Fix a possible data race in lpfc_unregister_fcf_rescan()
2023-06-30 2:47 [PATCH] scsi: lpfc: Fix a possible data race in lpfc_unregister_fcf_rescan() Tuo Li
@ 2023-07-04 16:14 ` Justin Tee
2023-07-05 14:35 ` Laurence Oberman
1 sibling, 0 replies; 3+ messages in thread
From: Justin Tee @ 2023-07-04 16:14 UTC (permalink / raw)
To: Tuo Li
Cc: james.smart, dick.kennedy, jejb, martin.petersen, linux-scsi,
linux-kernel, baijiaju1990, BassCheck, Justin Tee
Hi Tuo,
Looks good.
Reviewed-by: Justin Tee <justin.tee@broadcom.com>
Thanks,
Justin
On Thu, Jun 29, 2023 at 8:03 PM Tuo Li <islituo@gmail.com> wrote:
>
> 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
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] scsi: lpfc: Fix a possible data race in lpfc_unregister_fcf_rescan()
2023-06-30 2:47 [PATCH] scsi: lpfc: Fix a possible data race in lpfc_unregister_fcf_rescan() Tuo Li
2023-07-04 16:14 ` Justin Tee
@ 2023-07-05 14:35 ` Laurence Oberman
1 sibling, 0 replies; 3+ messages in thread
From: Laurence Oberman @ 2023-07-05 14:35 UTC (permalink / raw)
To: Tuo Li, james.smart, dick.kennedy, jejb, martin.petersen
Cc: linux-scsi, linux-kernel, baijiaju1990, BassCheck
On Fri, 2023-06-30 at 10:47 +0800, Tuo Li wrote:
> 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;
>
> /*
This makes sense and looks good to me
Reviewed-by: Laurence Oberman <loberman@redhat.com>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2023-06-30 2:47 [PATCH] scsi: lpfc: Fix a possible data race in lpfc_unregister_fcf_rescan() Tuo Li
2023-07-04 16:14 ` Justin Tee
2023-07-05 14:35 ` Laurence Oberman
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