* [PATCH] scsi: ufs: fix livelock on ufshcd_clear_ua_wlun
@ 2020-12-16 19:02 Jaegeuk Kim
2020-12-17 1:27 ` Stanley Chu
0 siblings, 1 reply; 3+ messages in thread
From: Jaegeuk Kim @ 2020-12-16 19:02 UTC (permalink / raw)
To: linux-kernel, linux-scsi, kernel-team
Cc: cang, alim.akhtar, avri.altman, bvanassche, martin.petersen,
stanley.chu, Jaegeuk Kim
From: Jaegeuk Kim <jaegeuk@google.com>
This fixes the below livelock which is caused by calling a scsi command before
ufshcd_scsi_unblock_requests() in ufshcd_ungate_work().
Workqueue: ufs_clk_gating_0 ufshcd_ungate_work
Call trace:
__switch_to+0x298/0x2bc
__schedule+0x59c/0x760
schedule+0xac/0xf0
schedule_timeout+0x44/0x1b4
io_schedule_timeout+0x44/0x68
wait_for_common_io+0x7c/0x100
wait_for_completion_io+0x14/0x20
blk_execute_rq+0x94/0xd0
__scsi_execute+0x100/0x1c0
ufshcd_clear_ua_wlun+0x124/0x1c8
ufshcd_host_reset_and_restore+0x1d0/0x2cc
ufshcd_link_recovery+0xac/0x134
ufshcd_uic_hibern8_exit+0x1e8/0x1f0
ufshcd_ungate_work+0xac/0x130
process_one_work+0x270/0x47c
worker_thread+0x27c/0x4d8
kthread+0x13c/0x320
ret_from_fork+0x10/0x18
Fixes: 1918651f2d7e ("scsi: ufs: Clear UAC for RPMB after ufshcd resets")
Signed-off-by: Jaegeuk Kim <jaegeuk@google.com>
---
drivers/scsi/ufs/ufshcd.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index e221add25a7e..b0998db1b781 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -1603,6 +1603,7 @@ static void ufshcd_ungate_work(struct work_struct *work)
}
unblock_reqs:
ufshcd_scsi_unblock_requests(hba);
+ ufshcd_clear_ua_wluns(hba);
}
/**
@@ -6913,7 +6914,7 @@ static int ufshcd_host_reset_and_restore(struct ufs_hba *hba)
/* Establish the link again and restore the device */
err = ufshcd_probe_hba(hba, false);
- if (!err)
+ if (!err && !hba->clk_gating.is_suspended)
ufshcd_clear_ua_wluns(hba);
out:
if (err)
@@ -8745,6 +8746,7 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
ufshcd_resume_clkscaling(hba);
hba->clk_gating.is_suspended = false;
hba->dev_info.b_rpm_dev_flush_capable = false;
+ ufshcd_clear_ua_wluns(hba);
ufshcd_release(hba);
out:
if (hba->dev_info.b_rpm_dev_flush_capable) {
@@ -8855,6 +8857,8 @@ static int ufshcd_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)
cancel_delayed_work(&hba->rpm_dev_flush_recheck_work);
}
+ ufshcd_clear_ua_wluns(hba);
+
/* Schedule clock gating in case of no access to UFS device yet */
ufshcd_release(hba);
--
2.29.2.729.g45daf8777d-goog
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] scsi: ufs: fix livelock on ufshcd_clear_ua_wlun
2020-12-16 19:02 [PATCH] scsi: ufs: fix livelock on ufshcd_clear_ua_wlun Jaegeuk Kim
@ 2020-12-17 1:27 ` Stanley Chu
2020-12-17 1:41 ` Jaegeuk Kim
0 siblings, 1 reply; 3+ messages in thread
From: Stanley Chu @ 2020-12-17 1:27 UTC (permalink / raw)
To: Jaegeuk Kim
Cc: linux-kernel, linux-scsi, kernel-team, cang, alim.akhtar,
avri.altman, bvanassche, martin.petersen, Jaegeuk Kim
Hi Jaegeuk,
On Wed, 2020-12-16 at 11:02 -0800, Jaegeuk Kim wrote:
> From: Jaegeuk Kim <jaegeuk@google.com>
>
> This fixes the below livelock which is caused by calling a scsi command before
> ufshcd_scsi_unblock_requests() in ufshcd_ungate_work().
>
> Workqueue: ufs_clk_gating_0 ufshcd_ungate_work
> Call trace:
> __switch_to+0x298/0x2bc
> __schedule+0x59c/0x760
> schedule+0xac/0xf0
> schedule_timeout+0x44/0x1b4
> io_schedule_timeout+0x44/0x68
> wait_for_common_io+0x7c/0x100
> wait_for_completion_io+0x14/0x20
> blk_execute_rq+0x94/0xd0
> __scsi_execute+0x100/0x1c0
> ufshcd_clear_ua_wlun+0x124/0x1c8
> ufshcd_host_reset_and_restore+0x1d0/0x2cc
> ufshcd_link_recovery+0xac/0x134
> ufshcd_uic_hibern8_exit+0x1e8/0x1f0
> ufshcd_ungate_work+0xac/0x130
According to the latest mainstream kernel, once
ufshcd_uic_hibern8_exit() encounters error, instead, error handler work
will be scheduled without blocking ufshcd_uic_hibern8_exit(). In
addition, ufshcd_scsi_unblock_requests() would be invoked before leaving
ufshcd_uic_hibern8_exit(). So this stack is no longer existed.
Thanks,
Stanley Chu
> process_one_work+0x270/0x47c
> worker_thread+0x27c/0x4d8
> kthread+0x13c/0x320
> ret_from_fork+0x10/0x18
>
> Fixes: 1918651f2d7e ("scsi: ufs: Clear UAC for RPMB after ufshcd resets")
> Signed-off-by: Jaegeuk Kim <jaegeuk@google.com>
> ---
> drivers/scsi/ufs/ufshcd.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index e221add25a7e..b0998db1b781 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -1603,6 +1603,7 @@ static void ufshcd_ungate_work(struct work_struct *work)
> }
> unblock_reqs:
> ufshcd_scsi_unblock_requests(hba);
> + ufshcd_clear_ua_wluns(hba);
> }
>
> /**
> @@ -6913,7 +6914,7 @@ static int ufshcd_host_reset_and_restore(struct ufs_hba *hba)
>
> /* Establish the link again and restore the device */
> err = ufshcd_probe_hba(hba, false);
> - if (!err)
> + if (!err && !hba->clk_gating.is_suspended)
> ufshcd_clear_ua_wluns(hba);
> out:
> if (err)
> @@ -8745,6 +8746,7 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
> ufshcd_resume_clkscaling(hba);
> hba->clk_gating.is_suspended = false;
> hba->dev_info.b_rpm_dev_flush_capable = false;
> + ufshcd_clear_ua_wluns(hba);
> ufshcd_release(hba);
> out:
> if (hba->dev_info.b_rpm_dev_flush_capable) {
> @@ -8855,6 +8857,8 @@ static int ufshcd_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)
> cancel_delayed_work(&hba->rpm_dev_flush_recheck_work);
> }
>
> + ufshcd_clear_ua_wluns(hba);
> +
> /* Schedule clock gating in case of no access to UFS device yet */
> ufshcd_release(hba);
>
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] scsi: ufs: fix livelock on ufshcd_clear_ua_wlun
2020-12-17 1:27 ` Stanley Chu
@ 2020-12-17 1:41 ` Jaegeuk Kim
0 siblings, 0 replies; 3+ messages in thread
From: Jaegeuk Kim @ 2020-12-17 1:41 UTC (permalink / raw)
To: Stanley Chu
Cc: linux-kernel, linux-scsi, kernel-team, cang, alim.akhtar,
avri.altman, bvanassche, martin.petersen
On 12/17, Stanley Chu wrote:
> Hi Jaegeuk,
>
> On Wed, 2020-12-16 at 11:02 -0800, Jaegeuk Kim wrote:
> > From: Jaegeuk Kim <jaegeuk@google.com>
> >
> > This fixes the below livelock which is caused by calling a scsi command before
> > ufshcd_scsi_unblock_requests() in ufshcd_ungate_work().
> >
> > Workqueue: ufs_clk_gating_0 ufshcd_ungate_work
> > Call trace:
> > __switch_to+0x298/0x2bc
> > __schedule+0x59c/0x760
> > schedule+0xac/0xf0
> > schedule_timeout+0x44/0x1b4
> > io_schedule_timeout+0x44/0x68
> > wait_for_common_io+0x7c/0x100
> > wait_for_completion_io+0x14/0x20
> > blk_execute_rq+0x94/0xd0
> > __scsi_execute+0x100/0x1c0
> > ufshcd_clear_ua_wlun+0x124/0x1c8
> > ufshcd_host_reset_and_restore+0x1d0/0x2cc
> > ufshcd_link_recovery+0xac/0x134
> > ufshcd_uic_hibern8_exit+0x1e8/0x1f0
> > ufshcd_ungate_work+0xac/0x130
>
> According to the latest mainstream kernel, once
> ufshcd_uic_hibern8_exit() encounters error, instead, error handler work
> will be scheduled without blocking ufshcd_uic_hibern8_exit(). In
> addition, ufshcd_scsi_unblock_requests() would be invoked before leaving
> ufshcd_uic_hibern8_exit(). So this stack is no longer existed.
Oh, thank you for pointing this out. It seems the below patch made it.
4db7a2360597 ("scsi: ufs: Fix concurrency of error handler and other error recovery paths")
Next time, I need to check upstream more carefully. :P
>
> Thanks,
> Stanley Chu
>
> > process_one_work+0x270/0x47c
> > worker_thread+0x27c/0x4d8
> > kthread+0x13c/0x320
> > ret_from_fork+0x10/0x18
> >
> > Fixes: 1918651f2d7e ("scsi: ufs: Clear UAC for RPMB after ufshcd resets")
> > Signed-off-by: Jaegeuk Kim <jaegeuk@google.com>
> > ---
> > drivers/scsi/ufs/ufshcd.c | 6 +++++-
> > 1 file changed, 5 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> > index e221add25a7e..b0998db1b781 100644
> > --- a/drivers/scsi/ufs/ufshcd.c
> > +++ b/drivers/scsi/ufs/ufshcd.c
> > @@ -1603,6 +1603,7 @@ static void ufshcd_ungate_work(struct work_struct *work)
> > }
> > unblock_reqs:
> > ufshcd_scsi_unblock_requests(hba);
> > + ufshcd_clear_ua_wluns(hba);
> > }
> >
> > /**
> > @@ -6913,7 +6914,7 @@ static int ufshcd_host_reset_and_restore(struct ufs_hba *hba)
> >
> > /* Establish the link again and restore the device */
> > err = ufshcd_probe_hba(hba, false);
> > - if (!err)
> > + if (!err && !hba->clk_gating.is_suspended)
> > ufshcd_clear_ua_wluns(hba);
> > out:
> > if (err)
> > @@ -8745,6 +8746,7 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
> > ufshcd_resume_clkscaling(hba);
> > hba->clk_gating.is_suspended = false;
> > hba->dev_info.b_rpm_dev_flush_capable = false;
> > + ufshcd_clear_ua_wluns(hba);
> > ufshcd_release(hba);
> > out:
> > if (hba->dev_info.b_rpm_dev_flush_capable) {
> > @@ -8855,6 +8857,8 @@ static int ufshcd_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)
> > cancel_delayed_work(&hba->rpm_dev_flush_recheck_work);
> > }
> >
> > + ufshcd_clear_ua_wluns(hba);
> > +
> > /* Schedule clock gating in case of no access to UFS device yet */
> > ufshcd_release(hba);
> >
>
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2020-12-17 1:42 UTC | newest]
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2020-12-16 19:02 [PATCH] scsi: ufs: fix livelock on ufshcd_clear_ua_wlun Jaegeuk Kim
2020-12-17 1:27 ` Stanley Chu
2020-12-17 1:41 ` Jaegeuk Kim
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