From: Bean Huo <beanhuo@micron.com>
Date: Tue, 14 Dec 2021 13:05:37 +0100
Subject: [PATCH] scsi: ufs: core: Fix deadlock issue in
ufshcd_wait_for_doorbell_clr()
Git-commit: 99c66a8868e33522ebc6fd8a99e32f0d544a014f
Patch-mainline: v5.16-rc1
References: jsc#PED-818
Call shost_for_each_device() with holding host->host_lock will cause a
deadlock situation, which will cause the system to stall (the log as
follow). Fix this issue by using __shost_for_each_device() in
ufshcd_pending_cmds().
stalls on CPUs/tasks:
all trace:
__switch_to+0x120/0x170
0xffff800011643998
ask dump for CPU 5:
ask:kworker/u16:2 state:R running task stack: 0 pid: 80 ppid: 2 flags:0x0000000a
orkqueue: events_unbound async_run_entry_fn
all trace:
__switch_to+0x120/0x170
0x0
ask dump for CPU 6:
ask:kworker/u16:6 state:R running task stack: 0 pid: 164 ppid: 2 flags:0x0000000a
orkqueue: events_unbound async_run_entry_fn
all trace:
__switch_to+0x120/0x170
0xffff54e7c4429f80
ask dump for CPU 7:
ask:kworker/u16:4 state:R running task stack: 0 pid: 153 ppid: 2 flags:0x0000000a
orkqueue: events_unbound async_run_entry_fn
all trace:
__switch_to+0x120/0x170
blk_mq_run_hw_queue+0x34/0x110
blk_mq_sched_insert_request+0xb0/0x120
blk_execute_rq_nowait+0x68/0x88
blk_execute_rq+0x4c/0xd8
__scsi_execute+0xec/0x1d0
scsi_vpd_inquiry+0x84/0xf0
scsi_get_vpd_buf+0x34/0xb8
scsi_attach_vpd+0x34/0x140
scsi_probe_and_add_lun+0xa6c/0xab8
__scsi_scan_target+0x438/0x4f8
scsi_scan_channel+0x6c/0xa8
scsi_scan_host_selected+0xf0/0x150
do_scsi_scan_host+0x88/0x90
scsi_scan_host+0x1b4/0x1d0
ufshcd_async_scan+0x248/0x310
async_run_entry_fn+0x30/0x178
process_one_work+0x1e8/0x368
worker_thread+0x40/0x478
kthread+0x174/0x180
ret_from_fork+0x10/0x20
Link: https://lore.kernel.org/r/20211214120537.531628-1-huobean@gmail.com
Fixes: 8d077ede48c1 ("scsi: ufs: Optimize the command queueing code")
Reported-by: YongQin Liu <yongqin.liu@linaro.org>
Reported-by: Amit Pundir <amit.pundir@linaro.org>
Tested-by: John Stultz <john.stultz@linaro.org>
Tested-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Co-developed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Bean Huo <beanhuo@micron.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Hannes Reinecke <hare@suse.com>
---
drivers/scsi/ufs/ufshcd.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 47968f8d8fc4..1049e41abd5b 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -1082,7 +1082,8 @@ static u32 ufshcd_pending_cmds(struct ufs_hba *hba)
struct scsi_device *sdev;
u32 pending = 0;
- shost_for_each_device(sdev, hba->host)
+ lockdep_assert_held(hba->host->host_lock);
+ __shost_for_each_device(sdev, hba->host)
pending += sbitmap_weight(&sdev->budget_map);
return pending;
--
2.35.3