On 10/21/24 2:43 AM, Peter Wang (王信友) wrote:
Using blk_mq_quiesce_tagset instead of ufshcd_scsi_block_requests
could cause issues. After the patch below was merged, Mediatek
received three cases of IO hang.
77691af484e2 ("scsi: ufs: core: Quiesce request queues before checking
pending cmds")
I think this patch might need to be reverted first.
Here is backtrace of IO hang.
ppid=3952 pid=3952 D cpu=6 prio=120 wait=188s kworker/u16:0
vmlinux __synchronize_srcu() + 216
</proc/self/cwd/common/kernel/rcu/srcutree.c:1386>
vmlinux synchronize_srcu() + 276
</proc/self/cwd/common/kernel/rcu/srcutree.c:0>
vmlinux blk_mq_wait_quiesce_done() + 20
</proc/self/cwd/common/block/blk-mq.c:226>
vmlinux blk_mq_quiesce_tagset() + 156
</proc/self/cwd/common/block/blk-mq.c:286>
vmlinux ufshcd_clock_scaling_prepare(timeout_us=1000000) + 16
</proc/self/cwd/common/drivers/ufs/core/ufshcd.c:1276>
vmlinux ufshcd_devfreq_scale() + 52
</proc/self/cwd/common/drivers/ufs/core/ufshcd.c:1322>
vmlinux ufshcd_devfreq_target() + 384
</proc/self/cwd/common/drivers/ufs/core/ufshcd.c:1440>
vmlinux devfreq_set_target(flags=0) + 184
</proc/self/cwd/common/drivers/devfreq/devfreq.c:363>
vmlinux devfreq_update_target(freq=0) + 296
</proc/self/cwd/common/drivers/devfreq/devfreq.c:429>
vmlinux update_devfreq() + 8
</proc/self/cwd/common/drivers/devfreq/devfreq.c:444>
vmlinux devfreq_monitor() + 48
</proc/self/cwd/common/drivers/devfreq/devfreq.c:460>
vmlinux process_one_work() + 476
</proc/self/cwd/common/kernel/workqueue.c:2643>
vmlinux process_scheduled_works() + 580
</proc/self/cwd/common/kernel/workqueue.c:2717>
vmlinux worker_thread() + 576
</proc/self/cwd/common/kernel/workqueue.c:2798>
vmlinux kthread() + 272
</proc/self/cwd/common/kernel/kthread.c:388>
vmlinux 0xFFFFFFE239A164EC()
</proc/self/cwd/common/arch/arm64/kernel/entry.S:846>
Hi Peter,
Thank you very much for having reported this hang early. Would it be
possible for you to test the patch below on top of this patch series?
I think the root cause of the hang that you reported is in the block
layer.
Thanks,
Bart.
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 7b02188feed5..7482e682deca 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -283,8 +283,9 @@ void blk_mq_quiesce_tagset(struct blk_mq_tag_set *set)
if (!blk_queue_skip_tagset_quiesce(q))
blk_mq_quiesce_queue_nowait(q);
}
- blk_mq_wait_quiesce_done(set);
mutex_unlock(&set->tag_list_lock);
+
+ blk_mq_wait_quiesce_done(set);
}
EXPORT_SYMBOL_GPL(blk_mq_quiesce_tagset);
