Re: [PATCH] block: I/O error occurs during SATA disk stress test

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 8/24/22 04:36, Gu Mi wrote:
The problem occurs in two async processes, One is when a new IO
calls the blk_mq_start_request() interface to start sending,The other
is that the block layer timer process calls the blk_mq_req_expired
interface to check whether there is an IO timeout.

When an instruction out of sequence occurs between blk_add_timer
and WRITE_ONCE(rq->state,MQ_RQ_IN_FLIGHT) in the interface
blk_mq_start_request,at this time, the block timer is checking the
new IO timeout, Since the req status has been set to MQ_RQ_IN_FLIGHT
and req->deadline is 0 at this time, the new IO will be misjudged as
a timeout.

Our repair plan is for the deadline to be 0, and we do not think
that a timeout occurs. At the same time, because the jiffies of the
32-bit system will be reversed shortly after the system is turned on,
we will add 1 jiffies to the deadline at this time.

Signed-off-by: Gu Mi <gumi@xxxxxxxxxxxxxxxxx>
---
  block/blk-mq.c      | 2 ++
  block/blk-timeout.c | 4 ++++
  2 files changed, 6 insertions(+)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 4b90d2d..6defaa1 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1451,6 +1451,8 @@ static bool blk_mq_req_expired(struct request *rq, unsigned long *next)
  		return false;
deadline = READ_ONCE(rq->deadline);
+	if (unlikely(deadline == 0))
+		return false;
  	if (time_after_eq(jiffies, deadline))
  		return true;
diff --git a/block/blk-timeout.c b/block/blk-timeout.c
index 1b8de041..6fc5088 100644
--- a/block/blk-timeout.c
+++ b/block/blk-timeout.c
@@ -140,6 +140,10 @@ void blk_add_timer(struct request *req)
  	req->rq_flags &= ~RQF_TIMED_OUT;
expiry = jiffies + req->timeout;
+#ifndef CONFIG_64BIT
+/* In case INITIAL_JIFFIES wraps on 32-bit */
+	expiry |= 1UL;
+#endif
  	WRITE_ONCE(req->deadline, expiry);
/*

Shouldn't this be fixed by inserting a barrier inside blk_mq_start_request() instead of a patch like the above?

Thanks,

Bart.



[Index of Archives]     [Linux RAID]     [Linux SCSI]     [Linux ATA RAID]     [IDE]     [Linux Wireless]     [Linux Kernel]     [ATH6KL]     [Linux Bluetooth]     [Linux Netdev]     [Kernel Newbies]     [Security]     [Git]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Device Mapper]

  Powered by Linux