On Mon, Nov 30, 2020 at 11:22:33AM +0000, John Garry wrote: > Hi all, > > Some guys internally upgraded to v5.10-rcX and start to see a hang after dd > + sync for a large file: > - mount /dev/sda1 (ext4 filesystem) to directory /mnt; > - run "if=/dev/zero of=test1 bs=1M count=2000" on directory /mnt; > - run "sync" > > and get: > > [ 367.912761] INFO: task jbd2/sdb1-8:3602 blocked for more than 120 > seconds. > [ 367.919618] Not tainted 5.10.0-rc1-109488-g32ded76956b6 #948 > [ 367.925776] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" > disables this message. > [ 367.933579] task:jbd2/sdb1-8 state:D stack: 0 pid: 3602 > ppid: 2 flags:0x00000028 > [ 367.941901] Call trace: > [ 367.944351] __switch_to+0xb8/0x168 > [ 367.947840] __schedule+0x30c/0x670 > [ 367.951326] schedule+0x70/0x108 > [ 367.954550] io_schedule+0x1c/0xe8 > [ 367.957948] bit_wait_io+0x18/0x68 > [ 367.961346] __wait_on_bit+0x78/0xf0 > [ 367.964919] out_of_line_wait_on_bit+0x8c/0xb0 > [ 367.969356] __wait_on_buffer+0x30/0x40 > [ 367.973188] jbd2_journal_commit_transaction+0x1370/0x1958 > [ 367.978661] kjournald2+0xcc/0x260 > [ 367.982061] kthread+0x150/0x158 > [ 367.985288] ret_from_fork+0x10/0x34 > [ 367.988860] INFO: task sync:3823 blocked for more than 120 seconds. > [ 367.995102] Not tainted 5.10.0-rc1-109488-g32ded76956b6 #948 > [ 368.001265] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" > disables this message. > [ 368.009067] task:sync state:D stack: 0 pid: 3823 ppid: > 3450 flags:0x00000009 > [ 368.017397] Call trace: > [ 368.019841] __switch_to+0xb8/0x168 > [ 368.023320] __schedule+0x30c/0x670 > [ 368.026804] schedule+0x70/0x108 > [ 368.030025] jbd2_log_wait_commit+0xbc/0x158 > [ 368.034290] ext4_sync_fs+0x188/0x1c8 > [ 368.037947] sync_fs_one_sb+0x30/0x40 > [ 368.041606] iterate_supers+0x9c/0x138 > [ 368.045350] ksys_sync+0x64/0xc0 > [ 368.048569] __arm64_sys_sync+0x10/0x20 > [ 368.052398] el0_svc_common.constprop.3+0x68/0x170 > [ 368.057177] do_el0_svc+0x24/0x90 > [ 368.060482] el0_sync_handler+0x118/0x168 > [ 368.064478] el0_sync+0x158/0x180 > > The issue was reported here originally: > https://lore.kernel.org/linux-ext4/4d18326e-9ca2-d0cb-7cb8-cb56981280da@xxxxxxxxxxxxx/ > > But it looks like issue related to recent work for SCSI MQ. > > They can only create with hisi_sas v3 hw. I could not create with megaraid > sas on the same dev platform or hisi_sas on a similar dev board. > > Reverting "scsi: core: Only re-run queue in scsi_end_request() if device > queue is busy" seems solve the issue. Also, checking out to patch prior to > "scsi: hisi_sas: Switch v3 hw to MQ" seems to not have the issue. If the issue can be reproduced, you may try the following patch: diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 60c7a7d74852..f95bd0e5006e 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -602,6 +602,9 @@ static bool scsi_end_request(struct request *req, blk_status_t error, __blk_mq_end_request(req, error); + if (unlikely(req->end_io)) + smp_mb(); + scsi_run_queue_async(sdev); percpu_ref_put(&q->q_usage_counter); Thanks, Ming
