| Message ID | 20220521073749.3146892-5-yukuai3@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | nbd: bugfix and cleanup patches | expand |
On Sat, May 21, 2022 at 03:37:47PM +0800, Yu Kuai wrote: > In our tests, "qemu-nbd" triggers a io hung: > > INFO: task qemu-nbd:11445 blocked for more than 368 seconds. > Not tainted 5.18.0-rc3-next-20220422-00003-g2176915513ca #884 > "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > task:qemu-nbd state:D stack: 0 pid:11445 ppid: 1 flags:0x00000000 > Call Trace: > <TASK> > __schedule+0x480/0x1050 > ? _raw_spin_lock_irqsave+0x3e/0xb0 > schedule+0x9c/0x1b0 > blk_mq_freeze_queue_wait+0x9d/0xf0 > ? ipi_rseq+0x70/0x70 > blk_mq_freeze_queue+0x2b/0x40 > nbd_add_socket+0x6b/0x270 [nbd] > nbd_ioctl+0x383/0x510 [nbd] > blkdev_ioctl+0x18e/0x3e0 > __x64_sys_ioctl+0xac/0x120 > do_syscall_64+0x35/0x80 > entry_SYSCALL_64_after_hwframe+0x44/0xae > RIP: 0033:0x7fd8ff706577 > RSP: 002b:00007fd8fcdfebf8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 > RAX: ffffffffffffffda RBX: 0000000040000000 RCX: 00007fd8ff706577 > RDX: 000000000000000d RSI: 000000000000ab00 RDI: 000000000000000f > RBP: 000000000000000f R08: 000000000000fbe8 R09: 000055fe497c62b0 > R10: 00000002aff20000 R11: 0000000000000246 R12: 000000000000006d > R13: 0000000000000000 R14: 00007ffe82dc5e70 R15: 00007fd8fcdff9c0 > > "qemu-ndb -d" will call ioctl 'NBD_DISCONNECT' first, however, following > message was found: > > block nbd0: Send disconnect failed -32 > > Which indicate that something is wrong with the server. Then, > "qemu-nbd -d" will call ioctl 'NBD_CLEAR_SOCK', however ioctl can't clear > requests after commit 2516ab1543fd("nbd: only clear the queue on device > teardown"). And in the meantime, request can't complete through timeout > because nbd_xmit_timeout() will always return 'BLK_EH_RESET_TIMER', which > means such request will never be completed in this situation. > > Now that the flag 'NBD_CMD_INFLIGHT' can make sure requests won't > complete multiple times, switch back to call nbd_clear_sock() in > nbd_clear_sock_ioctl(), so that inflight requests can be cleared. > > Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Thanks, Josef
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index a0d0910dae2a..ec736cc52134 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -1429,7 +1429,7 @@ static int nbd_start_device_ioctl(struct nbd_device *nbd) static void nbd_clear_sock_ioctl(struct nbd_device *nbd, struct block_device *bdev) { - sock_shutdown(nbd); + nbd_clear_sock(nbd); __invalidate_device(bdev, true); nbd_bdev_reset(nbd); if (test_and_clear_bit(NBD_RT_HAS_CONFIG_REF,
In our tests, "qemu-nbd" triggers a io hung: INFO: task qemu-nbd:11445 blocked for more than 368 seconds. Not tainted 5.18.0-rc3-next-20220422-00003-g2176915513ca #884 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:qemu-nbd state:D stack: 0 pid:11445 ppid: 1 flags:0x00000000 Call Trace: <TASK> __schedule+0x480/0x1050 ? _raw_spin_lock_irqsave+0x3e/0xb0 schedule+0x9c/0x1b0 blk_mq_freeze_queue_wait+0x9d/0xf0 ? ipi_rseq+0x70/0x70 blk_mq_freeze_queue+0x2b/0x40 nbd_add_socket+0x6b/0x270 [nbd] nbd_ioctl+0x383/0x510 [nbd] blkdev_ioctl+0x18e/0x3e0 __x64_sys_ioctl+0xac/0x120 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7fd8ff706577 RSP: 002b:00007fd8fcdfebf8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000040000000 RCX: 00007fd8ff706577 RDX: 000000000000000d RSI: 000000000000ab00 RDI: 000000000000000f RBP: 000000000000000f R08: 000000000000fbe8 R09: 000055fe497c62b0 R10: 00000002aff20000 R11: 0000000000000246 R12: 000000000000006d R13: 0000000000000000 R14: 00007ffe82dc5e70 R15: 00007fd8fcdff9c0 "qemu-ndb -d" will call ioctl 'NBD_DISCONNECT' first, however, following message was found: block nbd0: Send disconnect failed -32 Which indicate that something is wrong with the server. Then, "qemu-nbd -d" will call ioctl 'NBD_CLEAR_SOCK', however ioctl can't clear requests after commit 2516ab1543fd("nbd: only clear the queue on device teardown"). And in the meantime, request can't complete through timeout because nbd_xmit_timeout() will always return 'BLK_EH_RESET_TIMER', which means such request will never be completed in this situation. Now that the flag 'NBD_CMD_INFLIGHT' can make sure requests won't complete multiple times, switch back to call nbd_clear_sock() in nbd_clear_sock_ioctl(), so that inflight requests can be cleared. Signed-off-by: Yu Kuai <yukuai3@huawei.com> --- drivers/block/nbd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)