Suwan Kim 37fafe6b61 virtio-blk: Fix WARN_ON_ONCE in virtio_queue_rq()
If a request fails at virtio_queue_rqs(), it is inserted to requeue_list
and passed to virtio_queue_rq(). Then blk_mq_start_request() can be called
again at virtio_queue_rq() and trigger WARN_ON_ONCE like below trace because
request state was already set to MQ_RQ_IN_FLIGHT in virtio_queue_rqs()
despite the failure.

[    1.890468] ------------[ cut here ]------------
[    1.890776] WARNING: CPU: 2 PID: 122 at block/blk-mq.c:1143
blk_mq_start_request+0x8a/0xe0
[    1.891045] Modules linked in:
[    1.891250] CPU: 2 PID: 122 Comm: journal-offline Not tainted 5.19.0+ #44
[    1.891504] Hardware name: ChromiumOS crosvm, BIOS 0
[    1.891739] RIP: 0010:blk_mq_start_request+0x8a/0xe0
[    1.891961] Code: 12 80 74 22 48 8b 4b 10 8b 89 64 01 00 00 8b 53
20 83 fa ff 75 08 ba 00 00 00 80 0b 53 24 c1 e1 10 09 d1 89 48 34 5b
41 5e c3 <0f> 0b eb b8 65 8b 05 2b 39 b6 7e 89 c0 48 0f a3 05 39 77 5b
01 0f
[    1.892443] RSP: 0018:ffffc900002777b0 EFLAGS: 00010202
[    1.892673] RAX: 0000000000000000 RBX: ffff888004bc0000 RCX: 0000000000000000
[    1.892952] RDX: 0000000000000000 RSI: ffff888003d7c200 RDI: ffff888004bc0000
[    1.893228] RBP: 0000000000000000 R08: 0000000000000001 R09: ffff888004bc0100
[    1.893506] R10: ffffffffffffffff R11: ffffffff8185ca10 R12: ffff888004bc0000
[    1.893797] R13: ffffc90000277900 R14: ffff888004ab2340 R15: ffff888003d86e00
[    1.894060] FS:  00007ffa143a4640(0000) GS:ffff88807dd00000(0000)
knlGS:0000000000000000
[    1.894412] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[    1.894682] CR2: 00005648577d9088 CR3: 00000000053da004 CR4: 0000000000170ee0
[    1.894953] Call Trace:
[    1.895139]  <TASK>
[    1.895303]  virtblk_prep_rq+0x1e5/0x280
[    1.895509]  virtio_queue_rq+0x5c/0x310
[    1.895710]  ? virtqueue_add_sgs+0x95/0xb0
[    1.895905]  ? _raw_spin_unlock_irqrestore+0x16/0x30
[    1.896133]  ? virtio_queue_rqs+0x340/0x390
[    1.896453]  ? sbitmap_get+0xfa/0x220
[    1.896678]  __blk_mq_issue_directly+0x41/0x180
[    1.896906]  blk_mq_plug_issue_direct+0xd8/0x2c0
[    1.897115]  blk_mq_flush_plug_list+0x115/0x180
[    1.897342]  blk_add_rq_to_plug+0x51/0x130
[    1.897543]  blk_mq_submit_bio+0x3a1/0x570
[    1.897750]  submit_bio_noacct_nocheck+0x418/0x520
[    1.897985]  ? submit_bio_noacct+0x1e/0x260
[    1.897989]  ext4_bio_write_page+0x222/0x420
[    1.898000]  mpage_process_page_bufs+0x178/0x1c0
[    1.899451]  mpage_prepare_extent_to_map+0x2d2/0x440
[    1.899603]  ext4_writepages+0x495/0x1020
[    1.899733]  do_writepages+0xcb/0x220
[    1.899871]  ? __seccomp_filter+0x171/0x7e0
[    1.900006]  file_write_and_wait_range+0xcd/0xf0
[    1.900167]  ext4_sync_file+0x72/0x320
[    1.900308]  __x64_sys_fsync+0x66/0xa0
[    1.900449]  do_syscall_64+0x31/0x50
[    1.900595]  entry_SYSCALL_64_after_hwframe+0x63/0xcd
[    1.900747] RIP: 0033:0x7ffa16ec96ea
[    1.900883] Code: b8 4a 00 00 00 0f 05 48 3d 00 f0 ff ff 77 41 c3
48 83 ec 18 89 7c 24 0c e8 e3 02 f8 ff 8b 7c 24 0c 89 c2 b8 4a 00 00
00 0f 05 <48> 3d 00 f0 ff ff 77 36 89 d7 89 44 24 0c e8 43 03 f8 ff 8b
44 24
[    1.901302] RSP: 002b:00007ffa143a3ac0 EFLAGS: 00000293 ORIG_RAX:
000000000000004a
[    1.901499] RAX: ffffffffffffffda RBX: 0000560277ec6fe0 RCX: 00007ffa16ec96ea
[    1.901696] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000016
[    1.901884] RBP: 0000560277ec5910 R08: 0000000000000000 R09: 00007ffa143a4640
[    1.902082] R10: 00007ffa16e4d39e R11: 0000000000000293 R12: 00005602773f59e0
[    1.902459] R13: 0000000000000000 R14: 00007fffbfc007ff R15: 00007ffa13ba4000
[    1.902763]  </TASK>
[    1.902877] ---[ end trace 0000000000000000 ]---

To avoid calling blk_mq_start_request() twice, This patch moves the
execution of blk_mq_start_request() to the end of virtblk_prep_rq().
And instead of requeuing failed request to plug list in the error path of
virtblk_add_req_batch(), it uses blk_mq_requeue_request() to change failed
request state to MQ_RQ_IDLE. Then virtblk can safely handle the request
on the next trial.

Fixes: 0e9911fa76 ("virtio-blk: support mq_ops->queue_rqs()")
Reported-by: Alexandre Courbot <acourbot@chromium.org>
Tested-by: Alexandre Courbot <acourbot@chromium.org>
Signed-off-by: Suwan Kim <suwan.kim027@gmail.com>
Message-Id: <20220830150153.12627-1-suwan.kim027@gmail.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Pankaj Raghav <p.raghav@samsung.com>
2022-09-27 18:30:49 -04:00
2022-09-27 18:30:49 -04:00
2022-09-25 14:01:02 -07:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
Description
No description provided
Readme 7.9 GiB
Languages
C 97.7%
Assembly 1.6%
Makefile 0.3%
Perl 0.1%