[syzbot] INFO: task hung in lo_release (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 4c388a8e740d Merge tag 'zstd-for-linus-5.16-rc1' of git://..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=143d2c06b00000
kernel config: https://syzkaller.appspot.com/x/.config?x=b7264d1cb8ba2795
dashboard link: https://syzkaller.appspot.com/bug?extid=5e403cab907a802d6a9f
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5e403c...@syzkaller.appspotmail.com

INFO: task syz-executor.3:14593 blocked for more than 143 seconds.
Not tainted 5.16.0-rc1-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.3 state:D stack:26472 pid:14593 ppid: 8449 flags:0x00004004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:4972 [inline]
__schedule+0xa9a/0x4940 kernel/sched/core.c:6253
schedule+0xd2/0x260 kernel/sched/core.c:6326
blk_mq_freeze_queue_wait+0x112/0x160 block/blk-mq.c:178
lo_release+0x160/0x1f0 drivers/block/loop.c:1768
blkdev_put_whole block/bdev.c:694 [inline]
blkdev_put+0x2fb/0x9e0 block/bdev.c:956
btrfs_close_bdev fs/btrfs/volumes.c:1114 [inline]
btrfs_close_bdev fs/btrfs/volumes.c:1104 [inline]
btrfs_close_one_device fs/btrfs/volumes.c:1135 [inline]
close_fs_devices+0x24f/0xa60 fs/btrfs/volumes.c:1178
btrfs_close_devices+0x8e/0x4b0 fs/btrfs/volumes.c:1193
open_ctree+0x48af/0x4954 fs/btrfs/disk-io.c:3700
btrfs_fill_super fs/btrfs/super.c:1359 [inline]
btrfs_mount_root.cold+0x15/0x162 fs/btrfs/super.c:1726
legacy_get_tree+0x105/0x220 fs/fs_context.c:610
vfs_get_tree+0x89/0x2f0 fs/super.c:1500
fc_mount fs/namespace.c:994 [inline]
vfs_kern_mount.part.0+0xd3/0x170 fs/namespace.c:1024
vfs_kern_mount+0x3c/0x60 fs/namespace.c:1011
btrfs_mount+0x234/0xa60 fs/btrfs/super.c:1786
legacy_get_tree+0x105/0x220 fs/fs_context.c:610
vfs_get_tree+0x89/0x2f0 fs/super.c:1500
do_new_mount fs/namespace.c:2988 [inline]
path_mount+0x1320/0x1fa0 fs/namespace.c:3318
do_mount fs/namespace.c:3331 [inline]
__do_sys_mount fs/namespace.c:3539 [inline]
__se_sys_mount fs/namespace.c:3516 [inline]
__x64_sys_mount+0x27f/0x300 fs/namespace.c:3516
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7fea85df401a
RSP: 002b:00007fea83367fa8 EFLAGS: 00000206 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00000000200009c0 RCX: 00007fea85df401a
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007fea83368000
RBP: 00007fea83368040 R08: 00007fea83368040 R09: 0000000020000000
R10: 0000000000010809 R11: 0000000000000206 R12: 0000000020000000
R13: 0000000020000100 R14: 00007fea83368000 R15: 00000000200005c0
</TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/26:
#0: ffffffff8bb80fe0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6458
1 lock held by in:imklog/6236:
#0: ffff888020fea8f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:990
2 locks held by kworker/u4:12/12192:
#0: ffff8880b9d39b18 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2b/0x120 kernel/sched/core.c:478
#1: ffffc90004a7fdb0 ((work_completion)(&(&bat_priv->nc.work)->work)){+.+.}-{0:0}, at: process_one_work+0x8ca/0x1690 kernel/workqueue.c:2273
4 locks held by syz-executor.3/14593:
#0: ffff88803a2da0e0 (&type->s_umount_key#73/1){+.+.}-{3:3}, at: alloc_super+0x1dd/0xac0 fs/super.c:229
#1: ffffffff8c25fc48 (uuid_mutex){+.+.}-{3:3}, at: btrfs_close_devices+0x86/0x4b0 fs/btrfs/volumes.c:1192
#2: ffff88801ad79118 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0x97/0x9e0 block/bdev.c:914
#3: ffff88801adcab60 (&lo->lo_mutex){+.+.}-{3:3}, at: lo_release+0x4d/0x1f0 drivers/block/loop.c:1748

=============================================

NMI backtrace for cpu 0
CPU: 0 PID: 26 Comm: khungtaskd Not tainted 5.16.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:210 [inline]
watchdog+0xc1d/0xf50 kernel/hung_task.c:295
kthread+0x405/0x4f0 kernel/kthread.c:327
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 2961 Comm: systemd-journal Not tainted 5.16.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:PageTail include/linux/page-flags.h:237 [inline]
RIP: 0010:free_tail_pages_check+0x94/0x2d0 mm/page_alloc.c:1246
Code: b8 01 00 00 00 eb 4a 4c 8d 6e 08 4c 8d 66 18 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 80 3c 02 00 0f 85 fb 01 00 00 <48> 8b 45 08 f7 d0 83 e0 01 0f 85 56 01 00 00 48 8b 4d 08 48 8d 51
RSP: 0018:ffffc90002057c58 EFLAGS: 00000046
RAX: dffffc0000000000 RBX: ffffea00023df100 RCX: ffffffff81b2a420
RDX: 1ffffd400047be29 RSI: 0000000000000004 RDI: ffffea00023df154
RBP: ffffea00023df140 R08: 0000000000000000 R09: ffffea00023df157
R10: fffff9400047be2a R11: 000000000000001f R12: ffffea00023df158
R13: ffffea00023df148 R14: ffffea00023df154 R15: ffffea00023df100
FS: 00007f24420758c0(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f243f5be000 CR3: 00000000776d0000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
free_pages_prepare mm/page_alloc.c:1319 [inline]
free_pcp_prepare+0x560/0x870 mm/page_alloc.c:1389
free_unref_page_prepare mm/page_alloc.c:3309 [inline]
free_unref_page+0x19/0x690 mm/page_alloc.c:3388
slab_destroy mm/slab.c:1627 [inline]
slabs_destroy+0x89/0xc0 mm/slab.c:1647
cache_flusharray mm/slab.c:3418 [inline]
___cache_free+0x4cc/0x610 mm/slab.c:3480
qlink_free mm/kasan/quarantine.c:146 [inline]
qlist_free_all+0x4e/0x110 mm/kasan/quarantine.c:165
kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:272
__kasan_slab_alloc+0x97/0xb0 mm/kasan/common.c:444
kasan_slab_alloc include/linux/kasan.h:259 [inline]
slab_post_alloc_hook mm/slab.h:519 [inline]
slab_alloc mm/slab.c:3323 [inline]
kmem_cache_alloc+0x265/0x560 mm/slab.c:3507
getname_flags.part.0+0x50/0x4f0 fs/namei.c:138
getname_flags include/linux/audit.h:323 [inline]
getname fs/namei.c:217 [inline]
__do_sys_mkdir fs/namei.c:3929 [inline]
__se_sys_mkdir fs/namei.c:3927 [inline]
__x64_sys_mkdir+0xda/0x140 fs/namei.c:3927
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f2441330687
Code: 00 b8 ff ff ff ff c3 0f 1f 40 00 48 8b 05 09 d8 2b 00 64 c7 00 5f 00 00 00 b8 ff ff ff ff c3 0f 1f 40 00 b8 53 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d e1 d7 2b 00 f7 d8 64 89 01 48
RSP: 002b:00007ffecd753e08 EFLAGS: 00000293 ORIG_RAX: 0000000000000053
RAX: ffffffffffffffda RBX: 00007ffecd756e70 RCX: 00007f2441330687
RDX: 0000000000000000 RSI: 00000000000001ed RDI: 0000560cc21068c0
RBP: 00007ffecd753e40 R08: 0000560cc07433e5 R09: 0000000000000018
R10: 0000000000000069 R11: 0000000000000293 R12: 0000000000000000
R13: 0000000000000001 R14: 0000560cc21068c0 R15: 00007ffecd754480
</TASK>
----------------
Code disassembly (best guess):
0: b8 01 00 00 00 mov $0x1,%eax
5: eb 4a jmp 0x51
7: 4c 8d 6e 08 lea 0x8(%rsi),%r13
b: 4c 8d 66 18 lea 0x18(%rsi),%r12
f: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
16: fc ff df
19: 4c 89 ea mov %r13,%rdx
1c: 48 c1 ea 03 shr $0x3,%rdx
20: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1)
24: 0f 85 fb 01 00 00 jne 0x225
* 2a: 48 8b 45 08 mov 0x8(%rbp),%rax <-- trapping instruction
2e: f7 d0 not %eax
30: 83 e0 01 and $0x1,%eax
33: 0f 85 56 01 00 00 jne 0x18f
39: 48 8b 4d 08 mov 0x8(%rbp),%rcx
3d: 48 rex.W
3e: 8d .byte 0x8d
3f: 51 push %rcx


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[syzbot]

> #syz dup: INFO: task can't die in blk_mq_freeze_queue_wait

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