From: syzbot <syzbot+643e4ce4b6ad1347d372@syzkaller.appspotmail.com>
To: axboe@kernel.dk, linux-block@vger.kernel.org,
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] possible deadlock in blkdev_put (2)
Date: Tue, 07 Dec 2021 21:05:17 -0800 [thread overview]
Message-ID: <0000000000009debe105d29b6fb4@google.com> (raw)
In-Reply-To: <0000000000007f2f5405d1bfe618@google.com>
syzbot has found a reproducer for the following issue on:
HEAD commit: 04fe99a8d936 Add linux-next specific files for 20211207
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1315e2b9b00000
kernel config: https://syzkaller.appspot.com/x/.config?x=4589399873466942
dashboard link: https://syzkaller.appspot.com/bug?extid=643e4ce4b6ad1347d372
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11bb96ceb00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15ad1badb00000
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+643e4ce4b6ad1347d372@syzkaller.appspotmail.com
======================================================
WARNING: possible circular locking dependency detected
5.16.0-rc4-next-20211207-syzkaller #0 Not tainted
------------------------------------------------------
systemd-udevd/7081 is trying to acquire lock:
ffff88802358c938 ((wq_completion)loop3){+.+.}-{0:0}, at: flush_workqueue+0xe1/0x15b0 kernel/workqueue.c:2835
but task is already holding lock:
ffff88801a57a118 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0x99/0x980 block/bdev.c:907
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #6 (&disk->open_mutex){+.+.}-{3:3}:
__mutex_lock_common kernel/locking/mutex.c:607 [inline]
__mutex_lock+0x12f/0x12f0 kernel/locking/mutex.c:740
blkdev_get_by_dev.part.0+0x40e/0xc70 block/bdev.c:809
blkdev_get_by_dev+0x6b/0x80 block/bdev.c:852
swsusp_check+0x97/0x2f0 kernel/power/swap.c:1520
software_resume.part.0+0x102/0x1f0 kernel/power/hibernate.c:979
software_resume kernel/power/hibernate.c:86 [inline]
resume_store+0x161/0x190 kernel/power/hibernate.c:1181
kobj_attr_store+0x50/0x80 lib/kobject.c:856
sysfs_kf_write+0x110/0x160 fs/sysfs/file.c:136
kernfs_fop_write_iter+0x342/0x500 fs/kernfs/file.c:296
call_write_iter include/linux/fs.h:2079 [inline]
new_sync_write+0x429/0x660 fs/read_write.c:503
vfs_write+0x7cd/0xae0 fs/read_write.c:590
ksys_write+0x12d/0x250 fs/read_write.c:643
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
-> #5 (system_transition_mutex/1){+.+.}-{3:3}:
__mutex_lock_common kernel/locking/mutex.c:607 [inline]
__mutex_lock+0x12f/0x12f0 kernel/locking/mutex.c:740
software_resume.part.0+0x19/0x1f0 kernel/power/hibernate.c:934
software_resume kernel/power/hibernate.c:86 [inline]
resume_store+0x161/0x190 kernel/power/hibernate.c:1181
kobj_attr_store+0x50/0x80 lib/kobject.c:856
sysfs_kf_write+0x110/0x160 fs/sysfs/file.c:136
kernfs_fop_write_iter+0x342/0x500 fs/kernfs/file.c:296
call_write_iter include/linux/fs.h:2079 [inline]
new_sync_write+0x429/0x660 fs/read_write.c:503
vfs_write+0x7cd/0xae0 fs/read_write.c:590
ksys_write+0x12d/0x250 fs/read_write.c:643
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
-> #4 (&of->mutex){+.+.}-{3:3}:
__mutex_lock_common kernel/locking/mutex.c:607 [inline]
__mutex_lock+0x12f/0x12f0 kernel/locking/mutex.c:740
kernfs_seq_start+0x4b/0x260 fs/kernfs/file.c:112
seq_read_iter+0x2c7/0x1240 fs/seq_file.c:225
kernfs_fop_read_iter+0x44f/0x5f0 fs/kernfs/file.c:241
call_read_iter include/linux/fs.h:2073 [inline]
new_sync_read+0x421/0x6e0 fs/read_write.c:400
vfs_read+0x35c/0x600 fs/read_write.c:481
ksys_read+0x12d/0x250 fs/read_write.c:619
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
-> #3 (&p->lock){+.+.}-{3:3}:
__mutex_lock_common kernel/locking/mutex.c:607 [inline]
__mutex_lock+0x12f/0x12f0 kernel/locking/mutex.c:740
seq_read_iter+0xdf/0x1240 fs/seq_file.c:182
call_read_iter include/linux/fs.h:2073 [inline]
generic_file_splice_read+0x453/0x6d0 fs/splice.c:311
do_splice_to+0x1bf/0x250 fs/splice.c:796
splice_direct_to_actor+0x2c2/0x8c0 fs/splice.c:870
do_splice_direct+0x1b3/0x280 fs/splice.c:979
do_sendfile+0xaf2/0x1250 fs/read_write.c:1245
__do_sys_sendfile64 fs/read_write.c:1310 [inline]
__se_sys_sendfile64 fs/read_write.c:1296 [inline]
__x64_sys_sendfile64+0x1cc/0x210 fs/read_write.c:1296
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
-> #2 (sb_writers#3){.+.+}-{0:0}:
percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
__sb_start_write include/linux/fs.h:1727 [inline]
sb_start_write include/linux/fs.h:1797 [inline]
file_start_write include/linux/fs.h:2942 [inline]
lo_write_bvec drivers/block/loop.c:242 [inline]
lo_write_simple drivers/block/loop.c:265 [inline]
do_req_filebacked drivers/block/loop.c:494 [inline]
loop_handle_cmd drivers/block/loop.c:1846 [inline]
loop_process_work+0x1499/0x1db0 drivers/block/loop.c:1886
process_one_work+0x9b2/0x1690 kernel/workqueue.c:2318
worker_thread+0x658/0x11f0 kernel/workqueue.c:2465
kthread+0x405/0x4f0 kernel/kthread.c:345
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
-> #1 ((work_completion)(&lo->rootcg_work)){+.+.}-{0:0}:
process_one_work+0x921/0x1690 kernel/workqueue.c:2294
worker_thread+0x658/0x11f0 kernel/workqueue.c:2465
kthread+0x405/0x4f0 kernel/kthread.c:345
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
-> #0 ((wq_completion)loop3){+.+.}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3063 [inline]
check_prevs_add kernel/locking/lockdep.c:3186 [inline]
validate_chain kernel/locking/lockdep.c:3801 [inline]
__lock_acquire+0x2a07/0x54a0 kernel/locking/lockdep.c:5027
lock_acquire kernel/locking/lockdep.c:5637 [inline]
lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5602
flush_workqueue+0x110/0x15b0 kernel/workqueue.c:2838
drain_workqueue+0x1a5/0x3c0 kernel/workqueue.c:3003
destroy_workqueue+0x71/0x800 kernel/workqueue.c:4440
__loop_clr_fd+0x1ab/0xe20 drivers/block/loop.c:1118
lo_release+0x1ac/0x1f0 drivers/block/loop.c:1750
blkdev_put_whole block/bdev.c:694 [inline]
blkdev_put+0x2de/0x980 block/bdev.c:949
blkdev_close+0x6a/0x80 block/fops.c:516
__fput+0x286/0x9f0 fs/file_table.c:311
task_work_run+0xdd/0x1a0 kernel/task_work.c:164
tracehook_notify_resume include/linux/tracehook.h:189 [inline]
exit_to_user_mode_loop kernel/entry/common.c:175 [inline]
exit_to_user_mode_prepare+0x27e/0x290 kernel/entry/common.c:207
__syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:300
do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x44/0xae
other info that might help us debug this:
Chain exists of:
(wq_completion)loop3 --> system_transition_mutex/1 --> &disk->open_mutex
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&disk->open_mutex);
lock(system_transition_mutex/1);
lock(&disk->open_mutex);
lock((wq_completion)loop3);
*** DEADLOCK ***
1 lock held by systemd-udevd/7081:
#0: ffff88801a57a118 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0x99/0x980 block/bdev.c:907
stack backtrace:
CPU: 1 PID: 7081 Comm: systemd-udevd Not tainted 5.16.0-rc4-next-20211207-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
check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2143
check_prev_add kernel/locking/lockdep.c:3063 [inline]
check_prevs_add kernel/locking/lockdep.c:3186 [inline]
validate_chain kernel/locking/lockdep.c:3801 [inline]
__lock_acquire+0x2a07/0x54a0 kernel/locking/lockdep.c:5027
lock_acquire kernel/locking/lockdep.c:5637 [inline]
lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5602
flush_workqueue+0x110/0x15b0 kernel/workqueue.c:2838
drain_workqueue+0x1a5/0x3c0 kernel/workqueue.c:3003
destroy_workqueue+0x71/0x800 kernel/workqueue.c:4440
__loop_clr_fd+0x1ab/0xe20 drivers/block/loop.c:1118
lo_release+0x1ac/0x1f0 drivers/block/loop.c:1750
blkdev_put_whole block/bdev.c:694 [inline]
blkdev_put+0x2de/0x980 block/bdev.c:949
blkdev_close+0x6a/0x80 block/fops.c:516
__fput+0x286/0x9f0 fs/file_table.c:311
task_work_run+0xdd/0x1a0 kernel/task_work.c:164
tracehook_notify_resume include/linux/tracehook.h:189 [inline]
exit_to_user_mode_loop kernel/entry/common.c:175 [inline]
exit_to_user_mode_prepare+0x27e/0x290 kernel/entry/common.c:207
__syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:300
do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f5387c2b270
Code: 73 01 c3 48 8b 0d 38 7d 20 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 83 3d 59 c1 20 00 00 75 10 b8 03 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 ee fb ff ff 48 89 04 24
RSP: 002b:00007ffce06abcb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000007 RCX: 00007f5387c2b270
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000007
RBP: 00007f5388ae5710 R08: 00005621f86a7af0 R09: 00005621f86b5700
R10: 00007f5388ae58c0 R11: 0000000000000246 R12: 0000000000000000
R13: 00005621f86a3e40 R14: 0000000000000003 R15: 000000000000000e
</TASK>
I/O error, dev loop2, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0
I/O error, dev loop2, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0
I/O error, dev loop2, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
Buffer I/O error on dev loop2, logical block 0, async page read
I/O error, dev loop3, sector 1 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
Buffer I/O error on dev loop3, logical block 1, async page read
I/O error, dev loop3, sector 1 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
Buffer I/O error on dev loop3, logical block 1, async page read
next prev parent reply other threads:[~2021-12-08 5:05 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-27 7:10 [syzbot] possible deadlock in blkdev_put (2) syzbot
2021-12-08 5:05 ` syzbot [this message]
2021-12-08 11:42 ` syzbot
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