From: syzbot <syzbot+b9e4c31d0a1efb34cb03@syzkaller.appspotmail.com>
To: axboe@kernel.dk, cgroups@vger.kernel.org,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
ming.lei@redhat.com, syzkaller-bugs@googlegroups.com,
tj@kernel.org
Subject: [syzbot] possible deadlock in blkcg_deactivate_policy
Date: Fri, 15 Apr 2022 11:29:33 -0700 [thread overview]
Message-ID: <00000000000092e0d405dcb597d4@google.com> (raw)
Hello,
syzbot found the following issue on:
HEAD commit: b9b4c79e5830 Merge tag 'sound-5.18-rc3' of git://git.kerne..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=118c96ccf00000
kernel config: https://syzkaller.appspot.com/x/.config?x=eb177500e563582f
dashboard link: https://syzkaller.appspot.com/bug?extid=b9e4c31d0a1efb34cb03
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=16ab7a70f00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16e54770f00000
The issue was bisected to:
commit 0a9a25ca78437b39e691bcc3dc8240455b803d8d
Author: Ming Lei <ming.lei@redhat.com>
Date: Fri Mar 18 13:01:43 2022 +0000
block: let blkcg_gq grab request queue's refcnt
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=128129e0f00000
final oops: https://syzkaller.appspot.com/x/report.txt?x=118129e0f00000
console output: https://syzkaller.appspot.com/x/log.txt?x=168129e0f00000
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b9e4c31d0a1efb34cb03@syzkaller.appspotmail.com
Fixes: 0a9a25ca7843 ("block: let blkcg_gq grab request queue's refcnt")
RBP: 00007ffcdacd3400 R08: 0000000000000002 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000004
R13: 431bde82d7b634db R14: 0000000000000000 R15: 0000000000000000
</TASK>
======================================================
WARNING: possible circular locking dependency detected
5.18.0-rc2-syzkaller-00122-gb9b4c79e5830 #0 Not tainted
------------------------------------------------------
syz-executor173/3613 is trying to acquire lock:
ffff8880168900a8 ((&sq->pending_timer)){+.-.}-{0:0}, at: del_timer_sync+0x33/0x1b0 kernel/time/timer.c:1363
but task is already holding lock:
ffffffff9070b710 (&blkcg->lock){....}-{2:2}, at: spin_lock include/linux/spinlock.h:349 [inline]
ffffffff9070b710 (&blkcg->lock){....}-{2:2}, at: blkcg_deactivate_policy block/blk-cgroup.c:1441 [inline]
ffffffff9070b710 (&blkcg->lock){....}-{2:2}, at: blkcg_deactivate_policy+0x1e7/0x4e0 block/blk-cgroup.c:1423
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (&blkcg->lock){....}-{2:2}:
__raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
_raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:349 [inline]
blkg_create+0x47b/0x1030 block/blk-cgroup.c:301
blkcg_init_queue+0xfe/0x810 block/blk-cgroup.c:1206
__alloc_disk_node+0x260/0x610 block/genhd.c:1381
__blk_alloc_disk+0x35/0x70 block/genhd.c:1421
brd_alloc.part.0+0x27f/0x7a0 drivers/block/brd.c:391
brd_alloc drivers/block/brd.c:374 [inline]
brd_init+0x1b8/0x24b drivers/block/brd.c:477
do_one_initcall+0x103/0x650 init/main.c:1298
do_initcall_level init/main.c:1371 [inline]
do_initcalls init/main.c:1387 [inline]
do_basic_setup init/main.c:1406 [inline]
kernel_init_freeable+0x6b1/0x73a init/main.c:1613
kernel_init+0x1a/0x1d0 init/main.c:1502
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
-> #1 (&q->queue_lock){..-.}-{2:2}:
__raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline]
_raw_spin_lock_irq+0x32/0x50 kernel/locking/spinlock.c:170
spin_lock_irq include/linux/spinlock.h:374 [inline]
throtl_pending_timer_fn+0xf7/0x1690 block/blk-throttle.c:1152
call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1421
expire_timers kernel/time/timer.c:1466 [inline]
__run_timers.part.0+0x67c/0xa30 kernel/time/timer.c:1734
__run_timers kernel/time/timer.c:1715 [inline]
run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1747
__do_softirq+0x29b/0x9c2 kernel/softirq.c:558
invoke_softirq kernel/softirq.c:432 [inline]
__irq_exit_rcu+0x123/0x180 kernel/softirq.c:637
irq_exit_rcu+0x5/0x20 kernel/softirq.c:649
sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1097
asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:645
native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
acpi_safe_halt drivers/acpi/processor_idle.c:115 [inline]
acpi_idle_do_entry+0x1c6/0x250 drivers/acpi/processor_idle.c:556
acpi_idle_enter+0x361/0x500 drivers/acpi/processor_idle.c:691
cpuidle_enter_state+0x1b1/0xc80 drivers/cpuidle/cpuidle.c:237
cpuidle_enter+0x4a/0xa0 drivers/cpuidle/cpuidle.c:351
call_cpuidle kernel/sched/idle.c:155 [inline]
cpuidle_idle_call kernel/sched/idle.c:236 [inline]
do_idle+0x3e8/0x590 kernel/sched/idle.c:303
cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:400
start_secondary+0x265/0x340 arch/x86/kernel/smpboot.c:266
secondary_startup_64_no_verify+0xc3/0xcb
-> #0 ((&sq->pending_timer)){+.-.}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3065 [inline]
check_prevs_add kernel/locking/lockdep.c:3188 [inline]
validate_chain kernel/locking/lockdep.c:3803 [inline]
__lock_acquire+0x2ac6/0x56c0 kernel/locking/lockdep.c:5029
lock_acquire kernel/locking/lockdep.c:5641 [inline]
lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5606
del_timer_sync+0x5b/0x1b0 kernel/time/timer.c:1364
throtl_pd_free+0x15/0x40 block/blk-throttle.c:500
blkcg_deactivate_policy block/blk-cgroup.c:1445 [inline]
blkcg_deactivate_policy+0x2d2/0x4e0 block/blk-cgroup.c:1423
blk_throtl_exit+0x8a/0x1a0 block/blk-throttle.c:2335
blkcg_init_queue+0x225/0x810 block/blk-cgroup.c:1226
__alloc_disk_node+0x260/0x610 block/genhd.c:1381
__blk_mq_alloc_disk+0x133/0x1c0 block/blk-mq.c:3930
loop_add+0x33d/0x910 drivers/block/loop.c:2012
loop_control_ioctl+0x130/0x4d0 drivers/block/loop.c:2186
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl fs/ioctl.c:856 [inline]
__x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856
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
other info that might help us debug this:
Chain exists of:
(&sq->pending_timer) --> &q->queue_lock --> &blkcg->lock
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&blkcg->lock);
lock(&q->queue_lock);
lock(&blkcg->lock);
lock((&sq->pending_timer));
*** DEADLOCK ***
2 locks held by syz-executor173/3613:
#0: ffff88801dd168e0 (&q->queue_lock){..-.}-{2:2}, at: spin_lock_irq include/linux/spinlock.h:374 [inline]
#0: ffff88801dd168e0 (&q->queue_lock){..-.}-{2:2}, at: blkcg_deactivate_policy block/blk-cgroup.c:1434 [inline]
#0: ffff88801dd168e0 (&q->queue_lock){..-.}-{2:2}, at: blkcg_deactivate_policy+0xfe/0x4e0 block/blk-cgroup.c:1423
#1: ffffffff9070b710 (&blkcg->lock){....}-{2:2}, at: spin_lock include/linux/spinlock.h:349 [inline]
#1: ffffffff9070b710 (&blkcg->lock){....}-{2:2}, at: blkcg_deactivate_policy block/blk-cgroup.c:1441 [inline]
#1: ffffffff9070b710 (&blkcg->lock){....}-{2:2}, at: blkcg_deactivate_policy+0x1e7/0x4e0 block/blk-cgroup.c:1423
stack backtrace:
CPU: 1 PID: 3613 Comm: syz-executor173 Not tainted 5.18.0-rc2-syzkaller-00122-gb9b4c79e5830 #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:2145
check_prev_add kernel/locking/lockdep.c:3065 [inline]
check_prevs_add kernel/locking/lockdep.c:3188 [inline]
validate_chain kernel/locking/lockdep.c:3803 [inline]
__lock_acquire+0x2ac6/0x56c0 kernel/locking/lockdep.c:5029
lock_acquire kernel/locking/lockdep.c:5641 [inline]
lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5606
del_timer_sync+0x5b/0x1b0 kernel/time/timer.c:1364
throtl_pd_free+0x15/0x40 block/blk-throttle.c:500
blkcg_deactivate_policy block/blk-cgroup.c:1445 [inline]
blkcg_deactivate_policy+0x2d2/0x4e0 block/blk-cgroup.c:1423
blk_throtl_exit+0x8a/0x1a0 block/blk-throttle.c:2335
blkcg_init_queue+0x225/0x810 block/blk-cgroup.c:1226
__alloc_disk_node+0x260/0x610 block/genhd.c:1381
__blk_mq_alloc_disk+0x133/0x1c0 block/blk-mq.c:3930
loop_add+0x33d/0x910 drivers/block/loop.c:2012
loop_control_ioctl+0x130/0x4d0 drivers/block/loop.c:2186
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl fs/ioctl.c:856 [inline]
__x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856
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: 0033:0x7fde66153079
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 b1 14 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffcdacd33e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007fde66153079
RDX: 0000000000000000 RSI: 0000000000004c80 RDI: 0000000000000003
RBP: 00007ffcdacd3400 R08: 0000000000000002 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000004
R13: 431bde82d7b634db R14: 0000000000000000 R15: 0000000000000000
</TASK>
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
For information about bisection process see: https://goo.gl/tpsmEJ#bisection
syzbot can test patches for this issue, for details see:
https://goo.gl/tpsmEJ#testing-patches
next reply other threads:[~2022-04-15 18:29 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-15 18:29 syzbot [this message]
[not found] <20220415234011.1489-1-hdanton@sina.com>
2022-04-16 0:46 ` [syzbot] possible deadlock in blkcg_deactivate_policy syzbot
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=00000000000092e0d405dcb597d4@google.com \
--to=syzbot+b9e4c31d0a1efb34cb03@syzkaller.appspotmail.com \
--cc=axboe@kernel.dk \
--cc=cgroups@vger.kernel.org \
--cc=linux-block@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=ming.lei@redhat.com \
--cc=syzkaller-bugs@googlegroups.com \
--cc=tj@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.