======================================================
WARNING: possible circular locking dependency detected
6.1.16-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.5/7219 is trying to acquire lock:
ffff0000d8cd80a8 ((&sq->pending_timer)){+.-.}-{0:0}, at: del_timer_sync+0x74/0x210 kernel/time/timer.c:1417
but task is already holding lock:
ffff0000c2b37930 (&blkcg->lock){....}-{2:2}, at: spin_lock include/linux/spinlock.h:350 [inline]
ffff0000c2b37930 (&blkcg->lock){....}-{2:2}, at: blkcg_deactivate_policy+0x1b8/0x4bc block/blk-cgroup.c:1495
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+0x54/0x6c kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:350 [inline]
blkg_create+0x9f4/0x1158 block/blk-cgroup.c:336
blkcg_init_disk+0xe4/0x32c block/blk-cgroup.c:1260
__alloc_disk_node+0x26c/0x484 block/genhd.c:1385
__blk_alloc_disk+0x40/0xbc block/genhd.c:1424
brd_alloc+0x2ac/0x5c8 drivers/block/brd.c:397
brd_init+0x108/0x1c4 drivers/block/brd.c:484
do_one_initcall+0x310/0xda4 init/main.c:1303
do_initcall_level+0x154/0x214 init/main.c:1376
do_initcalls+0x58/0xac init/main.c:1392
do_basic_setup+0x8c/0xa0 init/main.c:1411
kernel_init_freeable+0x3a4/0x528 init/main.c:1631
kernel_init+0x24/0x29c init/main.c:1519
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:860
-> #1 (&q->queue_lock){..-.}-{2:2}:
__raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline]
_raw_spin_lock_irq+0x70/0x9c kernel/locking/spinlock.c:170
spin_lock_irq include/linux/spinlock.h:375 [inline]
throtl_pending_timer_fn+0x104/0xdcc block/blk-throttle.c:1193
call_timer_fn+0x270/0xcf4 kernel/time/timer.c:1474
expire_timers kernel/time/timer.c:1519 [inline]
__run_timers+0x554/0x718 kernel/time/timer.c:1790
run_timer_softirq+0x7c/0x114 kernel/time/timer.c:1803
__do_softirq+0x37c/0xff4 kernel/softirq.c:571
____do_softirq+0x14/0x20 arch/arm64/kernel/irq.c:79
call_on_irq_stack+0x2c/0x54 arch/arm64/kernel/entry.S:889
do_softirq_own_stack+0x20/0x2c arch/arm64/kernel/irq.c:84
invoke_softirq kernel/softirq.c:452 [inline]
__irq_exit_rcu+0x28c/0x534 kernel/softirq.c:650
irq_exit_rcu+0x14/0x84 kernel/softirq.c:662
el0_interrupt+0x80/0x260 arch/arm64/kernel/entry-common.c:717
__el0_irq_handler_common+0x18/0x24 arch/arm64/kernel/entry-common.c:724
el0t_64_irq_handler+0x10/0x1c arch/arm64/kernel/entry-common.c:729
el0t_64_irq+0x18c/0x190 arch/arm64/kernel/entry.S:582
-> #0 ((&sq->pending_timer)){+.-.}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3098 [inline]
check_prevs_add kernel/locking/lockdep.c:3217 [inline]
validate_chain kernel/locking/lockdep.c:3832 [inline]
__lock_acquire+0x3338/0x764c kernel/locking/lockdep.c:5056
lock_acquire+0x300/0x8e4 kernel/locking/lockdep.c:5669
del_timer_sync+0x9c/0x210 kernel/time/timer.c:1417
throtl_pd_free+0x20/0x48 block/blk-throttle.c:493
blkcg_deactivate_policy+0x2d8/0x4bc block/blk-cgroup.c:1499
blk_throtl_exit+0x9c/0x13c block/blk-throttle.c:2406
blkcg_exit_disk+0x4c/0x5c block/blk-cgroup.c:1301
disk_release+0x170/0x2d8 block/genhd.c:1171
device_release+0x8c/0x1ac
kobject_cleanup lib/kobject.c:681 [inline]
kobject_release lib/kobject.c:712 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x2a8/0x41c lib/kobject.c:729
put_device+0x28/0x40 drivers/base/core.c:3772
put_disk+0x4c/0x64 block/genhd.c:1450
loop_remove drivers/block/loop.c:2080 [inline]
loop_control_remove drivers/block/loop.c:2128 [inline]
loop_control_ioctl+0x534/0x650 drivers/block/loop.c:2166
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl fs/ioctl.c:856 [inline]
__arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:856
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:581
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 ***
3 locks held by syz-executor.5/7219:
#0: ffff0000cc1f02e0 (&q->blkcg_mutex){+.+.}-{3:3}, at: blkcg_deactivate_policy+0xfc/0x4bc block/blk-cgroup.c:1487
#1: ffff0000cc1f00d0 (&q->queue_lock){..-.}-{2:2}, at: spin_lock_irq include/linux/spinlock.h:375 [inline]
#1: ffff0000cc1f00d0 (&q->queue_lock){..-.}-{2:2}, at: blkcg_deactivate_policy+0x108/0x4bc block/blk-cgroup.c:1488
#2: ffff0000c2b37930 (&blkcg->lock){....}-{2:2}, at: spin_lock include/linux/spinlock.h:350 [inline]
#2: ffff0000c2b37930 (&blkcg->lock){....}-{2:2}, at: blkcg_deactivate_policy+0x1b8/0x4bc block/blk-cgroup.c:1495
stack backtrace:
CPU: 1 PID: 7219 Comm: syz-executor.5 Not tainted 6.1.16-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
Call trace:
dump_backtrace+0x1c8/0x1f4 arch/arm64/kernel/stacktrace.c:158
show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
dump_stack+0x1c/0x5c lib/dump_stack.c:113
print_circular_bug+0x150/0x1b8 kernel/locking/lockdep.c:2056
check_noncircular+0x2cc/0x378 kernel/locking/lockdep.c:2178
check_prev_add kernel/locking/lockdep.c:3098 [inline]
check_prevs_add kernel/locking/lockdep.c:3217 [inline]
validate_chain kernel/locking/lockdep.c:3832 [inline]
__lock_acquire+0x3338/0x764c kernel/locking/lockdep.c:5056
lock_acquire+0x300/0x8e4 kernel/locking/lockdep.c:5669
del_timer_sync+0x9c/0x210 kernel/time/timer.c:1417
throtl_pd_free+0x20/0x48 block/blk-throttle.c:493
blkcg_deactivate_policy+0x2d8/0x4bc block/blk-cgroup.c:1499
blk_throtl_exit+0x9c/0x13c block/blk-throttle.c:2406
blkcg_exit_disk+0x4c/0x5c block/blk-cgroup.c:1301
disk_release+0x170/0x2d8 block/genhd.c:1171
device_release+0x8c/0x1ac
kobject_cleanup lib/kobject.c:681 [inline]
kobject_release lib/kobject.c:712 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x2a8/0x41c lib/kobject.c:729
put_device+0x28/0x40 drivers/base/core.c:3772
put_disk+0x4c/0x64 block/genhd.c:1450
loop_remove drivers/block/loop.c:2080 [inline]
loop_control_remove drivers/block/loop.c:2128 [inline]
loop_control_ioctl+0x534/0x650 drivers/block/loop.c:2166
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl fs/ioctl.c:856 [inline]
__arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:856
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:581