======================================================
WARNING: possible circular locking dependency detected
6.0.0-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.2/10461 is trying to acquire lock:
ffff8881470fa768 (&q->queue_lock){..-.}-{2:2}, at: spin_lock_irq include/linux/spinlock.h:374 [inline]
ffff8881470fa768 (&q->queue_lock){..-.}-{2:2}, at: throtl_pending_timer_fn+0xe9/0xfb0 block/blk-throttle.c:1152
but task is already holding lock:
ffffc900001f0be0 ((&sq->pending_timer)){+.-.}-{0:0}, at: lockdep_copy_map include/linux/lockdep.h:41 [inline]
ffffc900001f0be0 ((&sq->pending_timer)){+.-.}-{0:0}, at: call_timer_fn+0xbb/0x210 kernel/time/timer.c:1464
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 ((&sq->pending_timer)){+.-.}-{0:0}:
lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5666
del_timer_sync+0xec/0x2a0 kernel/time/timer.c:1417
throtl_pd_free+0x15/0x40 block/blk-throttle.c:500
blkcg_deactivate_policy+0x328/0x540 block/blk-cgroup.c:1523
blk_throtl_exit+0x86/0x120 block/blk-throttle.c:2337
blkcg_init_queue+0x281/0x300 block/blk-cgroup.c:1304
__alloc_disk_node+0x2ce/0x590 block/genhd.c:1367
__blk_mq_alloc_disk+0x11b/0x1e0 block/blk-mq.c:3942
loop_add+0x325/0x9b0 drivers/block/loop.c:1983
loop_control_ioctl+0x108/0x770 drivers/block/loop.c:2155
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl+0xfb/0x170 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
-> #1 (&blkcg->lock){....}-{2:2}:
lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5666
__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+0x949/0x10a0 block/blk-cgroup.c:344
blkcg_init_queue+0xb9/0x300 block/blk-cgroup.c:1285
__alloc_disk_node+0x2ce/0x590 block/genhd.c:1367
__blk_alloc_disk+0x2c/0x80 block/genhd.c:1406
brd_alloc+0x315/0x720 drivers/block/brd.c:391
brd_init+0x102/0x1c6 drivers/block/brd.c:477
do_one_initcall+0x1b9/0x3e0 init/main.c:1296
do_initcall_level+0x168/0x218 init/main.c:1369
do_initcalls+0x4b/0x8c init/main.c:1385
kernel_init_freeable+0x3f1/0x57b init/main.c:1623
kernel_init+0x19/0x2b0 init/main.c:1512
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
-> #0 (&q->queue_lock){..-.}-{2:2}:
check_prev_add kernel/locking/lockdep.c:3095 [inline]
check_prevs_add kernel/locking/lockdep.c:3214 [inline]
validate_chain+0x1873/0x6c00 kernel/locking/lockdep.c:3829
__lock_acquire+0x1292/0x1f60 kernel/locking/lockdep.c:5053
lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5666
__raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline]
_raw_spin_lock_irq+0xae/0xf0 kernel/locking/spinlock.c:170
spin_lock_irq include/linux/spinlock.h:374 [inline]
throtl_pending_timer_fn+0xe9/0xfb0 block/blk-throttle.c:1152
call_timer_fn+0xf5/0x210 kernel/time/timer.c:1474
expire_timers kernel/time/timer.c:1519 [inline]
__run_timers+0x772/0x980 kernel/time/timer.c:1790
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1803
__do_softirq+0x362/0x773 kernel/softirq.c:571
__irq_exit_rcu+0xcf/0x150 kernel/softirq.c:650
irq_exit_rcu+0x5/0x20 kernel/softirq.c:662
sysvec_apic_timer_interrupt+0x91/0xb0 arch/x86/kernel/apic/apic.c:1106
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:649
__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202
blkcg_exit_queue+0x11/0x20 block/blk-cgroup.c:1329
disk_release+0x1f8/0x3a0 block/genhd.c:1154
device_release+0x98/0x1c0
kobject_cleanup+0x235/0x470 lib/kobject.c:673
loop_remove drivers/block/loop.c:2071 [inline]
loop_control_remove drivers/block/loop.c:2119 [inline]
loop_control_ioctl+0x629/0x770 drivers/block/loop.c:2157
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl+0xfb/0x170 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
other info that might help us debug this:
Chain exists of:
&q->queue_lock --> &blkcg->lock --> (&sq->pending_timer)
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock((&sq->pending_timer));
lock(&blkcg->lock);
lock((&sq->pending_timer));
lock(&q->queue_lock);
*** DEADLOCK ***
1 lock held by syz-executor.2/10461:
#0: ffffc900001f0be0 ((&sq->pending_timer)){+.-.}-{0:0}, at: lockdep_copy_map include/linux/lockdep.h:41 [inline]
#0: ffffc900001f0be0 ((&sq->pending_timer)){+.-.}-{0:0}, at: call_timer_fn+0xbb/0x210 kernel/time/timer.c:1464
stack backtrace:
CPU: 1 PID: 10461 Comm: syz-executor.2 Not tainted 6.0.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022
Call Trace:
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1b1/0x28e lib/dump_stack.c:106
check_noncircular+0x2cc/0x390 kernel/locking/lockdep.c:2175
check_prev_add kernel/locking/lockdep.c:3095 [inline]
check_prevs_add kernel/locking/lockdep.c:3214 [inline]
validate_chain+0x1873/0x6c00 kernel/locking/lockdep.c:3829
__lock_acquire+0x1292/0x1f60 kernel/locking/lockdep.c:5053
lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5666
__raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline]
_raw_spin_lock_irq+0xae/0xf0 kernel/locking/spinlock.c:170
spin_lock_irq include/linux/spinlock.h:374 [inline]
throtl_pending_timer_fn+0xe9/0xfb0 block/blk-throttle.c:1152
call_timer_fn+0xf5/0x210 kernel/time/timer.c:1474
expire_timers kernel/time/timer.c:1519 [inline]
__run_timers+0x772/0x980 kernel/time/timer.c:1790
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1803
__do_softirq+0x362/0x773 kernel/softirq.c:571
__irq_exit_rcu+0xcf/0x150 kernel/softirq.c:650
irq_exit_rcu+0x5/0x20 kernel/softirq.c:662
sysvec_apic_timer_interrupt+0x91/0xb0 arch/x86/kernel/apic/apic.c:1106
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:649
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202
Code: 00 00 00 00 00 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 ee 0b 3c f7 48 89 df e8 96 95 3d f7 e8 91 6b 62 f7 fb bf 01 00 00 00 26 1d 30 f7 65 8b 05 17 a4 d6 75 85 c0 74 02 5b c3 e8 84 bb d4
RSP: 0018:ffffc90006a87d40 EFLAGS: 00000286
RAX: 18ff864d5c80c600 RBX: ffff8881470fa750 RCX: ffffffff915fff03
RDX: dffffc0000000000 RSI: ffffffff8a8d9060 RDI: 0000000000000001
RBP: 1ffff11003d8a610 R08: dffffc0000000000 R09: ffffed1028e1f4eb
R10: ffffed1028e1f4eb R11: 1ffff11028e1f4ea R12: ffff88801ec53000
R13: dffffc0000000000 R14: ffff88801ec53080 R15: 1ffff11003d8a612
blkcg_exit_queue+0x11/0x20 block/blk-cgroup.c:1329
disk_release+0x1f8/0x3a0 block/genhd.c:1154
device_release+0x98/0x1c0
kobject_cleanup+0x235/0x470 lib/kobject.c:673
loop_remove drivers/block/loop.c:2071 [inline]
loop_control_remove drivers/block/loop.c:2119 [inline]
loop_control_ioctl+0x629/0x770 drivers/block/loop.c:2157
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl+0xfb/0x170 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f931e68a5a9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f931f732168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f931e7abf80 RCX: 00007f931e68a5a9
RDX: 0000000000000000 RSI: 0000000000004c81 RDI: 0000000000000003
RBP: 00007f931e6e5580 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fffb2133b4f R14: 00007f931f732300 R15: 0000000000022000
----------------
Code disassembly (best guess):
0: 00 00 add %al,(%rax)
2: 00 00 add %al,(%rax)
4: 00 53 48 add %dl,0x48(%rbx)
7: 89 fb mov %edi,%ebx
9: 48 83 c7 18 add $0x18,%rdi
d: 48 8b 74 24 08 mov 0x8(%rsp),%rsi
12: e8 ee 0b 3c f7 callq 0xf73c0c05
17: 48 89 df mov %rbx,%rdi
1a: e8 96 95 3d f7 callq 0xf73d95b5
1f: e8 91 6b 62 f7 callq 0xf7626bb5
24: fb sti
25: bf 01 00 00 00 mov $0x1,%edi
* 2a: e8 26 1d 30 f7 callq 0xf7301d55 <-- trapping instruction
2f: 65 8b 05 17 a4 d6 75 mov %gs:0x75d6a417(%rip),%eax # 0x75d6a44d
36: 85 c0 test %eax,%eax
38: 74 02 je 0x3c
3a: 5b pop %rbx
3b: c3 retq
3c: e8 .byte 0xe8
3d: 84 .byte 0x84
3e: bb .byte 0xbb
3f: d4 (bad)