======================================================
WARNING: possible circular locking dependency detected
6.1.16-syzkaller #0 Not tainted
------------------------------------------------------
kworker/1:10/6138 is trying to acquire lock:
ffff888021417530 (&q->queue_lock){..-.}-{2:2}, at: spin_lock_irq include/linux/spinlock.h:375 [inline]
ffff888021417530 (&q->queue_lock){..-.}-{2:2}, at: throtl_pending_timer_fn+0x10d/0x1be0 block/blk-throttle.c:1193
but task is already holding lock:
ffffc900001e0bc0 ((&sq->pending_timer)){+.-.}-{0:0}, at: lockdep_copy_map include/linux/lockdep.h:41 [inline]
ffffc900001e0bc0 ((&sq->pending_timer)){+.-.}-{0:0}, at: call_timer_fn+0xbd/0x840 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+0x23a/0x630 kernel/locking/lockdep.c:5669
del_timer_sync+0x111/0x2e0 kernel/time/timer.c:1417
throtl_pd_free+0x15/0x40 block/blk-throttle.c:493
blkcg_deactivate_policy+0x32d/0x550 block/blk-cgroup.c:1499
blk_throtl_exit+0xa6/0x140 block/blk-throttle.c:2406
disk_release+0x1dd/0x380 block/genhd.c:1171
device_release+0x91/0x1c0
kobject_cleanup lib/kobject.c:681 [inline]
kobject_release lib/kobject.c:712 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x224/0x460 lib/kobject.c:729
do_floppy_init+0x373/0xc59 drivers/block/floppy.c:4758
async_run_entry_fn+0xa2/0x410 kernel/async.c:127
process_one_work+0x909/0x1380 kernel/workqueue.c:2289
worker_thread+0xa5f/0x1210 kernel/workqueue.c:2436
kthread+0x268/0x300 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
-> #1 (&blkcg->lock){....}-{2:2}:
lock_acquire+0x23a/0x630 kernel/locking/lockdep.c:5669
__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:350 [inline]
blkg_create+0xa94/0x1280 block/blk-cgroup.c:336
blkcg_init_disk+0xee/0x350 block/blk-cgroup.c:1260
__alloc_disk_node+0x2ce/0x590 block/genhd.c:1385
__blk_alloc_disk+0x2c/0x80 block/genhd.c:1424
brd_alloc+0x2f9/0x6a0 drivers/block/brd.c:397
brd_init+0x100/0x1c2 drivers/block/brd.c:484
do_one_initcall+0x2d6/0xa80 init/main.c:1303
do_initcall_level+0x157/0x207 init/main.c:1376
do_initcalls+0x49/0x86 init/main.c:1392
kernel_init_freeable+0x473/0x61f init/main.c:1631
kernel_init+0x19/0x290 init/main.c:1519
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:3098 [inline]
check_prevs_add kernel/locking/lockdep.c:3217 [inline]
validate_chain+0x1667/0x58e0 kernel/locking/lockdep.c:3832
__lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5056
lock_acquire+0x23a/0x630 kernel/locking/lockdep.c:5669
__raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline]
_raw_spin_lock_irq+0xcf/0x110 kernel/locking/spinlock.c:170
spin_lock_irq include/linux/spinlock.h:375 [inline]
throtl_pending_timer_fn+0x10d/0x1be0 block/blk-throttle.c:1193
call_timer_fn+0x200/0x840 kernel/time/timer.c:1474
expire_timers kernel/time/timer.c:1519 [inline]
__run_timers+0x67c/0x890 kernel/time/timer.c:1790
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1803
__do_softirq+0x30d/0xb1b kernel/softirq.c:571
invoke_softirq kernel/softirq.c:445 [inline]
__irq_exit_rcu+0x155/0x240 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:1107
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:649
rep_nop arch/x86/include/asm/vdso/processor.h:13 [inline]
delay_tsc+0x58/0xd0 arch/x86/lib/delay.c:78
try_check_zero+0x3ee/0x410 kernel/rcu/srcutree.c:975
srcu_advance_state kernel/rcu/srcutree.c:1522 [inline]
process_srcu+0x1dc/0x1300 kernel/rcu/srcutree.c:1623
process_one_work+0x909/0x1380 kernel/workqueue.c:2289
worker_thread+0xa5f/0x1210 kernel/workqueue.c:2436
kthread+0x268/0x300 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
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 ***
4 locks held by kworker/1:10/6138:
#0: ffff888012466538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x77b/0x1380
#1: ffffc9000534fd20 ((work_completion)(&(&ssp->work)->work)){+.+.}-{0:0}, at: process_one_work+0x7be/0x1380 kernel/workqueue.c:2264
#2: ffffffff91b2bed8 (&ssp->srcu_gp_mutex){+.+.}-{3:3}, at: srcu_advance_state kernel/rcu/srcutree.c:1471 [inline]
#2: ffffffff91b2bed8 (&ssp->srcu_gp_mutex){+.+.}-{3:3}, at: process_srcu+0x2f/0x1300 kernel/rcu/srcutree.c:1623
#3: ffffc900001e0bc0 ((&sq->pending_timer)){+.-.}-{0:0}, at: lockdep_copy_map include/linux/lockdep.h:41 [inline]
#3: ffffc900001e0bc0 ((&sq->pending_timer)){+.-.}-{0:0}, at: call_timer_fn+0xbd/0x840 kernel/time/timer.c:1464
stack backtrace:
CPU: 1 PID: 6138 Comm: kworker/1:10 Not tainted 6.1.16-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
Workqueue: rcu_gp process_srcu
Call Trace:
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
check_noncircular+0x2fa/0x3b0 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+0x1667/0x58e0 kernel/locking/lockdep.c:3832
__lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5056
lock_acquire+0x23a/0x630 kernel/locking/lockdep.c:5669
__raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline]
_raw_spin_lock_irq+0xcf/0x110 kernel/locking/spinlock.c:170
spin_lock_irq include/linux/spinlock.h:375 [inline]
throtl_pending_timer_fn+0x10d/0x1be0 block/blk-throttle.c:1193
call_timer_fn+0x200/0x840 kernel/time/timer.c:1474
expire_timers kernel/time/timer.c:1519 [inline]
__run_timers+0x67c/0x890 kernel/time/timer.c:1790
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1803
__do_softirq+0x30d/0xb1b kernel/softirq.c:571
invoke_softirq kernel/softirq.c:445 [inline]
__irq_exit_rcu+0x155/0x240 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:1107
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:649
RIP: 0010:delay_tsc+0x58/0xd0 arch/x86/lib/delay.c:79
Code: 90 48 89 d5 48 c1 e5 20 48 09 c5 48 29 dd 4c 39 f5 73 67 bf 01 00 00 00 e8 a5 79 d7 f6 65 8b 05 e6 89 7b 75 85 c0 74 2f f3 90 01 00 00 00 e8 0e 78 d7 f6 e8 29 f2 02 00 41 39 c7 75 20 0f 01
RSP: 0018:ffffc9000534faf0 EFLAGS: 00000286
RAX: 0000000080000000 RBX: 000005266970573e RCX: 0000000000000001
RDX: 0000000000000526 RSI: ffffffff8b3d0b80 RDI: 0000000000000001
RBP: 00000000000015c6 R08: ffffffff843923c4 R09: fffffbfff1ca5386
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffffffff1ca53c7
R13: 000000000005aaf6 R14: 0000000000002af9 R15: 0000000000000001
try_check_zero+0x3ee/0x410 kernel/rcu/srcutree.c:975
srcu_advance_state kernel/rcu/srcutree.c:1522 [inline]
process_srcu+0x1dc/0x1300 kernel/rcu/srcutree.c:1623
process_one_work+0x909/0x1380 kernel/workqueue.c:2289
worker_thread+0xa5f/0x1210 kernel/workqueue.c:2436
kthread+0x268/0x300 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
----------------
Code disassembly (best guess):
0: 90 nop
1: 48 89 d5 mov %rdx,%rbp
4: 48 c1 e5 20 shl $0x20,%rbp
8: 48 09 c5 or %rax,%rbp
b: 48 29 dd sub %rbx,%rbp
e: 4c 39 f5 cmp %r14,%rbp
11: 73 67 jae 0x7a
13: bf 01 00 00 00 mov $0x1,%edi
18: e8 a5 79 d7 f6 callq 0xf6d779c2
1d: 65 8b 05 e6 89 7b 75 mov %gs:0x757b89e6(%rip),%eax # 0x757b8a0a
24: 85 c0 test %eax,%eax
26: 74 2f je 0x57
28: f3 90 pause
* 2a: bf 01 00 00 00 mov $0x1,%edi <-- trapping instruction
2f: e8 0e 78 d7 f6 callq 0xf6d77842
34: e8 29 f2 02 00 callq 0x2f262
39: 41 39 c7 cmp %eax,%r15d
3c: 75 20 jne 0x5e
3e: 0f .byte 0xf
3f: 01 .byte 0x1