====================================================== WARNING: possible circular locking dependency detected 6.0.0-syzkaller-05118-g833477fce7a1 #0 Not tainted ------------------------------------------------------ syz-executor.4/3703 is trying to acquire lock: ffff88807e5680a8 ((&sq->pending_timer)){+.-.}-{0:0}, at: del_timer_sync+0x33/0x1b0 kernel/time/timer.c:1416 but task is already holding lock: ffffffff91363270 (&blkcg->lock){....}-{2:2}, at: spin_lock include/linux/spinlock.h:349 [inline] ffffffff91363270 (&blkcg->lock){....}-{2:2}, at: blkcg_deactivate_policy block/blk-cgroup.c:1519 [inline] ffffffff91363270 (&blkcg->lock){....}-{2:2}, at: blkcg_deactivate_policy+0x181/0x470 block/blk-cgroup.c:1501 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+0x461/0x1020 block/blk-cgroup.c:344 blkcg_init_queue+0xb2/0x620 block/blk-cgroup.c:1285 __alloc_disk_node+0x29d/0x650 block/genhd.c:1367 __blk_mq_alloc_disk+0x13b/0x1f0 block/blk-mq.c:3942 floppy_alloc_disk+0x3d/0x390 drivers/block/floppy.c:4514 do_floppy_init drivers/block/floppy.c:4595 [inline] floppy_async_init+0x316/0x21ca drivers/block/floppy.c:4765 async_run_entry_fn+0x98/0x530 kernel/async.c:127 process_one_work+0x991/0x1610 kernel/workqueue.c:2289 worker_thread+0x665/0x1080 kernel/workqueue.c:2436 kthread+0x2e4/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 -> #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+0x1a0/0x6b0 kernel/time/timer.c:1474 expire_timers kernel/time/timer.c:1519 [inline] __run_timers.part.0+0x674/0xa80 kernel/time/timer.c:1790 __run_timers kernel/time/timer.c:1768 [inline] run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1803 __do_softirq+0x1d0/0x9c8 kernel/softirq.c:571 invoke_softirq kernel/softirq.c:445 [inline] __irq_exit_rcu+0x123/0x180 kernel/softirq.c:650 irq_exit_rcu+0x5/0x20 kernel/softirq.c:662 sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1107 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:649 preempt_count arch/x86/include/asm/preempt.h:27 [inline] check_kcov_mode kernel/kcov.c:166 [inline] __sanitizer_cov_trace_pc+0x7/0x60 kernel/kcov.c:200 fmul+0x19/0x260 arch/x86/crypto/curve25519-x86_64.c:161 montgomery_ladder.constprop.0+0x385/0x560 arch/x86/crypto/curve25519-x86_64.c:1098 curve25519_ever64 arch/x86/crypto/curve25519-x86_64.c:1252 [inline] curve25519_arch+0x187/0x230 arch/x86/crypto/curve25519-x86_64.c:1599 curve25519 include/crypto/curve25519.h:39 [inline] mix_dh+0x7d/0x130 drivers/net/wireguard/noise.c:411 wg_noise_handshake_create_initiation+0x29d/0x5f0 drivers/net/wireguard/noise.c:550 wg_packet_send_handshake_initiation+0x182/0x340 drivers/net/wireguard/send.c:34 wg_packet_handshake_send_worker+0x18/0x30 drivers/net/wireguard/send.c:51 process_one_work+0x991/0x1610 kernel/workqueue.c:2289 worker_thread+0x665/0x1080 kernel/workqueue.c:2436 kthread+0x2e4/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 -> #0 ((&sq->pending_timer)){+.-.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3095 [inline] check_prevs_add kernel/locking/lockdep.c:3214 [inline] validate_chain kernel/locking/lockdep.c:3829 [inline] __lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5053 lock_acquire kernel/locking/lockdep.c:5666 [inline] lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5631 del_timer_sync+0x5b/0x1b0 kernel/time/timer.c:1417 throtl_pd_free+0x15/0x40 block/blk-throttle.c:500 blkcg_deactivate_policy block/blk-cgroup.c:1523 [inline] blkcg_deactivate_policy+0x26c/0x470 block/blk-cgroup.c:1501 blk_throtl_exit+0x8a/0x1a0 block/blk-throttle.c:2337 blkcg_init_queue+0x19b/0x620 block/blk-cgroup.c:1304 __alloc_disk_node+0x29d/0x650 block/genhd.c:1367 __blk_mq_alloc_disk+0x13b/0x1f0 block/blk-mq.c:3942 loop_add+0x3e2/0xaf0 drivers/block/loop.c:1983 loop_control_ioctl+0x133/0x620 drivers/block/loop.c:2155 __do_compat_sys_ioctl+0x1c7/0x290 fs/ioctl.c:968 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x70/0x82 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-executor.4/3703: #0: ffff888021918888 (&q->queue_lock){..-.}-{2:2}, at: spin_lock_irq include/linux/spinlock.h:374 [inline] #0: ffff888021918888 (&q->queue_lock){..-.}-{2:2}, at: blkcg_deactivate_policy block/blk-cgroup.c:1512 [inline] #0: ffff888021918888 (&q->queue_lock){..-.}-{2:2}, at: blkcg_deactivate_policy+0x9b/0x470 block/blk-cgroup.c:1501 #1: ffffffff91363270 (&blkcg->lock){....}-{2:2}, at: spin_lock include/linux/spinlock.h:349 [inline] #1: ffffffff91363270 (&blkcg->lock){....}-{2:2}, at: blkcg_deactivate_policy block/blk-cgroup.c:1519 [inline] #1: ffffffff91363270 (&blkcg->lock){....}-{2:2}, at: blkcg_deactivate_policy+0x181/0x470 block/blk-cgroup.c:1501 stack backtrace: CPU: 1 PID: 3703 Comm: syz-executor.4 Not tainted 6.0.0-syzkaller-05118-g833477fce7a1 #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+0xcd/0x134 lib/dump_stack.c:106 check_noncircular+0x25f/0x2e0 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 kernel/locking/lockdep.c:3829 [inline] __lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5053 lock_acquire kernel/locking/lockdep.c:5666 [inline] lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5631 del_timer_sync+0x5b/0x1b0 kernel/time/timer.c:1417 throtl_pd_free+0x15/0x40 block/blk-throttle.c:500 blkcg_deactivate_policy block/blk-cgroup.c:1523 [inline] blkcg_deactivate_policy+0x26c/0x470 block/blk-cgroup.c:1501 blk_throtl_exit+0x8a/0x1a0 block/blk-throttle.c:2337 blkcg_init_queue+0x19b/0x620 block/blk-cgroup.c:1304 __alloc_disk_node+0x29d/0x650 block/genhd.c:1367 __blk_mq_alloc_disk+0x13b/0x1f0 block/blk-mq.c:3942 loop_add+0x3e2/0xaf0 drivers/block/loop.c:1983 loop_control_ioctl+0x133/0x620 drivers/block/loop.c:2155 __do_compat_sys_ioctl+0x1c7/0x290 fs/ioctl.c:968 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x70/0x82 RIP: 0023:0xf7fd5549 Code: 03 74 c0 01 10 05 03 74 b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 RSP: 002b:00000000f7fd05cc EFLAGS: 00000296 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000004c80 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000282 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 ---------------- Code disassembly (best guess): 0: 03 74 c0 01 add 0x1(%rax,%rax,8),%esi 4: 10 05 03 74 b8 01 adc %al,0x1b87403(%rip) # 0x1b8740d a: 10 06 adc %al,(%rsi) c: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi 10: 10 07 adc %al,(%rdi) 12: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi 16: 10 08 adc %cl,(%rax) 18: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi 1c: 00 00 add %al,(%rax) 1e: 00 00 add %al,(%rax) 20: 00 51 52 add %dl,0x52(%rcx) 23: 55 push %rbp 24: 89 e5 mov %esp,%ebp 26: 0f 34 sysenter 28: cd 80 int $0x80 * 2a: 5d pop %rbp <-- trapping instruction 2b: 5a pop %rdx 2c: 59 pop %rcx 2d: c3 retq 2e: 90 nop 2f: 90 nop 30: 90 nop 31: 90 nop 32: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi 39: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi