WARNING: CPU: 1 PID: 5105 at kernel/events/core.c:331 event_function_local.constprop.102+0x494/0x560 kernel/events/core.c:331 Kernel panic - not syncing: panic_on_warn set ... CPU: 1 PID: 5105 Comm: syzkaller318382 Not tainted 4.15.0-rc8+ #8 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:53 panic+0x1e4/0x41c kernel/panic.c:183 __warn+0x1dc/0x200 kernel/panic.c:547 report_bug+0x211/0x2d0 lib/bug.c:184 fixup_bug.part.11+0x37/0x80 arch/x86/kernel/traps.c:178 fixup_bug arch/x86/kernel/traps.c:247 [inline] do_error_trap+0x2d7/0x3e0 arch/x86/kernel/traps.c:296 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:315 invalid_op+0x22/0x40 arch/x86/entry/entry_64.S:1096 RIP: 0010:event_function_local.constprop.102+0x494/0x560 kernel/events/core.c:331 RSP: 0018:ffff8801db307d00 EFLAGS: 00010006 RAX: ffff8801d902a180 RBX: ffff8801d60beac0 RCX: ffffffff81862a54 RDX: 0000000000010000 RSI: ffff8801db3079f0 RDI: ffff8801d60bebc8 RBP: ffff8801db307da0 R08: 1ffff1003b660edf R09: 000000000000000c R10: ffff8801db307bb8 R11: 0000000000000044 R12: ffff8801db330e00 R13: 1ffff1003b660fa3 R14: ffff8801d90841c0 R15: ffff8801d979ce40 perf_event_disable_local kernel/events/core.c:1979 [inline] perf_pending_event+0x1e5/0x240 kernel/events/core.c:5446 irq_work_run_list+0x184/0x240 kernel/irq_work.c:155 irq_work_run+0x1d/0x50 kernel/irq_work.c:170 smp_irq_work_interrupt+0x103/0x640 arch/x86/kernel/irq_work.c:21 irq_work_interrupt+0xa9/0xb0 arch/x86/entry/entry_64.S:968 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:777 [inline] RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x5e/0xba kernel/locking/spinlock.c:184 RSP: 0018:ffff8801d4727670 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff09 RAX: dffffc0000000000 RBX: 0000000000000282 RCX: 0000000000000000 RDX: 1ffffffff0d5918d RSI: 0000000000000001 RDI: 0000000000000282 RBP: ffff8801d4727680 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801d9084978 R13: ffff8801d9084978 R14: ffff8801d90841c0 R15: 0000000000000001 try_to_wake_up+0xf9/0x1600 kernel/sched/core.c:2082 wake_up_process kernel/sched/core.c:2151 [inline] wake_up_q+0x8a/0xe0 kernel/sched/core.c:469 futex_wake+0x572/0x680 kernel/futex.c:1574 do_futex+0x11b0/0x22a0 kernel/futex.c:3549 SYSC_futex kernel/futex.c:3605 [inline] SyS_futex+0x260/0x390 kernel/futex.c:3573 entry_SYSCALL_64_fastpath+0x29/0xa0 RIP: 0033:0x446159 RSP: 002b:00007ffe873e8f78 EFLAGS: 00000202 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 00007f9b83c81700 RCX: 0000000000446159 RDX: 0000000000446159 RSI: 0000000000000001 RDI: 00000000006debe4 RBP: 00007ffe873e8fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 00007ffe873e8eff R14: 00007f9b83c819c0 R15: 0000000000000004 ====================================================== WARNING: possible circular locking dependency detected 4.15.0-rc8+ #8 Not tainted ------------------------------------------------------ syzkaller318382/5105 is trying to acquire lock: ((console_sem).lock){-.-.}, at: [<000000003463de8d>] down_trylock+0x13/0x70 kernel/locking/semaphore.c:136 but task is already holding lock: (&ctx->lock){-.-.}, at: [<00000000c5b20a00>] perf_ctx_lock kernel/events/core.c:157 [inline] (&ctx->lock){-.-.}, at: [<00000000c5b20a00>] event_function_local.constprop.102+0x20e/0x560 kernel/events/core.c:318 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&ctx->lock){-.-.}: __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:144 perf_event_context_sched_out kernel/events/core.c:2879 [inline] __perf_event_task_sched_out+0x9b6/0x14b0 kernel/events/core.c:2971 perf_event_task_sched_out include/linux/perf_event.h:1085 [inline] prepare_task_switch kernel/sched/core.c:2592 [inline] context_switch kernel/sched/core.c:2764 [inline] __schedule+0xd5c/0x2060 kernel/sched/core.c:3375 schedule+0xf5/0x430 kernel/sched/core.c:3434 freezable_schedule include/linux/freezer.h:172 [inline] futex_wait_queue_me+0x3ed/0x7e0 kernel/futex.c:2548 futex_wait+0x34b/0x9a0 kernel/futex.c:2663 do_futex+0x11ec/0x22a0 kernel/futex.c:3545 SYSC_futex kernel/futex.c:3605 [inline] SyS_futex+0x260/0x390 kernel/futex.c:3573 entry_SYSCALL_64_fastpath+0x29/0xa0 -> #2 (&rq->lock){-.-.}: __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:144 rq_lock kernel/sched/sched.h:1766 [inline] task_fork_fair+0x7a/0x690 kernel/sched/fair.c:9449 sched_fork+0x435/0xc00 kernel/sched/core.c:2404 copy_process.part.38+0x174b/0x4b20 kernel/fork.c:1722 copy_process kernel/fork.c:1565 [inline] _do_fork+0x1f7/0xfe0 kernel/fork.c:2044 kernel_thread+0x34/0x40 kernel/fork.c:2106 rest_init+0x22/0xf0 init/main.c:402 start_kernel+0x7f1/0x819 init/main.c:716 x86_64_start_reservations+0x2a/0x2c arch/x86/kernel/head64.c:378 x86_64_start_kernel+0x77/0x7a arch/x86/kernel/head64.c:359 secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:237 -> #1 (&p->pi_lock){-.-.}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x96/0xc0 kernel/locking/spinlock.c:152 try_to_wake_up+0xbc/0x1600 kernel/sched/core.c:1988 wake_up_process+0x10/0x20 kernel/sched/core.c:2151 __up.isra.0+0x1cc/0x2c0 kernel/locking/semaphore.c:262 up+0x13b/0x1d0 kernel/locking/semaphore.c:187 __up_console_sem+0xb2/0x1a0 kernel/printk/printk.c:245 console_unlock+0x538/0xd80 kernel/printk/printk.c:2248 vprintk_emit+0x4ad/0x590 kernel/printk/printk.c:1757 vprintk_default+0x28/0x30 kernel/printk/printk.c:1796 vprintk_func+0x57/0xc0 kernel/printk/printk_safe.c:379 printk+0xaa/0xca kernel/printk/printk.c:1829 regdb_fw_cb+0x1d7/0x220 net/wireless/reg.c:886 request_firmware_work_func+0x151/0x2c0 drivers/base/firmware_class.c:1365 process_one_work+0xbbf/0x1b10 kernel/workqueue.c:2113 worker_thread+0x223/0x1990 kernel/workqueue.c:2247 kthread+0x33c/0x400 kernel/kthread.c:238 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:541 -> #0 ((console_sem).lock){-.-.}: lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:3914 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x96/0xc0 kernel/locking/spinlock.c:152 down_trylock+0x13/0x70 kernel/locking/semaphore.c:136 __down_trylock_console_sem+0xa2/0x1e0 kernel/printk/printk.c:228 console_trylock+0x15/0x100 kernel/printk/printk.c:2065 vprintk_emit+0x49b/0x590 kernel/printk/printk.c:1756 vprintk_default+0x28/0x30 kernel/printk/printk.c:1796 vprintk_func+0x57/0xc0 kernel/printk/printk_safe.c:379 printk+0xaa/0xca kernel/printk/printk.c:1829 __warn+0x9e/0x200 kernel/panic.c:529 report_bug+0x211/0x2d0 lib/bug.c:184 fixup_bug.part.11+0x37/0x80 arch/x86/kernel/traps.c:178 fixup_bug arch/x86/kernel/traps.c:247 [inline] do_error_trap+0x2d7/0x3e0 arch/x86/kernel/traps.c:296 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:315 invalid_op+0x22/0x40 arch/x86/entry/entry_64.S:1096 event_function_local.constprop.102+0x494/0x560 kernel/events/core.c:331 perf_event_disable_local kernel/events/core.c:1979 [inline] perf_pending_event+0x1e5/0x240 kernel/events/core.c:5446 irq_work_run_list+0x184/0x240 kernel/irq_work.c:155 irq_work_run+0x1d/0x50 kernel/irq_work.c:170 smp_irq_work_interrupt+0x103/0x640 arch/x86/kernel/irq_work.c:21 irq_work_interrupt+0xa9/0xb0 arch/x86/entry/entry_64.S:968 arch_local_irq_restore arch/x86/include/asm/paravirt.h:777 [inline] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline] _raw_spin_unlock_irqrestore+0x5e/0xba kernel/locking/spinlock.c:184 try_to_wake_up+0xf9/0x1600 kernel/sched/core.c:2082 wake_up_process kernel/sched/core.c:2151 [inline] wake_up_q+0x8a/0xe0 kernel/sched/core.c:469 futex_wake+0x572/0x680 kernel/futex.c:1574 do_futex+0x11b0/0x22a0 kernel/futex.c:3549 SYSC_futex kernel/futex.c:3605 [inline] SyS_futex+0x260/0x390 kernel/futex.c:3573 entry_SYSCALL_64_fastpath+0x29/0xa0 other info that might help us debug this: Chain exists of: (console_sem).lock --> &rq->lock --> &ctx->lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&ctx->lock); lock(&rq->lock); lock(&ctx->lock); lock((console_sem).lock); *** DEADLOCK *** 2 locks held by syzkaller318382/5105: #0: (&cpuctx_lock){-.-.}, at: [<0000000091388292>] perf_ctx_lock kernel/events/core.c:155 [inline] #0: (&cpuctx_lock){-.-.}, at: [<0000000091388292>] event_function_local.constprop.102+0x1f7/0x560 kernel/events/core.c:318 #1: (&ctx->lock){-.-.}, at: [<00000000c5b20a00>] perf_ctx_lock kernel/events/core.c:157 [inline] #1: (&ctx->lock){-.-.}, at: [<00000000c5b20a00>] event_function_local.constprop.102+0x20e/0x560 kernel/events/core.c:318 stack backtrace: CPU: 1 PID: 5105 Comm: syzkaller318382 Not tainted 4.15.0-rc8+ #8 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:53 print_circular_bug.isra.37+0x2cd/0x2dc kernel/locking/lockdep.c:1218 check_prev_add kernel/locking/lockdep.c:1858 [inline] check_prevs_add kernel/locking/lockdep.c:1971 [inline] validate_chain kernel/locking/lockdep.c:2412 [inline] __lock_acquire+0x30a8/0x3e00 kernel/locking/lockdep.c:3426 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:3914 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x96/0xc0 kernel/locking/spinlock.c:152 down_trylock+0x13/0x70 kernel/locking/semaphore.c:136 __down_trylock_console_sem+0xa2/0x1e0 kernel/printk/printk.c:228 console_trylock+0x15/0x100 kernel/printk/printk.c:2065 vprintk_emit+0x49b/0x590 kernel/printk/printk.c:1756 vprintk_default+0x28/0x30 kernel/printk/printk.c:1796 vprintk_func+0x57/0xc0 kernel/printk/printk_safe.c:379 printk+0xaa/0xca kernel/printk/printk.c:1829 __warn+0x9e/0x200 kernel/panic.c:529 report_bug+0x211/0x2d0 lib/bug.c:184 fixup_bug.part.11+0x37/0x80 arch/x86/kernel/traps.c:178 fixup_bug arch/x86/kernel/traps.c:247 [inline] do_error_trap+0x2d7/0x3e0 arch/x86/kernel/traps.c:296 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:315 invalid_op+0x22/0x40 arch/x86/entry/entry_64.S:1096 RIP: 0010:event_function_local.constprop.102+0x494/0x560 kernel/events/core.c:331 RSP: 0018:ffff8801db307d00 EFLAGS: 00010006 RAX: ffff8801d902a180 RBX: ffff8801d60beac0 RCX: ffffffff81862a54 RDX: 0000000000010000 RSI: ffff8801db3079f0 RDI: ffff8801d60bebc8 RBP: ffff8801db307da0 R08: 1ffff1003b660edf R09: 000000000000000c R10: ffff8801db307bb8 R11: 0000000000000044 R12: ffff8801db330e00 R13: 1ffff1003b660fa3 R14: ffff8801d90841c0 R15: ffff8801d979ce40 perf_event_disable_local kernel/events/core.c:1979 [inline] perf_pending_event+0x1e5/0x240 kernel/events/core.c:5446 irq_work_run_list+0x184/0x240 kernel/irq_work.c:155 irq_work_run+0x1d/0x50 kernel/irq_work.c:170 smp_irq_work_interrupt+0x103/0x640 arch/x86/kernel/irq_work.c:21 irq_work_interrupt+0xa9/0xb0 arch/x86/entry/entry_64.S:968 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:777 [inline] RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x5e/0xba kernel/locking/spinlock.c:184 RSP: 0018:ffff8801d4727670 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff09 RAX: dffffc0000000000 RBX: 0000000000000282 RCX: 0000000000000000 RDX: 1ffffffff0d5918d RSI: 0000000000000001 RDI: 0000000000000282 RBP: ffff8801d4727680 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801d9084978 R13: ffff8801d9084978 R14: ffff8801d90841c0 R15: 0000000000000001 try_to_wake_up+0xf9/0x1600 kernel/sched/core.c:2082 wake_up_process kernel/sched/core.c:2151 [inline] wake_up_q+0x8a/0xe0 kernel/sched/core.c:469 futex_wake+0x572/0x680 kernel/futex.c:1574 do_futex+0x11b0/0x22a0 kernel/futex.c:3549 SyS_futex Lost 13 message(s)! Shutting down cpus with NMI Dumping ftrace buffer: (ftrace buffer empty) Kernel Offset: disabled Rebooting in 86400 seconds..