Date:   Sat, 27 Jan 2018 11:58:02 -0800
From:   syzbot <syzbot+352bd10e338d9a90e5e0@...kaller.appspotmail.com>
To:     acme@...nel.org, alexander.shishkin@...ux.intel.com,
        jolsa@...hat.com, linux-kernel@...r.kernel.org, mingo@...hat.com,
        namhyung@...nel.org, peterz@...radead.org,
        syzkaller-bugs@...glegroups.com
Subject: WARNING in event_function_local

Hello,

syzbot hit the following crash on bpf-next commit
8223967fe0b8eb2448cca5cfe3c64a0838e6f60d (Sat Jan 27 01:06:23 2018 +0000)
Merge branch 'fix-lpm-map'

So far this crash happened 2 times on bpf-next.
C reproducer is attached.
syzkaller reproducer is attached.
Raw console output is attached.
compiler: gcc (GCC) 7.1.1 20170620
.config is attached.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+352bd10e338d9a90e5e0@...kaller.appspotmail.com
It will help syzbot understand when the bug is fixed. See footer for  
details.
If you forward the report, please keep this part and the footer.

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:
  <IRQ>
  __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
  </IRQ>
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:
  <IRQ>
  __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
  </IRQ>
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..


---
This bug is generated by a dumb bot. It may contain errors.
See https://goo.gl/tpsmEJ for details.
Direct all questions to syzkaller@...glegroups.com.

syzbot will keep track of this bug report.
If you forgot to add the Reported-by tag, once the fix for this bug is  
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