Re: WARNING in tracepoint_probe_unregister

[Dmitry Vyukov]

On Sun, Nov 5, 2017 at 11:05 AM, syzbot
<bot+f00b2fc1cf284703bf4107c0ea565aafd9b536d0@xxxxxxxxxxxxxxxxxxxxxxxxx>
wrote:
> Hello,
>
> syzkaller hit the following crash on
> 36ef71cae353f88fd6e095e2aaa3e5953af1685d
> git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/master
> compiler: gcc (GCC) 7.1.1 20170620
> .config is attached
> Raw console output is attached.
> C reproducer is attached
> syzkaller reproducer is attached. See https://goo.gl/kgGztJ
> for information about syzkaller reproducers
>
>
> WARNING: CPU: 1 PID: 2992 at kernel/tracepoint.c:243 tracepoint_remove_func
> kernel/tracepoint.c:243 [inline]
> WARNING: CPU: 1 PID: 2992 at kernel/tracepoint.c:243
> tracepoint_probe_unregister+0x6b3/0x870 kernel/tracepoint.c:324
> Kernel panic - not syncing: panic_on_warn set ...
>
> CPU: 1 PID: 2992 Comm: syzkaller812809 Not tainted 4.14.0-rc5-next-20171018+
> #8
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
> Call Trace:
>  __dump_stack lib/dump_stack.c:16 [inline]
>  dump_stack+0x194/0x257 lib/dump_stack.c:52
>  panic+0x1e4/0x41c kernel/panic.c:183
>  __warn+0x1c4/0x1e0 kernel/panic.c:546
>  report_bug+0x211/0x2d0 lib/bug.c:183
>  fixup_bug+0x40/0x90 arch/x86/kernel/traps.c:177
>  do_trap_no_signal arch/x86/kernel/traps.c:211 [inline]
>  do_trap+0x260/0x390 arch/x86/kernel/traps.c:260
>  do_error_trap+0x120/0x390 arch/x86/kernel/traps.c:297
>  do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:310
>  invalid_op+0x18/0x20 arch/x86/entry/entry_64.S:905
> RIP: 0010:tracepoint_remove_func kernel/tracepoint.c:243 [inline]
> RIP: 0010:tracepoint_probe_unregister+0x6b3/0x870 kernel/tracepoint.c:324
> RSP: 0018:ffff8800397df890 EFLAGS: 00010293
> RAX: ffff88003982e8c0 RBX: 00000000fffffffe RCX: ffffffff81710233
> RDX: 0000000000000000 RSI: ffffffff85b679c0 RDI: 0000000000000282
> RBP: ffff8800397df9a8 R08: 0000000000000001 R09: 1ffff100072fbe6e
> R10: ffff8800397df880 R11: 0000000000000001 R12: ffffffff8175b5e0
> R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8800397df980
>  unregister_trace_block_rq_remap include/trace/events/block.h:602 [inline]
>  blk_unregister_tracepoints+0x1e/0x160 kernel/trace/blktrace.c:1079
>  blk_trace_cleanup+0x28/0x30 kernel/trace/blktrace.c:336
>  blk_trace_remove+0x55/0x80 kernel/trace/blktrace.c:348
>  sg_ioctl+0x5eb/0x2d90 drivers/scsi/sg.c:1098
>  vfs_ioctl fs/ioctl.c:45 [inline]
>  do_vfs_ioctl+0x1b1/0x1520 fs/ioctl.c:685
>  SYSC_ioctl fs/ioctl.c:700 [inline]
>  SyS_ioctl+0x8f/0xc0 fs/ioctl.c:691
>  entry_SYSCALL_64_fastpath+0x1f/0xbe
> RIP: 0033:0x4396a9
> RSP: 002b:00007ffd4d3facb8 EFLAGS: 00000206 ORIG_RAX: 0000000000000010
> RAX: ffffffffffffffda RBX: 00000000006ccac0 RCX: 00000000004396a9
> RDX: 000000002002d000 RSI: 4000000000001276 RDI: 0000000000000004
> RBP: 0000000000000082 R08: 00000000000000fe R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000038
> R13: ffffffffffffffff R14: 0000000000401eb0 R15: 0000000000000000
> Dumping ftrace buffer:
>    (ftrace buffer empty)
> Kernel Offset: disabled
> Rebooting in 86400 seconds..


Jens, this has the same root cause as "WARNING in
tracepoint_probe_register_prio":
https://groups.google.com/forum/#!msg/syzkaller-bugs/9IolqTA_NUk/LgLFZ6hQAQAJ
right?



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