general protection fault in rcu_sync_func

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 97b00aff Merge tag 'gfs2-v5.3-rc2.fixes' of git://git.kern..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=114eb3b4600000
kernel config: https://syzkaller.appspot.com/x/.config?x=4c7b914a2680c9c6
dashboard link: https://syzkaller.appspot.com/bug?extid=270dd0ff8279e2159a8d
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
CC: [johan....@gmail.com linux-b...@vger.kernel.org
linux-...@vger.kernel.org mar...@holtmann.org]

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+270dd0...@syzkaller.appspotmail.com

kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 13633 Comm: syz-executor.5 Not tainted 5.3.0-rc2+ #87
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
RIP: 0010:__wake_up_common+0xdf/0x610 kernel/sched/wait.c:86
Code: 05 00 00 4c 8b 43 38 49 83 e8 18 49 8d 78 18 48 39 7d d0 0f 84 64 02
00 00 48 b8 00 00 00 00 00 fc ff df 48 89 f9 48 c1 e9 03 <80> 3c 01 00 0f
85 0b 05 00 00 49 8b 40 18 89 55 b0 31 db 49 bc 00
RSP: 0018:ffff888059d3f818 EFLAGS: 00010046
RAX: dffffc0000000000 RBX: ffff8880979930b8 RCX: 0000000000000000
RDX: 0000000000000001 RSI: 1ffffffff134b3de RDI: 0000000000000000
RBP: ffff888059d3f870 R08: ffffffffffffffe8 R09: 0000000000000000
R10: ffffed100b3a7efe R11: 0000000000000003 R12: ffff888097993100
R13: ffff8880979930b0 R14: 0000000000000000 R15: ffff8880979930b8
FS: 00007fc02310b700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc0230e9db8 CR3: 000000009fa96000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
__wake_up_locked+0x11/0x20 kernel/sched/wait.c:151
rcu_sync_func+0x16f/0x200 kernel/rcu/sync.c:87
rcu_sync_enter+0x158/0x310 kernel/rcu/sync.c:150
percpu_down_write+0x61/0x437 kernel/locking/percpu-rwsem.c:146
hci_uart_tty_close+0x154/0x280 drivers/bluetooth/hci_ldisc.c:537
tty_ldisc_close.isra.0+0x119/0x190 drivers/tty/tty_ldisc.c:494
tty_ldisc_kill+0x9c/0x160 drivers/tty/tty_ldisc.c:642
tty_ldisc_release+0xe9/0x2b0 drivers/tty/tty_ldisc.c:814
tty_release_struct+0x1b/0x50 drivers/tty/tty_io.c:1612
tty_release+0xbcb/0xe90 drivers/tty/tty_io.c:1785
__fput+0x2ff/0x890 fs/file_table.c:280
____fput+0x16/0x20 fs/file_table.c:313
task_work_run+0x145/0x1c0 kernel/task_work.c:113
get_signal+0x2078/0x2500 kernel/signal.c:2523
do_signal+0x87/0x1700 arch/x86/kernel/signal.c:815
exit_to_usermode_loop+0x286/0x380 arch/x86/entry/common.c:159
prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline]
syscall_return_slowpath arch/x86/entry/common.c:274 [inline]
do_syscall_64+0x5a9/0x6a0 arch/x86/entry/common.c:299
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x459829
Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7
48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff
ff 0f 83 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fc02310ac78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000459829
RDX: 0000000000000002 RSI: 00000000400455c8 RDI: 0000000000000003
RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fc02310b6d4
R13: 00000000004c2526 R14: 00000000004d5988 R15: 00000000ffffffff
Modules linked in:
---[ end trace 9577fa40cb98be28 ]---
RIP: 0010:__wake_up_common+0xdf/0x610 kernel/sched/wait.c:86
Code: 05 00 00 4c 8b 43 38 49 83 e8 18 49 8d 78 18 48 39 7d d0 0f 84 64 02
00 00 48 b8 00 00 00 00 00 fc ff df 48 89 f9 48 c1 e9 03 <80> 3c 01 00 0f
85 0b 05 00 00 49 8b 40 18 89 55 b0 31 db 49 bc 00
RSP: 0018:ffff888059d3f818 EFLAGS: 00010046
RAX: dffffc0000000000 RBX: ffff8880979930b8 RCX: 0000000000000000
RDX: 0000000000000001 RSI: 1ffffffff134b3de RDI: 0000000000000000
RBP: ffff888059d3f870 R08: ffffffffffffffe8 R09: 0000000000000000
R10: ffffed100b3a7efe R11: 0000000000000003 R12: ffff888097993100
R13: ffff8880979930b0 R14: 0000000000000000 R15: ffff8880979930b8
FS: 00007fc02310b700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc0230e9db8 CR3: 000000009fa96000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.