WARNING in _cleanup_srcu_struct

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 574823bfab82 Change mincore() to count "mapped" pages rath..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=101b7180c00000
kernel config: https://syzkaller.appspot.com/x/.config?x=d55557b516c45456
dashboard link: https://syzkaller.appspot.com/bug?extid=5a1bbe3f318ef61ece61
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

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+5a1bbe...@syzkaller.appspotmail.com

WARNING: CPU: 1 PID: 25571 at kernel/rcu/srcutree.c:381
_cleanup_srcu_struct+0x3ee/0x600 kernel/rcu/srcutree.c:384
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 25571 Comm: syz-executor4 Not tainted 4.20.0+ #13
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1db/0x2d0 lib/dump_stack.c:113
panic+0x2cb/0x65c kernel/panic.c:214
__warn.cold+0x20/0x48 kernel/panic.c:571
report_bug+0x263/0x2b0 lib/bug.c:186
fixup_bug arch/x86/kernel/traps.c:178 [inline]
fixup_bug arch/x86/kernel/traps.c:173 [inline]
do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271
do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:290
invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:973
RIP: 0010:_cleanup_srcu_struct+0x3ee/0x600 kernel/rcu/srcutree.c:381
Code: 00 49 c7 84 24 48 04 00 00 00 00 00 00 e9 b5 fe ff ff e8 05 17 e9 ff
e9 d2 fd ff ff 0f 0b e9 a4 fe ff ff 0f 0b e9 9d fe ff ff <0f> 0b e9 96 fe
ff ff 0f 0b 48 8d 9d 58 ff ff ff 48 b8 00 00 00 00
RSP: 0018:ffff888056b97928 EFLAGS: 00010202
RAX: 0000000000000001 RBX: 1ffff1100ad72f3c RCX: dffffc0000000000
RDX: 0000000000000000 RSI: ffffffff838e8df7 RDI: 0000000000000006
RBP: ffff888056b97a48 R08: ffff888054192340 R09: 0000000000000040
R10: 0000000000000001 R11: 0000000000000000 R12: ffffc90012c987f8
R13: 0000000000000000 R14: 0000000000000008 R15: 0000000000000000
cleanup_srcu_struct include/linux/srcu.h:86 [inline]
kvm_destroy_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:753 [inline]
kvm_put_kvm+0x9c0/0xff0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:769
kvm_vm_release+0x44/0x60 arch/x86/kvm/../../../virt/kvm/kvm_main.c:780
__fput+0x3c5/0xb10 fs/file_table.c:278
____fput+0x16/0x20 fs/file_table.c:309
task_work_run+0x1f4/0x2b0 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
exit_to_usermode_loop+0x32a/0x3b0 arch/x86/entry/common.c:166
prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
do_syscall_64+0x696/0x800 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x411c91
Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 94 19 00 00 c3 48
83 ec 08 e8 0a fc ff ff 48 89 04 24 b8 03 00 00 00 0f 05 <48> 8b 3c 24 48
89 c2 e8 53 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01
RSP: 002b:0000000000a4fd90 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 000000000000000a RCX: 0000000000411c91
RDX: 0000000000000000 RSI: 00000000007407b0 RDI: 0000000000000009
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000a4fcc0 R11: 0000000000000293 R12: 0000000000000000
R13: 0000000000000001 R14: 00000000000001cb R15: 0000000000000004
Kernel Offset: disabled
Rebooting in 86400 seconds..


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[syzbot]

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