general protection fault in __call_rcu (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3f8a27f9e27b Linux 4.19.211
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1187a71db00000
kernel config: https://syzkaller.appspot.com/x/.config?x=9b9277b418617afe
dashboard link: https://syzkaller.appspot.com/bug?extid=6971f7284583568337c4
compiler: gcc version 10.2.1 20210110 (Debian 10.2.1-6)

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

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+6971f7...@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: 0 PID: 4700 Comm: systemd-udevd Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:lookup_object lib/debugobjects.c:156 [inline]
RIP: 0010:debug_object_activate+0x16d/0x450 lib/debugobjects.c:474
Code: 89 02 00 00 48 8b ab c0 fb 36 8d 31 db 48 85 ed 74 48 49 bd 00 00 00 00 00 fc ff df 48 8d 7d 18 83 c3 01 48 89 f8 48 c1 e8 03 <42> 80 3c 28 00 0f 85 1d 02 00 00 4c 3b 65 18 0f 84 c7 00 00 00 48
RSP: 0018:ffff88809aa27d58 EFLAGS: 00010002
RAX: 00000000169e194c RBX: 0000000000000002 RCX: ffffffff814bdebb
RDX: 1ffffffff1a74f53 RSI: 0000000000000004 RDI: 00000000b4f0ca60
RBP: 00000000b4f0ca48 R08: ffffffff8d3a7a88 R09: 0000000000000286
R10: ffffffff8d3a7a8b R11: 0000000000000000 R12: ffff888042e4d580
R13: dffffc0000000000 R14: 1ffff11013544fad R15: ffffffff89f85e80
FS: 00007f18c9b9f8c0(0000) GS:ffff8880ba000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd79b14ed0 CR3: 000000009ab45000 CR4: 00000000003426f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
debug_rcu_head_queue kernel/rcu/rcu.h:193 [inline]
__call_rcu.constprop.0+0x31/0x7f0 kernel/rcu/tree.c:2977
task_work_run+0x148/0x1c0 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:193 [inline]
exit_to_usermode_loop+0x251/0x2a0 arch/x86/entry/common.c:167
prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline]
syscall_return_slowpath arch/x86/entry/common.c:271 [inline]
do_syscall_64+0x538/0x620 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f18c89e9a07
Code: 2e 00 f7 d8 bf ff ff ff ff 64 89 02 eb d0 0f 1f 44 00 00 48 85 ff 74 3b 53 8b 1f e8 3b bf f6 ff 48 63 fb b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 09 5b c3 0f 1f 80 00 00 00 00 48 8b 15 59 54
RSP: 002b:00007ffd06363ef0 EFLAGS: 00000206 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 000000000000000f RCX: 00007f18c89e9a07
RDX: 00007f18c8cd0380 RSI: 00007f18c8ccfb58 RDI: 000000000000000f
RBP: 00007f18c9b9f710 R08: 000055f8dbf145b0 R09: 0000000000008040
R10: 00007f18c8ccfb58 R11: 0000000000000206 R12: 0000000000000000
R13: 000055f8dbef31d0 R14: 00000000000000ff R15: 000055f8dbef31d0
Modules linked in:

======================================================
----------------
Code disassembly (best guess):
0: 89 02 mov %eax,(%rdx)
2: 00 00 add %al,(%rax)
4: 48 8b ab c0 fb 36 8d mov -0x72c90440(%rbx),%rbp
b: 31 db xor %ebx,%ebx
d: 48 85 ed test %rbp,%rbp
10: 74 48 je 0x5a
12: 49 bd 00 00 00 00 00 movabs $0xdffffc0000000000,%r13
19: fc ff df
1c: 48 8d 7d 18 lea 0x18(%rbp),%rdi
20: 83 c3 01 add $0x1,%ebx
23: 48 89 f8 mov %rdi,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 42 80 3c 28 00 cmpb $0x0,(%rax,%r13,1) <-- trapping instruction
2f: 0f 85 1d 02 00 00 jne 0x252
35: 4c 3b 65 18 cmp 0x18(%rbp),%r12
39: 0f 84 c7 00 00 00 je 0x106
3f: 48 rex.W


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[syzbot]

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