BUG: unable to handle kernel NULL pointer dereference in quarantine_remove_cache

[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=143106b5b00000
kernel config: https://syzkaller.appspot.com/x/.config?x=9b9277b418617afe
dashboard link: https://syzkaller.appspot.com/bug?extid=dfad424cc563afc27049
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+dfad42...@syzkaller.appspotmail.com

input: syz1 as /devices/virtual/input/input33
BUG: unable to handle kernel NULL pointer dereference at 0000000000000014
PGD b45cb067 P4D b45cb067 PUD 0
Oops: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 8120 Comm: syz-executor.5 Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:qlist_move_cache+0x93/0xd0 mm/kasan/quarantine.c:279
Code: 3f 4c 89 ef e8 ce ea 92 ff 48 c1 e8 0c 48 c1 e0 06 4c 01 e0 48 8b 50 08 48 8d 4a ff 83 e2 01 48 0f 45 c1 48 8b 40 18 48 39 c5 <8b> 50 14 75 aa 48 83 3b 00 74 2c 48 8b 43 08 4c 89 28 4c 89 6b 08
RSP: 0018:ffff8880b301fb78 EFLAGS: 00010082
RAX: 0000000000000000 RBX: ffff8880b301fbb0 RCX: ffffea0000000007
RDX: 0000000000000000 RSI: ffffffff812b5eca RDI: 0000000000000007
RBP: ffff8880a2198940 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000007 R11: 0000000000000000 R12: ffffea0000000000
R13: ffff888000000000 R14: ffffffff8d25a6c8 R15: f000ff53f000ff53
FS: 0000555556a26400(0000) GS:ffff8880ba000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000014 CR3: 000000009d804000 CR4: 00000000003426f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
quarantine_remove_cache+0x73/0x100 mm/kasan/quarantine.c:317
shutdown_cache+0xe/0x1e0 mm/slab_common.c:562
kmem_cache_destroy+0x267/0x310 mm/slab_common.c:927
p9_client_destroy+0x250/0x360 net/9p/client.c:1112
v9fs_session_close+0x45/0x2c0 fs/9p/v9fs.c:513
v9fs_kill_super+0x49/0x90 fs/9p/vfs_super.c:233
deactivate_locked_super+0x94/0x160 fs/super.c:329
deactivate_super+0x174/0x1a0 fs/super.c:360
cleanup_mnt+0x1a8/0x290 fs/namespace.c:1098
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: 0033:0x7f6fcf45b307
Code: ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fffd45738c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f6fcf45b307
RDX: 00007fffd457399c RSI: 000000000000000a RDI: 00007fffd4573990
RBP: 00007fffd4573990 R08: 00000000ffffffff R09: 00007fffd4573760
R10: 0000555556a27903 R11: 0000000000000246 R12: 00007f6fcf4b3172
R13: 00007fffd4574a50 R14: 0000555556a27810 R15: 00007fffd4574a90
Modules linked in:
CR2: 0000000000000014
---[ end trace 233288170173f459 ]---
RIP: 0010:qlist_move_cache+0x93/0xd0 mm/kasan/quarantine.c:279
Code: 3f 4c 89 ef e8 ce ea 92 ff 48 c1 e8 0c 48 c1 e0 06 4c 01 e0 48 8b 50 08 48 8d 4a ff 83 e2 01 48 0f 45 c1 48 8b 40 18 48 39 c5 <8b> 50 14 75 aa 48 83 3b 00 74 2c 48 8b 43 08 4c 89 28 4c 89 6b 08
RSP: 0018:ffff8880b301fb78 EFLAGS: 00010082
RAX: 0000000000000000 RBX: ffff8880b301fbb0 RCX: ffffea0000000007
RDX: 0000000000000000 RSI: ffffffff812b5eca RDI: 0000000000000007
RBP: ffff8880a2198940 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000007 R11: 0000000000000000 R12: ffffea0000000000
R13: ffff888000000000 R14: ffffffff8d25a6c8 R15: f000ff53f000ff53
FS: 0000555556a26400(0000) GS:ffff8880ba000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000014 CR3: 000000009d804000 CR4: 00000000003426f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
----------------
Code disassembly (best guess), 1 bytes skipped:
0: 4c 89 ef mov %r13,%rdi
3: e8 ce ea 92 ff callq 0xff92ead6
8: 48 c1 e8 0c shr $0xc,%rax
c: 48 c1 e0 06 shl $0x6,%rax
10: 4c 01 e0 add %r12,%rax
13: 48 8b 50 08 mov 0x8(%rax),%rdx
17: 48 8d 4a ff lea -0x1(%rdx),%rcx
1b: 83 e2 01 and $0x1,%edx
1e: 48 0f 45 c1 cmovne %rcx,%rax
22: 48 8b 40 18 mov 0x18(%rax),%rax
26: 48 39 c5 cmp %rax,%rbp
* 29: 8b 50 14 mov 0x14(%rax),%edx <-- trapping instruction
2c: 75 aa jne 0xffffffd8
2e: 48 83 3b 00 cmpq $0x0,(%rbx)
32: 74 2c je 0x60
34: 48 8b 43 08 mov 0x8(%rbx),%rax
38: 4c 89 28 mov %r13,(%rax)
3b: 4c 89 6b 08 mov %r13,0x8(%rbx)


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[syzbot]

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