[syzbot ci] Re: fuse: abort connection on /dev/fuse flush to prevent deadlock

[syzbot ci]

syzbot ci has tested the following series

[v3] fuse: abort connection on /dev/fuse flush to prevent deadlock
https://lore.kernel.org/all/40d9021a-6a93-43a1...@mail.kernel.org
* [PATCH RFC v3] fuse: abort connection on /dev/fuse flush to prevent deadlock

and found the following issue:
general protection fault in fasync_remove_entry

Full report is available here:
https://ci.syzbot.org/series/a9dcb2cb-0ef5-4576-84ff-c40a48e2a25a

***

general protection fault in fasync_remove_entry

tree: bpf-next
URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/bpf/bpf-next.git
base: 8cdeaa50eae8dad34885515f62559ee83e7e8dda
arch: amd64
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
config: https://ci.syzbot.org/builds/be2f3b2c-a8ca-4791-b9dd-8f1f9d24d9e9/config
syz repro: https://ci.syzbot.org/findings/0c2890de-1b7a-4718-a188-a597ff4d74a7/syz_repro

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000026: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000130-0x0000000000000137]
CPU: 0 UID: 0 PID: 5854 Comm: syz.1.18 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:fasync_remove_entry+0x3e/0x1c0 fs/fcntl.c:1008
Code: 49 bd 00 00 00 00 00 fc ff df e8 fd 44 7a ff 48 89 df e8 05 2e 85 09 48 c7 c7 80 65 cd 8e e8 f9 2d 85 09 4c 89 f0 48 c1 e8 03 <42> 80 3c 28 00 74 08 4c 89 f7 e8 a3 cf e7 ff 4d 8b 3e 4d 85 ff 74
RSP: 0018:ffffc900035efd38 EFLAGS: 00010202
RAX: 0000000000000026 RBX: ffff888174b8cc00 RCX: 0000000000000001
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffc900035efcc0
RBP: dffffc0000000000 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff520006bdf98 R12: ffff88810270ab80
R13: dffffc0000000000 R14: 0000000000000131 R15: ffffffff8c29b708
FS: 0000555569119500(0000) GS:ffff88818d959000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000080 CR3: 0000000102f90000 CR4: 00000000000006f0
Call Trace:
<TASK>
__fput+0x88d/0xa50 fs/file_table.c:509
task_work_run+0x1d9/0x270 kernel/task_work.c:233
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
__exit_to_user_mode_loop kernel/entry/common.c:70 [inline]
exit_to_user_mode_loop+0x1fa/0x730 kernel/entry/common.c:101
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
do_syscall_64+0x353/0x580 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc7bcb9de99
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe628b3f98 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007ffe628b4080 RCX: 00007fc7bcb9de99
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 000000000001302f R08: 0000000000000001 R09: 0000000000000000
R10: 0000001b32a20000 R11: 0000000000000246 R12: 00007ffe628b40c0
R13: 00007fc7bce25fac R14: 000000000001306b R15: 00007fc7bce25fa0
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:fasync_remove_entry+0x3e/0x1c0 fs/fcntl.c:1008
Code: 49 bd 00 00 00 00 00 fc ff df e8 fd 44 7a ff 48 89 df e8 05 2e 85 09 48 c7 c7 80 65 cd 8e e8 f9 2d 85 09 4c 89 f0 48 c1 e8 03 <42> 80 3c 28 00 74 08 4c 89 f7 e8 a3 cf e7 ff 4d 8b 3e 4d 85 ff 74
RSP: 0018:ffffc900035efd38 EFLAGS: 00010202
RAX: 0000000000000026 RBX: ffff888174b8cc00 RCX: 0000000000000001
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffc900035efcc0
RBP: dffffc0000000000 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff520006bdf98 R12: ffff88810270ab80
R13: dffffc0000000000 R14: 0000000000000131 R15: ffffffff8c29b708
FS: 0000555569119500(0000) GS:ffff88818d959000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000080 CR3: 0000000102f90000 CR4: 00000000000006f0
----------------
Code disassembly (best guess):
0: 49 bd 00 00 00 00 00 movabs $0xdffffc0000000000,%r13
7: fc ff df
a: e8 fd 44 7a ff call 0xff7a450c
f: 48 89 df mov %rbx,%rdi
12: e8 05 2e 85 09 call 0x9852e1c
17: 48 c7 c7 80 65 cd 8e mov $0xffffffff8ecd6580,%rdi
1e: e8 f9 2d 85 09 call 0x9852e1c
23: 4c 89 f0 mov %r14,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 42 80 3c 28 00 cmpb $0x0,(%rax,%r13,1) <-- trapping instruction
2f: 74 08 je 0x39
31: 4c 89 f7 mov %r14,%rdi
34: e8 a3 cf e7 ff call 0xffe7cfdc
39: 4d 8b 3e mov (%r14),%r15
3c: 4d 85 ff test %r15,%r15
3f: 74 .byte 0x74


***

If these findings have caused you to resend the series or submit a
separate fix, please add the following tag to your commit message:
Tested-by: syz...@syzkaller.appspotmail.com

---
This report is generated by a bot. It may contain errors.
syzbot ci engineers can be reached at syzk...@googlegroups.com.

To test a patch for this bug, please reply with `#syz test`
(should be on a separate line).

The patch should be attached to the email.
Note: arguments like custom git repos and branches are not supported.