[syzbot] [kernfs?] INFO: task hung in fdget_pos

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    fc20a3e57247 Merge tag 'for-linus-6.12a-rc2-tag' of git://..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=110fb307980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=9775e9a1af839423
dashboard link: https://syzkaller.appspot.com/bug?extid=0ee1ef35cf7e70ce55d7
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=11d0a79f980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/64ef5d6cfda3/disk-fc20a3e5.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/42c0ee676795/vmlinux-fc20a3e5.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a3072d6383ea/bzImage-fc20a3e5.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/a8f928c45431/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+0ee1ef35cf7e70ce55d7@xxxxxxxxxxxxxxxxxxxxxxxxx

INFO: task syz.2.17:5434 blocked for more than 159 seconds.
      Not tainted 6.12.0-rc1-syzkaller-00330-gfc20a3e57247 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.17        state:D stack:27424 pid:5434  tgid:5432  ppid:5316   flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5315 [inline]
 __schedule+0x1843/0x4ae0 kernel/sched/core.c:6675
 __schedule_loop kernel/sched/core.c:6752 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6767
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6824
 __mutex_lock_common kernel/locking/mutex.c:684 [inline]
 __mutex_lock+0x6a7/0xd70 kernel/locking/mutex.c:752
 fdget_pos+0x24e/0x320 fs/file.c:1160
 ksys_read+0x7e/0x2b0 fs/read_write.c:703
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f993c77dff9
RSP: 002b:00007f993d54e038 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f993c936058 RCX: 00007f993c77dff9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007f993c7f0296 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f993c936058 R15: 00007fffb8436518
 </TASK>
INFO: task syz.3.18:5439 blocked for more than 167 seconds.
      Not tainted 6.12.0-rc1-syzkaller-00330-gfc20a3e57247 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.18        state:D stack:27424 pid:5439  tgid:5436  ppid:5317   flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5315 [inline]
 __schedule+0x1843/0x4ae0 kernel/sched/core.c:6675
 __schedule_loop kernel/sched/core.c:6752 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6767
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6824
 __mutex_lock_common kernel/locking/mutex.c:684 [inline]
 __mutex_lock+0x6a7/0xd70 kernel/locking/mutex.c:752
 fdget_pos+0x24e/0x320 fs/file.c:1160
 ksys_read+0x7e/0x2b0 fs/read_write.c:703
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1134d7dff9
RSP: 002b:00007f1135adc038 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f1134f36058 RCX: 00007f1134d7dff9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007f1134df0296 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f1134f36058 R15: 00007ffe6e122188
 </TASK>
INFO: task syz.4.19:5441 blocked for more than 168 seconds.
      Not tainted 6.12.0-rc1-syzkaller-00330-gfc20a3e57247 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.19        state:D stack:27424 pid:5441  tgid:5438  ppid:5327   flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5315 [inline]
 __schedule+0x1843/0x4ae0 kernel/sched/core.c:6675
 __schedule_loop kernel/sched/core.c:6752 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6767
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6824
 __mutex_lock_common kernel/locking/mutex.c:684 [inline]
 __mutex_lock+0x6a7/0xd70 kernel/locking/mutex.c:752
 fdget_pos+0x24e/0x320 fs/file.c:1160
 ksys_read+0x7e/0x2b0 fs/read_write.c:703
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4c9ad7dff9
RSP: 002b:00007f4c9bc43038 EFLAGS: 00000246 ORIG_RAX: 0000000000000000


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup