[v6.6] INFO: task hung in __tun_chr_ioctl

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 5fa4793a2d2d Linux 6.6.119
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=159d2a60580000
kernel config: https://syzkaller.appspot.com/x/.config?x=691a6769a86ac817
dashboard link: https://syzkaller.appspot.com/bug?extid=8d1cb0b5aee33ab20776
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/857fe583cdec/disk-5fa4793a.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ed4d3c1402bc/vmlinux-5fa4793a.xz
kernel image: https://storage.googleapis.com/syzbot-assets/40296d968c3d/bzImage-5fa4793a.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8d1cb0...@syzkaller.appspotmail.com

INFO: task syz.5.2819:16442 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.5.2819 state:D stack:27208 pid:16442 ppid:10324 flags:0x00004004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5380 [inline]
__schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
schedule+0xbd/0x170 kernel/sched/core.c:6773
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6832
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x6b7/0xcc0 kernel/locking/mutex.c:747
__tun_chr_ioctl+0x3b9/0x1fd0 drivers/net/tun.c:3121
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:871 [inline]
__se_sys_ioctl+0xfd/0x170 fs/ioctl.c:857
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fc38d18f749
RSP: 002b:00007fc38e045038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fc38d3e5fa0 RCX: 00007fc38d18f749
RDX: 0000200000000040 RSI: 00000000400454ca RDI: 0000000000000004
RBP: 00007fc38d213f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc38d3e6038 R14: 00007fc38d3e5fa0 R15: 00007ffc27ee4998
</TASK>
INFO: task syz.5.2819:16443 blocked for more than 145 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.5.2819 state:D stack:29064 pid:16443 ppid:10324 flags:0x00004004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5380 [inline]
__schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
schedule+0xbd/0x170 kernel/sched/core.c:6773
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6832
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x6b7/0xcc0 kernel/locking/mutex.c:747
tun_detach drivers/net/tun.c:698 [inline]
tun_chr_close+0x41/0x1c0 drivers/net/tun.c:3511
__fput+0x234/0x970 fs/file_table.c:384
__do_sys_close fs/open.c:1573 [inline]
__se_sys_close+0x15f/0x220 fs/open.c:1558
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fc38d18f749
RSP: 002b:00007fc38e024038 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 00007fc38d3e6090 RCX: 00007fc38d18f749
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007fc38d213f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc38d3e6128 R14: 00007fc38d3e6090 R15: 00007ffc27ee4998
</TASK>
INFO: task syz.5.2819:16444 blocked for more than 147 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.5.2819 state:D stack:27176 pid:16444 ppid:10324 flags:0x00004004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5380 [inline]
__schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
schedule+0xbd/0x170 kernel/sched/core.c:6773
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6832
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x6b7/0xcc0 kernel/locking/mutex.c:747
dev_ioctl+0x7d2/0x1170 net/core/dev_ioctl.c:785
sock_do_ioctl+0x226/0x2f0 net/socket.c:1236
sock_ioctl+0x623/0x7a0 net/socket.c:1341
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:871 [inline]
__se_sys_ioctl+0xfd/0x170 fs/ioctl.c:857
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fc38d18f749
RSP: 002b:00007fc38e003038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fc38d3e6180 RCX: 00007fc38d18f749
RDX: 00002000000000c0 RSI: 0000000000008914 RDI: 0000000000000003
RBP: 00007fc38d213f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc38d3e6218 R14: 00007fc38d3e6180 R15: 00007ffc27ee4998
</TASK>
INFO: task syz.5.2819:16447 blocked for more than 150 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.5.2819 state:D stack:25832 pid:16447 ppid:10324 flags:0x00004004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5380 [inline]
__schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
schedule+0xbd/0x170 kernel/sched/core.c:6773
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6832
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x6b7/0xcc0 kernel/locking/mutex.c:747
tun_detach drivers/net/tun.c:698 [inline]
tun_chr_close+0x41/0x1c0 drivers/net/tun.c:3511
__fput+0x234/0x970 fs/file_table.c:384
__do_sys_close fs/open.c:1573 [inline]
__se_sys_close+0x15f/0x220 fs/open.c:1558
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fc38d18f749
RSP: 002b:00007fc38dfe2038 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 00007fc38d3e6270 RCX: 00007fc38d18f749
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000000000000a
RBP: 00007fc38d213f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc38d3e6308 R14: 00007fc38d3e6270 R15: 00007ffc27ee4998
</TASK>
INFO: task syz.5.2819:16448 blocked for more than 152 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.5.2819 state:D stack:27304 pid:16448 ppid:10324 flags:0x00004004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5380 [inline]
__schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
schedule+0xbd/0x170 kernel/sched/core.c:6773
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6832
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x6b7/0xcc0 kernel/locking/mutex.c:747


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