[v6.1] INFO: task hung in unix_dgram_sendmsg

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 8b4118fabd6e Linux 6.1.78
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=138a83a4180000
kernel config: https://syzkaller.appspot.com/x/.config?x=88ef89f70d190671
dashboard link: https://syzkaller.appspot.com/bug?extid=0fb57e12fba9d61a975d
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: arm64

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/081869225fc6/disk-8b4118fa.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d2352caf51d2/vmlinux-8b4118fa.xz
kernel image: https://storage.googleapis.com/syzbot-assets/43ad130ed88b/Image-8b4118fa.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+0fb57e...@syzkaller.appspotmail.com

INFO: task klogd:3831 blocked for more than 143 seconds.
Not tainted 6.1.78-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:klogd state:D stack:0 pid:3831 ppid:1 flags:0x00000004
Call trace:
__switch_to+0x320/0x754 arch/arm64/kernel/process.c:553
context_switch kernel/sched/core.c:5245 [inline]
__schedule+0xee4/0x1c98 kernel/sched/core.c:6558
schedule+0xc4/0x170 kernel/sched/core.c:6634
wait_for_unix_gc+0x15c/0x218 net/unix/garbage.c:201
unix_dgram_sendmsg+0xe8/0x16c0 net/unix/af_unix.c:1899
sock_sendmsg_nosec net/socket.c:718 [inline]
__sock_sendmsg net/socket.c:730 [inline]
__sys_sendto+0x3b8/0x508 net/socket.c:2148
__do_sys_sendto net/socket.c:2160 [inline]
__se_sys_sendto net/socket.c:2156 [inline]
__arm64_sys_sendto+0xd8/0xf8 net/socket.c:2156
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
INFO: task dhcpcd:3895 blocked for more than 143 seconds.
Not tainted 6.1.78-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:dhcpcd state:D stack:0 pid:3895 ppid:1 flags:0x00000804
Call trace:
__switch_to+0x320/0x754 arch/arm64/kernel/process.c:553
context_switch kernel/sched/core.c:5245 [inline]
__schedule+0xee4/0x1c98 kernel/sched/core.c:6558
schedule+0xc4/0x170 kernel/sched/core.c:6634
wait_for_unix_gc+0x15c/0x218 net/unix/garbage.c:201
unix_dgram_sendmsg+0xe8/0x16c0 net/unix/af_unix.c:1899
sock_sendmsg_nosec net/socket.c:718 [inline]
__sock_sendmsg net/socket.c:730 [inline]
sock_write_iter+0x2d8/0x414 net/socket.c:1143
call_write_iter include/linux/fs.h:2249 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x610/0x914 fs/read_write.c:584
ksys_write+0x15c/0x26c fs/read_write.c:637
__do_sys_write fs/read_write.c:649 [inline]
__se_sys_write fs/read_write.c:646 [inline]
__arm64_sys_write+0x7c/0x90 fs/read_write.c:646
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x1fc/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
INFO: task udevd:4240 blocked for more than 143 seconds.
Not tainted 6.1.78-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd state:D stack:0 pid:4240 ppid:3842 flags:0x00000004
Call trace:
__switch_to+0x320/0x754 arch/arm64/kernel/process.c:553
context_switch kernel/sched/core.c:5245 [inline]
__schedule+0xee4/0x1c98 kernel/sched/core.c:6558
schedule+0xc4/0x170 kernel/sched/core.c:6634
wait_for_unix_gc+0x15c/0x218 net/unix/garbage.c:201
unix_dgram_sendmsg+0xe8/0x16c0 net/unix/af_unix.c:1899
sock_sendmsg_nosec net/socket.c:718 [inline]
__sock_sendmsg net/socket.c:730 [inline]
sock_write_iter+0x2d8/0x414 net/socket.c:1143
call_write_iter include/linux/fs.h:2249 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x610/0x914 fs/read_write.c:584
ksys_write+0x15c/0x26c fs/read_write.c:637
__do_sys_write fs/read_write.c:649 [inline]
__se_sys_write fs/read_write.c:646 [inline]
__arm64_sys_write+0x7c/0x90 fs/read_write.c:646
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
INFO: task udevd:4256 blocked for more than 143 seconds.
Not tainted 6.1.78-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd state:D stack:0 pid:4256 ppid:3842 flags:0x00000004
Call trace:
__switch_to+0x320/0x754 arch/arm64/kernel/process.c:553
context_switch kernel/sched/core.c:5245 [inline]
__schedule+0xee4/0x1c98 kernel/sched/core.c:6558
schedule+0xc4/0x170 kernel/sched/core.c:6634
wait_for_unix_gc+0x15c/0x218 net/unix/garbage.c:201
unix_dgram_sendmsg+0xe8/0x16c0 net/unix/af_unix.c:1899
sock_sendmsg_nosec net/socket.c:718 [inline]
__sock_sendmsg net/socket.c:730 [inline]
sock_write_iter+0x2d8/0x414 net/socket.c:1143
call_write_iter include/linux/fs.h:2249 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x610/0x914 fs/read_write.c:584
ksys_write+0x15c/0x26c fs/read_write.c:637
__do_sys_write fs/read_write.c:649 [inline]
__se_sys_write fs/read_write.c:646 [inline]
__arm64_sys_write+0x7c/0x90 fs/read_write.c:646
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
INFO: task udevd:4257 blocked for more than 143 seconds.
Not tainted 6.1.78-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd state:D stack:0 pid:4257 ppid:3842 flags:0x00000004
Call trace:
__switch_to+0x320/0x754 arch/arm64/kernel/process.c:553
context_switch kernel/sched/core.c:5245 [inline]
__schedule+0xee4/0x1c98 kernel/sched/core.c:6558
schedule+0xc4/0x170 kernel/sched/core.c:6634
wait_for_unix_gc+0x15c/0x218 net/unix/garbage.c:201
unix_dgram_sendmsg+0xe8/0x16c0 net/unix/af_unix.c:1899
sock_sendmsg_nosec net/socket.c:718 [inline]
__sock_sendmsg net/socket.c:730 [inline]
sock_write_iter+0x2d8/0x414 net/socket.c:1143
call_write_iter include/linux/fs.h:2249 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x610/0x914 fs/read_write.c:584
ksys_write+0x15c/0x26c fs/read_write.c:637
__do_sys_write fs/read_write.c:649 [inline]
__se_sys_write fs/read_write.c:646 [inline]
__arm64_sys_write+0x7c/0x90 fs/read_write.c:646
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
INFO: task udevd:4412 blocked for more than 143 seconds.
Not tainted 6.1.78-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd state:D stack:0 pid:4412 ppid:3842 flags:0x00000004
Call trace:
__switch_to+0x320/0x754 arch/arm64/kernel/process.c:553
context_switch kernel/sched/core.c:5245 [inline]
__schedule+0xee4/0x1c98 kernel/sched/core.c:6558
schedule+0xc4/0x170 kernel/sched/core.c:6634
wait_for_unix_gc+0x15c/0x218 net/unix/garbage.c:201
unix_dgram_sendmsg+0xe8/0x16c0 net/unix/af_unix.c:1899
sock_sendmsg_nosec net/socket.c:718 [inline]
__sock_sendmsg net/socket.c:730 [inline]
sock_write_iter+0x2d8/0x414 net/socket.c:1143
call_write_iter include/linux/fs.h:2249 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x610/0x914 fs/read_write.c:584
ksys_write+0x15c/0x26c fs/read_write.c:637
__do_sys_write fs/read_write.c:649 [inline]
__se_sys_write fs/read_write.c:646 [inline]
__arm64_sys_write+0x7c/0x90 fs/read_write.c:646
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
INFO: task udevd:4529 blocked for more than 143 seconds.
Not tainted 6.1.78-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd state:D stack:0 pid:4529 ppid:3842 flags:0x00000004
Call trace:
__switch_to+0x320/0x754 arch/arm64/kernel/process.c:553
context_switch kernel/sched/core.c:5245 [inline]
__schedule+0xee4/0x1c98 kernel/sched/core.c:6558
schedule+0xc4/0x170 kernel/sched/core.c:6634
wait_for_unix_gc+0x15c/0x218 net/unix/garbage.c:201
unix_dgram_sendmsg+0xe8/0x16c0 net/unix/af_unix.c:1899
sock_sendmsg_nosec net/socket.c:718 [inline]
__sock_sendmsg net/socket.c:730 [inline]
sock_write_iter+0x2d8/0x414 net/socket.c:1143
call_write_iter include/linux/fs.h:2249 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x610/0x914 fs/read_write.c:584
ksys_write+0x15c/0x26c fs/read_write.c:637
__do_sys_write fs/read_write.c:649 [inline]
__se_sys_write fs/read_write.c:646 [inline]
__arm64_sys_write+0x7c/0x90 fs/read_write.c:646
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
INFO: task udevd:4610 blocked for more than 143 seconds.
Not tainted 6.1.78-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd state:D stack:0 pid:4610 ppid:3842 flags:0x00000004
Call trace:
__switch_to+0x320/0x754 arch/arm64/kernel/process.c:553
context_switch kernel/sched/core.c:5245 [inline]
__schedule+0xee4/0x1c98 kernel/sched/core.c:6558
schedule+0xc4/0x170 kernel/sched/core.c:6634
wait_for_unix_gc+0x15c/0x218 net/unix/garbage.c:201
unix_dgram_sendmsg+0xe8/0x16c0 net/unix/af_unix.c:1899
sock_sendmsg_nosec net/socket.c:718 [inline]
__sock_sendmsg net/socket.c:730 [inline]
sock_write_iter+0x2d8/0x414 net/socket.c:1143
call_write_iter include/linux/fs.h:2249 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x610/0x914 fs/read_write.c:584
ksys_write+0x15c/0x26c fs/read_write.c:637
__do_sys_write fs/read_write.c:649 [inline]
__se_sys_write fs/read_write.c:646 [inline]
__arm64_sys_write+0x7c/0x90 fs/read_write.c:646
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
INFO: task udevd:4611 blocked for more than 143 seconds.
Not tainted 6.1.78-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd state:D stack:0 pid:4611 ppid:3842 flags:0x00000004
Call trace:
__switch_to+0x320/0x754 arch/arm64/kernel/process.c:553
context_switch kernel/sched/core.c:5245 [inline]
__schedule+0xee4/0x1c98 kernel/sched/core.c:6558
schedule+0xc4/0x170 kernel/sched/core.c:6634
wait_for_unix_gc+0x15c/0x218 net/unix/garbage.c:201
unix_dgram_sendmsg+0xe8/0x16c0 net/unix/af_unix.c:1899
sock_sendmsg_nosec net/socket.c:718 [inline]
__sock_sendmsg net/socket.c:730 [inline]
sock_write_iter+0x2d8/0x414 net/socket.c:1143
call_write_iter include/linux/fs.h:2249 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x610/0x914 fs/read_write.c:584
ksys_write+0x15c/0x26c fs/read_write.c:637
__do_sys_write fs/read_write.c:649 [inline]
__se_sys_write fs/read_write.c:646 [inline]
__arm64_sys_write+0x7c/0x90 fs/read_write.c:646
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
INFO: task udevd:4612 blocked for more than 143 seconds.
Not tainted 6.1.78-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd state:D
stack:0 pid:4612 ppid:3842 flags:0x00000004
Call trace:
__switch_to+0x320/0x754 arch/arm64/kernel/process.c:553
context_switch kernel/sched/core.c:5245 [inline]
__schedule+0xee4/0x1c98 kernel/sched/core.c:6558
schedule+0xc4/0x170 kernel/sched/core.c:6634
wait_for_unix_gc+0x15c/0x218 net/unix/garbage.c:201
unix_dgram_sendmsg+0xe8/0x16c0 net/unix/af_unix.c:1899
sock_sendmsg_nosec net/socket.c:718 [inline]
__sock_sendmsg net/socket.c:730 [inline]
sock_write_iter+0x2d8/0x414 net/socket.c:1143
call_write_iter include/linux/fs.h:2249 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x610/0x914 fs/read_write.c:584
ksys_write+0x15c/0x26c fs/read_write.c:637
__do_sys_write fs/read_write.c:649 [inline]
__se_sys_write fs/read_write.c:646 [inline]
__arm64_sys_write+0x7c/0x90 fs/read_write.c:646
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

Showing all locks held in the system:
2 locks held by kworker/u4:0/9:
1 lock held by rcu_tasks_kthre/12:
#0: ffff800015a14ef0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x44/0xcf4 kernel/rcu/tasks.h:516
1 lock held by rcu_tasks_trace/13:
#0: ffff800015a156f0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x44/0xcf4 kernel/rcu/tasks.h:516
1 lock held by khungtaskd/28:
#0: ffff800015a14d20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:317
2 locks held by getty/3990:
#0:
ffff0000d6251098
(
&tty->ldisc_sem
){++++}-{0:0}
, at: ldsem_down_read+0x3c/0x4c drivers/tty/tty_ldsem.c:340
#1: ffff80001bce02f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x414/0x1214 drivers/tty/n_tty.c:2188
3 locks held by kworker/0:7/4302:
#0: ffff0000d59a1938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2265
#1: ffff80001e507c20 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x6a8/0x1404 kernel/workqueue.c:2267
#2: ffff800017e1b1c8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:74
3 locks held by kworker/0:8/6111:
#0: ffff0000c0020d38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2265
#1: ffff800022e97c20 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work+0x6a8/0x1404 kernel/workqueue.c:2267
#2: ffff0000d7376240 (&data->fib_lock){+.+.}-{3:3}, at: nsim_fib_event_work+0x270/0x32bc drivers/net/netdevsim/fib.c:1489
1 lock held by syz-executor.1/11357:
6 locks held by syz-executor.3/12076:

=============================================



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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 8b4118fabd6e Linux 6.1.78
git tree: linux-6.1.y

console output: https://syzkaller.appspot.com/x/log.txt?x=12022f68180000

kernel config: https://syzkaller.appspot.com/x/.config?x=88ef89f70d190671
dashboard link: https://syzkaller.appspot.com/bug?extid=0fb57e12fba9d61a975d
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: arm64

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16572072180000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=114ea362180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/081869225fc6/disk-8b4118fa.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d2352caf51d2/vmlinux-8b4118fa.xz
kernel image: https://storage.googleapis.com/syzbot-assets/43ad130ed88b/Image-8b4118fa.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+0fb57e...@syzkaller.appspotmail.com

INFO: task dhcpcd:3897 blocked for more than 143 seconds.

Not tainted 6.1.78-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.

task:dhcpcd state:D stack:0 pid:3897 ppid:1 flags:0x00000804

Call trace:
__switch_to+0x320/0x754 arch/arm64/kernel/process.c:553
context_switch kernel/sched/core.c:5245 [inline]
__schedule+0xee4/0x1c98 kernel/sched/core.c:6558
schedule+0xc4/0x170 kernel/sched/core.c:6634
wait_for_unix_gc+0x15c/0x218 net/unix/garbage.c:201
unix_dgram_sendmsg+0xe8/0x16c0 net/unix/af_unix.c:1899
sock_sendmsg_nosec net/socket.c:718 [inline]
__sock_sendmsg net/socket.c:730 [inline]
sock_write_iter+0x2d8/0x414 net/socket.c:1143
call_write_iter include/linux/fs.h:2249 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x610/0x914 fs/read_write.c:584
ksys_write+0x15c/0x26c fs/read_write.c:637
__do_sys_write fs/read_write.c:649 [inline]
__se_sys_write fs/read_write.c:646 [inline]
__arm64_sys_write+0x7c/0x90 fs/read_write.c:646
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x1fc/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

Showing all locks held in the system:
2 locks held by kworker/u4:0/9:

#0: ffff0000c0029138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2265
#1: ffff800019e17c20 ((work_completion)(&(&kfence_timer)->work)){+.+.}-{0:0}, at: process_one_work+0x6a8/0x1404 kernel/workqueue.c:2267

1 lock held by rcu_tasks_kthre/12:
#0: ffff800015a14ef0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x44/0xcf4 kernel/rcu/tasks.h:516
1 lock held by rcu_tasks_trace/13:
#0: ffff800015a156f0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x44/0xcf4 kernel/rcu/tasks.h:516
1 lock held by khungtaskd/28:
#0: ffff800015a14d20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:317

2 locks held by getty/3993:
#0: ffff0000d7678098 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x3c/0x4c drivers/tty/tty_ldsem.c:340

#1: ffff80001bce02f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x414/0x1214 drivers/tty/n_tty.c:2188

1 lock held by syz-executor376/4253:

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