[v5.15] INFO: task hung in xt_find_table
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syzbot
Jul 21, 2026, 12:32:30 AM (yesterday) Jul 21
to syzkaller...@googlegroups.com
Hello,
syzbot found the following issue on:
HEAD commit: c86c4726e7f0 Linux 5.15.211
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=17d57789580000
kernel config: https://syzkaller.appspot.com/x/.config?x=6f8e2266b61925dc
dashboard link: https://syzkaller.appspot.com/bug?extid=50b2c1e0c613accaa3b9
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c3e980557785/disk-c86c4726.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/5fbaf3714ad0/vmlinux-c86c4726.xz
kernel image: https://storage.googleapis.com/syzbot-assets/de60a4f1e940/bzImage-c86c4726.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+50b2c1...@syzkaller.appspotmail.com
INFO: task kworker/u4:8:4293 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:8 state:D stack:18592 pid: 4293 ppid: 2 flags:0x00004000
Workqueue: netns cleanup_net
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11c3/0x4350 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
__mutex_lock_common+0xdf5/0x2400 kernel/locking/mutex.c:669
__mutex_lock kernel/locking/mutex.c:729 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
xt_find_table+0x43/0xc0 net/netfilter/x_tables.c:1244
arpt_unregister_table_pre_exit+0x20/0xb0 net/ipv4/netfilter/arp_tables.c:1582
ops_pre_exit_list net/core/net_namespace.c:162 [inline]
cleanup_net+0x58e/0xba0 net/core/net_namespace.c:615
process_one_work+0x867/0xff0 kernel/workqueue.c:2310
worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
kthread+0x42e/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
</TASK>
Showing all locks held in the system:
2 locks held by init/1:
#0: ffff88802c2a7128 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88802c2a7128 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:4654 [inline]
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim mm/page_alloc.c:4678 [inline]
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath+0x1017/0x2700 mm/page_alloc.c:5128
1 lock held by khungtaskd/27:
#0: ffffffff8c31ef20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
3 locks held by kswapd1/255:
2 locks held by klogd/3549:
2 locks held by udevd/3560:
#0: ffff88807eb6e328 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88807eb6e328 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:4654 [inline]
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim mm/page_alloc.c:4678 [inline]
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath+0x1017/0x2700 mm/page_alloc.c:5128
2 locks held by dhcpcd/3852:
#0: ffff88801e9f1d28 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88801e9f1d28 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:4654 [inline]
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim mm/page_alloc.c:4678 [inline]
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath+0x1017/0x2700 mm/page_alloc.c:5128
2 locks held by crond/3927:
#0: ffff88801eeb8128 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88801eeb8128 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:4654 [inline]
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim mm/page_alloc.c:4678 [inline]
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath+0x1017/0x2700 mm/page_alloc.c:5128
2 locks held by getty/3945:
#0: ffff88814cd3b098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
#1: ffffc90002cf62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x594/0x1a50 drivers/tty/n_tty.c:2158
2 locks held by sshd-session/4174:
2 locks held by syz-executor/4175:
#0: ffff88807b475528 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88807b475528 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:4654 [inline]
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim mm/page_alloc.c:4678 [inline]
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath+0x1017/0x2700 mm/page_alloc.c:5128
4 locks held by kworker/u4:8/4293:
#0: ffff888016dcd938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
#1: ffffc9000329fd00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
#2: ffffffff8d43f210 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x148/0xba0 net/core/net_namespace.c:589
#3: ffff88814c8f8458 (&xt[i].mutex){+.+.}-{3:3}, at: xt_find_table+0x43/0xc0 net/netfilter/x_tables.c:1244
3 locks held by udevd/4319:
#0: ffff88807c49ed48 (&tsk->futex_exit_mutex){+.+.}-{3:3}, at: futex_cleanup_begin kernel/futex/core.c:3894 [inline]
#0: ffff88807c49ed48 (&tsk->futex_exit_mutex){+.+.}-{3:3}, at: futex_exit_release+0x2f/0x1c0 kernel/futex/core.c:3946
#1: ffff88807b471628 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#1: ffff88807b471628 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
#2: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:4654 [inline]
#2: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim mm/page_alloc.c:4678 [inline]
#2: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath+0x1017/0x2700 mm/page_alloc.c:5128
3 locks held by syz-executor/8342:
#0: ffff88814c8f8458 (&xt[i].mutex){+.+.}-{3:3}, at: xt_find_table_lock+0x5e/0x360 net/netfilter/x_tables.c:1265
#1: ffff88807eb6c028 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#1: ffff88807eb6c028 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
#2: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:4654 [inline]
#2: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim mm/page_alloc.c:4678 [inline]
#2: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath+0x1017/0x2700 mm/page_alloc.c:5128
2 locks held by syz-executor/12456:
#0: ffff88807b475c28 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88807b475c28 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:4654 [inline]
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim mm/page_alloc.c:4678 [inline]
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath+0x1017/0x2700 mm/page_alloc.c:5128
2 locks held by syz-executor/15315:
#0: ffff88807e4dc728 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88807e4dc728 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:4654 [inline]
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim mm/page_alloc.c:4678 [inline]
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath+0x1017/0x2700 mm/page_alloc.c:5128
3 locks held by syz.9.2969/16495:
#0: ffff888147831448 (&q->debugfs_mutex){+.+.}-{3:3}, at: blk_trace_ioctl+0x144/0x5a0 kernel/trace/blktrace.c:735
#1: ffffffff8c35d628 (
relay_channels_mutex
){+.+.}-{3:3}
, at: relay_open+0x31a/0x8e0 kernel/relay.c:518
#2:
ffff8880b913a358 (&rq->__lock){-.-.}-{2:2}
, at: raw_spin_rq_lock_nested+0x25/0x130 kernel/sched/core.c:475
2 locks held by syz-executor/16977:
3 locks held by kworker/1:20/18721:
#0: ffff888016c70938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
#1: ffffc90002eefd00 ((work_completion)(&(&vi->refill)->work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
#2: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:4654 [inline]
#2: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim mm/page_alloc.c:4678 [inline]
#2: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath+0x1017/0x2700 mm/page_alloc.c:5128
2 locks held by kworker/0:14/20266:
#0: ffff888016c72138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
#1: ffffc900043ffd00 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
3 locks held by kworker/0:15/20267:
#0: ffff888016c70938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
#1: ffffc9000440fd00 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
#2: ffff888074c26400 (&nsim_dev->port_list_lock){+.+.}-{3:3}, at: nsim_dev_trap_report_work+0x56/0xab0 drivers/net/netdevsim/dev.c:757
=============================================
NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/25/2026
Call Trace:
<TASK>
dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
watchdog+0xe1b/0xe60 kernel/hung_task.c:369
kthread+0x42e/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
</TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 8342 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/25/2026
RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:157 [inline]
RIP: 0010:unwind_next_frame+0x15c/0x1cf0 arch/x86/kernel/unwind_orc.c:448
Code: 8b 36 49 83 f7 01 49 c7 c4 80 99 28 8a 4d 29 fe 0f 84 74 02 00 00 49 81 fe 00 00 00 81 0f 92 c0 49 81 fe 04 7f 00 8a 0f 93 c1 <08> c1 0f 85 d5 00 00 00 48 c7 c0 00 00 00 81 4c 89 f5 48 29 c5 48
RSP: 0018:ffffc9000344f430 EFLAGS: 00000287
RAX: 1ffff92000689e00 RBX: ffffc9000344f4c8 RCX: ffffffff962eff00
RDX: dffffc0000000000 RSI: ffffffff8148b38c RDI: ffffffff81350ed7
RBP: 1ffff92000689ea0 R08: ffffc9000344f590 R09: 0000000000000007
R10: dffffc0000000000 R11: fffff52000689ea5 R12: ffffffff8a289980
R13: ffffc9000344fb88 R14: ffffffff8148b38b R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000563ffc8def20 CR3: 000000001b5f3000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
arch_stack_walk+0x10c/0x140 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xa6/0xf0 kernel/stacktrace.c:122
save_stack+0x121/0x230 mm/page_owner.c:119
__reset_page_owner+0x51/0x180 mm/page_owner.c:140
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1340 [inline]
free_pcp_prepare mm/page_alloc.c:1391 [inline]
free_unref_page_prepare+0x637/0x6c0 mm/page_alloc.c:3317
free_unref_page+0x8f/0x2a0 mm/page_alloc.c:3396
__vunmap+0x8e0/0xa80 mm/vmalloc.c:2628
kcov_put kernel/kcov.c:417 [inline]
kcov_close+0x27/0x50 kernel/kcov.c:519
__fput+0x212/0x8c0 fs/file_table.c:311
task_work_run+0x125/0x1a0 kernel/task_work.c:188
exit_task_work include/linux/task_work.h:33 [inline]
do_exit+0x635/0x2110 kernel/exit.c:884
do_group_exit+0x12c/0x2f0 kernel/exit.c:998
get_signal+0x7eb/0x12e0 kernel/signal.c:2901
arch_do_signal_or_restart+0xe6/0x12a0 arch/x86/kernel/signal.c:867
handle_signal_work kernel/entry/common.c:154 [inline]
exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
__syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fed05cc066a
Code: Unable to access opcode bytes at RIP 0x7fed05cc0640.
RSP: 002b:00007fff79fbb5a8 EFLAGS: 00000212 ORIG_RAX: 0000000000000037
RAX: fffffffffffffff2 RBX: 0000000000000003 RCX: 00007fed05cc066a
RDX: 0000000000000061 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007fff79fbb610 R08: 00007fff79fbb5bc R09: 0000000000000000
R10: 00007fff79fbb610 R11: 0000000000000212 R12: 00007fff79fbb5bc
R13: 00007fed05d558fd R14: 0000000000129219 R15: 00007fff79fbbd00
</TASK>
---
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 syzk...@googlegroups.com.
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If the report is already addressed, let syzbot know by replying with:
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If you want to overwrite report's subsystems, reply with:
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If the report is a duplicate of another one, reply with:
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If you want to undo deduplication, reply with:
#syz undup
syzbot found the following issue on:
HEAD commit: c86c4726e7f0 Linux 5.15.211
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=17d57789580000
kernel config: https://syzkaller.appspot.com/x/.config?x=6f8e2266b61925dc
dashboard link: https://syzkaller.appspot.com/bug?extid=50b2c1e0c613accaa3b9
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c3e980557785/disk-c86c4726.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/5fbaf3714ad0/vmlinux-c86c4726.xz
kernel image: https://storage.googleapis.com/syzbot-assets/de60a4f1e940/bzImage-c86c4726.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+50b2c1...@syzkaller.appspotmail.com
INFO: task kworker/u4:8:4293 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:8 state:D stack:18592 pid: 4293 ppid: 2 flags:0x00004000
Workqueue: netns cleanup_net
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11c3/0x4350 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
__mutex_lock_common+0xdf5/0x2400 kernel/locking/mutex.c:669
__mutex_lock kernel/locking/mutex.c:729 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
xt_find_table+0x43/0xc0 net/netfilter/x_tables.c:1244
arpt_unregister_table_pre_exit+0x20/0xb0 net/ipv4/netfilter/arp_tables.c:1582
ops_pre_exit_list net/core/net_namespace.c:162 [inline]
cleanup_net+0x58e/0xba0 net/core/net_namespace.c:615
process_one_work+0x867/0xff0 kernel/workqueue.c:2310
worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
kthread+0x42e/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
</TASK>
Showing all locks held in the system:
2 locks held by init/1:
#0: ffff88802c2a7128 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88802c2a7128 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:4654 [inline]
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim mm/page_alloc.c:4678 [inline]
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath+0x1017/0x2700 mm/page_alloc.c:5128
1 lock held by khungtaskd/27:
#0: ffffffff8c31ef20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
3 locks held by kswapd1/255:
2 locks held by klogd/3549:
2 locks held by udevd/3560:
#0: ffff88807eb6e328 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88807eb6e328 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:4654 [inline]
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim mm/page_alloc.c:4678 [inline]
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath+0x1017/0x2700 mm/page_alloc.c:5128
2 locks held by dhcpcd/3852:
#0: ffff88801e9f1d28 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88801e9f1d28 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:4654 [inline]
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim mm/page_alloc.c:4678 [inline]
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath+0x1017/0x2700 mm/page_alloc.c:5128
2 locks held by crond/3927:
#0: ffff88801eeb8128 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88801eeb8128 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:4654 [inline]
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim mm/page_alloc.c:4678 [inline]
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath+0x1017/0x2700 mm/page_alloc.c:5128
2 locks held by getty/3945:
#0: ffff88814cd3b098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
#1: ffffc90002cf62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x594/0x1a50 drivers/tty/n_tty.c:2158
2 locks held by sshd-session/4174:
2 locks held by syz-executor/4175:
#0: ffff88807b475528 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88807b475528 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:4654 [inline]
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim mm/page_alloc.c:4678 [inline]
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath+0x1017/0x2700 mm/page_alloc.c:5128
4 locks held by kworker/u4:8/4293:
#0: ffff888016dcd938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
#1: ffffc9000329fd00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
#2: ffffffff8d43f210 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x148/0xba0 net/core/net_namespace.c:589
#3: ffff88814c8f8458 (&xt[i].mutex){+.+.}-{3:3}, at: xt_find_table+0x43/0xc0 net/netfilter/x_tables.c:1244
3 locks held by udevd/4319:
#0: ffff88807c49ed48 (&tsk->futex_exit_mutex){+.+.}-{3:3}, at: futex_cleanup_begin kernel/futex/core.c:3894 [inline]
#0: ffff88807c49ed48 (&tsk->futex_exit_mutex){+.+.}-{3:3}, at: futex_exit_release+0x2f/0x1c0 kernel/futex/core.c:3946
#1: ffff88807b471628 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#1: ffff88807b471628 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
#2: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:4654 [inline]
#2: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim mm/page_alloc.c:4678 [inline]
#2: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath+0x1017/0x2700 mm/page_alloc.c:5128
3 locks held by syz-executor/8342:
#0: ffff88814c8f8458 (&xt[i].mutex){+.+.}-{3:3}, at: xt_find_table_lock+0x5e/0x360 net/netfilter/x_tables.c:1265
#1: ffff88807eb6c028 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#1: ffff88807eb6c028 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
#2: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:4654 [inline]
#2: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim mm/page_alloc.c:4678 [inline]
#2: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath+0x1017/0x2700 mm/page_alloc.c:5128
2 locks held by syz-executor/12456:
#0: ffff88807b475c28 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88807b475c28 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:4654 [inline]
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim mm/page_alloc.c:4678 [inline]
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath+0x1017/0x2700 mm/page_alloc.c:5128
2 locks held by syz-executor/15315:
#0: ffff88807e4dc728 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88807e4dc728 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:4654 [inline]
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim mm/page_alloc.c:4678 [inline]
#1: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath+0x1017/0x2700 mm/page_alloc.c:5128
3 locks held by syz.9.2969/16495:
#0: ffff888147831448 (&q->debugfs_mutex){+.+.}-{3:3}, at: blk_trace_ioctl+0x144/0x5a0 kernel/trace/blktrace.c:735
#1: ffffffff8c35d628 (
relay_channels_mutex
){+.+.}-{3:3}
, at: relay_open+0x31a/0x8e0 kernel/relay.c:518
#2:
ffff8880b913a358 (&rq->__lock){-.-.}-{2:2}
, at: raw_spin_rq_lock_nested+0x25/0x130 kernel/sched/core.c:475
2 locks held by syz-executor/16977:
3 locks held by kworker/1:20/18721:
#0: ffff888016c70938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
#1: ffffc90002eefd00 ((work_completion)(&(&vi->refill)->work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
#2: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:4654 [inline]
#2: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim mm/page_alloc.c:4678 [inline]
#2: ffffffff8c3debc0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath+0x1017/0x2700 mm/page_alloc.c:5128
2 locks held by kworker/0:14/20266:
#0: ffff888016c72138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
#1: ffffc900043ffd00 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
3 locks held by kworker/0:15/20267:
#0: ffff888016c70938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
#1: ffffc9000440fd00 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
#2: ffff888074c26400 (&nsim_dev->port_list_lock){+.+.}-{3:3}, at: nsim_dev_trap_report_work+0x56/0xab0 drivers/net/netdevsim/dev.c:757
=============================================
NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/25/2026
Call Trace:
<TASK>
dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
watchdog+0xe1b/0xe60 kernel/hung_task.c:369
kthread+0x42e/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
</TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 8342 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/25/2026
RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:157 [inline]
RIP: 0010:unwind_next_frame+0x15c/0x1cf0 arch/x86/kernel/unwind_orc.c:448
Code: 8b 36 49 83 f7 01 49 c7 c4 80 99 28 8a 4d 29 fe 0f 84 74 02 00 00 49 81 fe 00 00 00 81 0f 92 c0 49 81 fe 04 7f 00 8a 0f 93 c1 <08> c1 0f 85 d5 00 00 00 48 c7 c0 00 00 00 81 4c 89 f5 48 29 c5 48
RSP: 0018:ffffc9000344f430 EFLAGS: 00000287
RAX: 1ffff92000689e00 RBX: ffffc9000344f4c8 RCX: ffffffff962eff00
RDX: dffffc0000000000 RSI: ffffffff8148b38c RDI: ffffffff81350ed7
RBP: 1ffff92000689ea0 R08: ffffc9000344f590 R09: 0000000000000007
R10: dffffc0000000000 R11: fffff52000689ea5 R12: ffffffff8a289980
R13: ffffc9000344fb88 R14: ffffffff8148b38b R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000563ffc8def20 CR3: 000000001b5f3000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
arch_stack_walk+0x10c/0x140 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xa6/0xf0 kernel/stacktrace.c:122
save_stack+0x121/0x230 mm/page_owner.c:119
__reset_page_owner+0x51/0x180 mm/page_owner.c:140
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1340 [inline]
free_pcp_prepare mm/page_alloc.c:1391 [inline]
free_unref_page_prepare+0x637/0x6c0 mm/page_alloc.c:3317
free_unref_page+0x8f/0x2a0 mm/page_alloc.c:3396
__vunmap+0x8e0/0xa80 mm/vmalloc.c:2628
kcov_put kernel/kcov.c:417 [inline]
kcov_close+0x27/0x50 kernel/kcov.c:519
__fput+0x212/0x8c0 fs/file_table.c:311
task_work_run+0x125/0x1a0 kernel/task_work.c:188
exit_task_work include/linux/task_work.h:33 [inline]
do_exit+0x635/0x2110 kernel/exit.c:884
do_group_exit+0x12c/0x2f0 kernel/exit.c:998
get_signal+0x7eb/0x12e0 kernel/signal.c:2901
arch_do_signal_or_restart+0xe6/0x12a0 arch/x86/kernel/signal.c:867
handle_signal_work kernel/entry/common.c:154 [inline]
exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
__syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fed05cc066a
Code: Unable to access opcode bytes at RIP 0x7fed05cc0640.
RSP: 002b:00007fff79fbb5a8 EFLAGS: 00000212 ORIG_RAX: 0000000000000037
RAX: fffffffffffffff2 RBX: 0000000000000003 RCX: 00007fed05cc066a
RDX: 0000000000000061 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007fff79fbb610 R08: 00007fff79fbb5bc R09: 0000000000000000
R10: 00007fff79fbb610 R11: 0000000000000212 R12: 00007fff79fbb5bc
R13: 00007fed05d558fd R14: 0000000000129219 R15: 00007fff79fbbd00
</TASK>
---
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