syzbot


INFO: task hung in do_arpt_get_ctl (2)

Status: upstream: reported syz repro on 2024/10/20 17:31
Subsystems: netfilter
[Documentation on labels]
Reported-by: syzbot+47dcc37219cf4421eec6@syzkaller.appspotmail.com
First crash: 612d, last: 612d
✨ AI Jobs (5)
ID Workflow Result Correct Bug Created Started Finished Revision Error
557fe43f-e914-4fd9-852f-1a0e658067cb assessment-security 💥 INFO: task hung in do_arpt_get_ctl (2) 2026/06/18 04:46 2026/06/18 04:46 2026/06/18 05:15 b62b3ded1759f79b37600c5ffe2b0a81b919b0b0
failed to run ["make" "KERNELVERSION=syzkaller" "KERNELRELEASE=syzkaller" "LOCALVERSION=-syzkaller" "-j" "32" "ARCH=x86_64" "CC=ccache clang" "LD=ld.lld" "O=/app/workdir/cache/build/2eb48da40994236ce2...
truncated to first 200 bytes; open job for full error
d5751aaa-de1d-42ed-9888-1408e56b2c8f assessment-security 💥 INFO: task hung in do_arpt_get_ctl (2) 2026/06/10 00:45 2026/06/10 00:45 2026/06/10 01:07 c36c07f6c1f2230a36374cbd22235f635e8f9284
failed to run ["make" "KERNELVERSION=syzkaller" "KERNELRELEASE=syzkaller" "LOCALVERSION=-syzkaller" "-j" "32" "ARCH=x86_64" "CC=ccache clang" "LD=ld.lld" "O=/app/workdir/cache/build/2eb48da40994236ce2...
truncated to first 200 bytes; open job for full error
f869afb9-b052-416a-9759-f8df5fc39a4b assessment-security 💥 INFO: task hung in do_arpt_get_ctl (2) 2026/06/04 02:50 2026/06/04 02:50 2026/06/04 03:04 62fe15281f5011cd203d8845b8767b10e7443aa5
failed to run ["make" "KERNELVERSION=syzkaller" "KERNELRELEASE=syzkaller" "LOCALVERSION=-syzkaller" "-j" "32" "ARCH=x86_64" "CC=ccache clang" "LD=ld.lld" "O=/app/workdir/cache/build/2eb48da40994236ce2...
truncated to first 200 bytes; open job for full error
0a412361-9cfb-4fae-bc90-cba4490f2dfa assessment-security 💥 INFO: task hung in do_arpt_get_ctl (2) 2026/06/01 17:48 2026/06/01 17:48 2026/06/01 18:17 386cc6dacdf7e3ebce9507beed6755d7e999554d
failed to run ["make" "KERNELVERSION=syzkaller" "KERNELRELEASE=syzkaller" "LOCALVERSION=-syzkaller" "-j" "32" "ARCH=x86_64" "CC=ccache clang" "LD=ld.lld" "O=/app/workdir/cache/build/2eb48da40994236ce2...
truncated to first 200 bytes; open job for full error
e4bf9ac1-7500-4393-9bc5-7c6a8393b437 assessment-security 💥 INFO: task hung in do_arpt_get_ctl (2) 2026/05/17 06:24 2026/05/17 06:24 2026/05/17 06:53 de5aae85e5f28e2fa1c7deefcc24fe286abe5140
failed to run ["make" "KERNELVERSION=syzkaller" "KERNELRELEASE=syzkaller" "LOCALVERSION=-syzkaller" "-j" "32" "ARCH=x86_64" "CC=ccache clang" "LD=ld.lld" "O=/app/workdir/cache/build/2eb48da40994236ce2...
truncated to first 200 bytes; open job for full error
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [netfilter?] INFO: task hung in do_arpt_get_ctl (2) 0 (1) 2024/10/20 17:31
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in do_arpt_get_ctl netfilter 1 1 1982d 1982d 0/29 auto-closed as invalid on 2021/04/16 01:34
Last patch testing requests (9)
Created Duration User Patch Repo Result
2026/05/14 01:26 21m retest repro upstream error
2026/03/04 23:41 22m retest repro upstream log
2025/12/24 23:03 20m retest repro upstream log
2025/10/15 22:07 20m retest repro upstream log
2025/08/06 21:15 20m retest repro upstream log
2025/05/28 20:06 20m retest repro upstream log
2025/03/19 18:39 21m retest repro upstream log
2025/01/08 17:51 13m retest repro upstream report log
2024/10/30 17:27 18m retest repro upstream log

Sample crash report:
INFO: task syz-executor:5236 blocked for more than 143 seconds.
      Not tainted 6.12.0-rc3-syzkaller-00044-g2f87d0916ce0 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:20608 pid:5236  tgid:5236  ppid:5230   flags:0x00000000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5322 [inline]
 __schedule+0x1895/0x4b30 kernel/sched/core.c:6682
 __schedule_loop kernel/sched/core.c:6759 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6774
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6831
 __mutex_lock_common kernel/locking/mutex.c:684 [inline]
 __mutex_lock+0x6a7/0xd70 kernel/locking/mutex.c:752
 xt_find_table_lock+0x4c/0x3b0 net/netfilter/x_tables.c:1243
 xt_request_find_table_lock+0x26/0x100 net/netfilter/x_tables.c:1285
 get_info net/ipv4/netfilter/arp_tables.c:808 [inline]
 do_arpt_get_ctl+0x904/0x16b0 net/ipv4/netfilter/arp_tables.c:1452
 nf_getsockopt+0x299/0x2c0 net/netfilter/nf_sockopt.c:116
 ip_getsockopt+0x222/0x2e0 net/ipv4/ip_sockglue.c:1777
 tcp_getsockopt+0x163/0x1c0 net/ipv4/tcp.c:4670
 do_sock_getsockopt+0x3c4/0x7e0 net/socket.c:2396
 __sys_getsockopt+0x267/0x330 net/socket.c:2425
 __do_sys_getsockopt net/socket.c:2435 [inline]
 __se_sys_getsockopt net/socket.c:2432 [inline]
 __x64_sys_getsockopt+0xb5/0xd0 net/socket.c:2432
 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: 0033:0x7f766ed7fd3a
RSP: 002b:00007ffc9412c6b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000037
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f766ed7fd3a
RDX: 0000000000000060 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007ffc9412c6d0 R08: 00007ffc9412c6cc R09: 00007ffc9412cab7
R10: 00007ffc9412c6d0 R11: 0000000000000246 R12: 00007ffc9412c6cc
R13: 00000000000481ce R14: 00000000000481a7 R15: 00007ffc9412cdf0
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/25:
 #0: ffffffff8e937de0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 #0: ffffffff8e937de0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8e937de0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6720
1 lock held by kswapd0/79:
1 lock held by klogd/4585:
 #0: ffffffff8ea37160 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:3907 [inline]
 #0: ffffffff8ea37160 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim+0xd4/0x3c0 mm/page_alloc.c:3932
1 lock held by dhcpcd/4810:
 #0: ffffffff8ea37160 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:3907 [inline]
 #0: ffffffff8ea37160 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim+0xd4/0x3c0 mm/page_alloc.c:3932
2 locks held by getty/4897:
 #0: ffff88801ebb90a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000039b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6a6/0x1e00 drivers/tty/n_tty.c:2211
2 locks held by syz-execprog/5134:
 #0: ffff88803e1ae8a8 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_invalidate_lock_shared include/linux/fs.h:870 [inline]
 #0: ffff88803e1ae8a8 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_fault+0xd54/0x1950 mm/filemap.c:3350
 #1: ffffffff8ea37160 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:3907 [inline]
 #1: ffffffff8ea37160 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim+0xd4/0x3c0 mm/page_alloc.c:3932
1 lock held by syz-executor/5126:
 #0: ffffffff8ea37160 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:3907 [inline]
 #0: ffffffff8ea37160 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim+0xd4/0x3c0 mm/page_alloc.c:3932
2 locks held by syz-executor/5231:
 #0: ffff8880006f29b8 (&vma->vm_lock->lock){++++}-{3:3}, at: vma_start_read include/linux/mm.h:704 [inline]
 #0: ffff8880006f29b8 (&vma->vm_lock->lock){++++}-{3:3}, at: lock_vma_under_rcu+0x34b/0x790 mm/memory.c:6228
 #1: ffffffff8ea37160 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:3907 [inline]
 #1: ffffffff8ea37160 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim+0xd4/0x3c0 mm/page_alloc.c:3932
1 lock held by syz-executor/5232:
 #0: ffff88801bba2458 (&xt[i].mutex){+.+.}-{3:3}, at: xt_find_table_lock+0x4c/0x3b0 net/netfilter/x_tables.c:1243
2 locks held by syz-executor/5233:
 #0: ffff88801198f220 (&vma->vm_lock->lock){++++}-{3:3}, at: vma_start_read include/linux/mm.h:704 [inline]
 #0: ffff88801198f220 (&vma->vm_lock->lock){++++}-{3:3}, at: lock_vma_under_rcu+0x34b/0x790 mm/memory.c:6228
 #1: ffffffff8ea37160 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:3907 [inline]
 #1: ffffffff8ea37160 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim+0xd4/0x3c0 mm/page_alloc.c:3932
2 locks held by syz-executor/5234:
 #0: ffff88801bba2458 (&xt[i].mutex){+.+.}-{3:3}, at: xt_find_table_lock+0x4c/0x3b0 net/netfilter/x_tables.c:1243
 #1: ffffffff8ea37160 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:3907 [inline]
 #1: ffffffff8ea37160 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim+0xd4/0x3c0 mm/page_alloc.c:3932
2 locks held by syz-executor/5235:
 #0: ffff88803c3ac808 (&vma->vm_lock->lock){++++}-{3:3}, at: vma_start_read include/linux/mm.h:704 [inline]
 #0: ffff88803c3ac808 (&vma->vm_lock->lock){++++}-{3:3}, at: lock_vma_under_rcu+0x34b/0x790 mm/memory.c:6228
 #1: ffffffff8ea37160 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:3907 [inline]
 #1: ffffffff8ea37160 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim+0xd4/0x3c0 mm/page_alloc.c:3932
1 lock held by syz-executor/5236:
 #0: ffff88801bba2458 (&xt[i].mutex){+.+.}-{3:3}, at: xt_find_table_lock+0x4c/0x3b0 net/netfilter/x_tables.c:1243

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 25 Comm: khungtaskd Not tainted 6.12.0-rc3-syzkaller-00044-g2f87d0916ce0 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x49c/0x4d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x198/0x320 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:223 [inline]
 watchdog+0xff4/0x1040 kernel/hung_task.c:379
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/10/16 17:27 upstream 2f87d0916ce0 bde2d81c .config console log report syz / log [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root INFO: task hung in do_arpt_get_ctl
* Struck through repros no longer work on HEAD.