[v6.1] INFO: task hung in mpol_rebind_mm (2)
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syzbot
Sep 23, 2025, 3:26:26 AMSep 23
to syzkaller...@googlegroups.com
Hello,
syzbot found the following issue on:
HEAD commit: 363a599da6d9 Linux 6.1.153
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=17d93534580000
kernel config: https://syzkaller.appspot.com/x/.config?x=7eb38bd5021fec61
dashboard link: https://syzkaller.appspot.com/bug?extid=b9b07367c7593c3811f2
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=171904e2580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/7cf87f25c694/disk-363a599d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ec86135ba3cc/vmlinux-363a599d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/117cec1ae5fa/bzImage-363a599d.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b9b073...@syzkaller.appspotmail.com
INFO: task syz-executor:4411 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor state:D stack:21512 pid:4411 ppid:4405 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
schedule+0xb9/0x180 kernel/sched/core.c:6637
rwsem_down_write_slowpath+0xbed/0x1090 kernel/locking/rwsem.c:1189
mmap_write_lock include/linux/mmap_lock.h:71 [inline]
mpol_rebind_mm+0xbe/0x370 mm/mempolicy.c:386
cpuset_attach+0x284/0x540 kernel/cgroup/cpuset.c:2663
cgroup_migrate_execute+0x7a3/0xf30 kernel/cgroup/cgroup.c:2639
cgroup_attach_task+0x558/0x840 kernel/cgroup/cgroup.c:2930
__cgroup1_procs_write+0x2e0/0x3e0 kernel/cgroup/cgroup-v1.c:522
cgroup_file_write+0x2f8/0x660 kernel/cgroup/cgroup.c:4077
kernfs_fop_write_iter+0x3b2/0x520 fs/kernfs/file.c:352
call_write_iter include/linux/fs.h:2265 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x44c/0x960 fs/read_write.c:584
ksys_write+0x143/0x240 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f00c958d97f
RSP: 002b:00007fff91925a20 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f00c958d97f
RDX: 0000000000000001 RSI: 00007fff91925a70 RDI: 0000000000000003
RBP: 00007fff91925fe0 R08: 0000000000000000 R09: 00007fff91925877
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001
R13: 00007fff91925a70 R14: 00007fff91925fa0 R15: 00007fff91925fe0
</TASK>
INFO: task syz.0.25:4536 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.25 state:D stack:25320 pid:4536 ppid:4397 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
schedule+0xb9/0x180 kernel/sched/core.c:6637
rwsem_down_write_slowpath+0xbed/0x1090 kernel/locking/rwsem.c:1189
mmap_write_lock include/linux/mmap_lock.h:71 [inline]
exit_mmap+0x20f/0x8e0 mm/mmap.c:3258
__mmput+0x118/0x3c0 kernel/fork.c:1200
exit_mm+0x1e6/0x2c0 kernel/exit.c:565
do_exit+0x8c1/0x2400 kernel/exit.c:867
do_group_exit+0x217/0x2d0 kernel/exit.c:1022
__do_sys_exit_group kernel/exit.c:1033 [inline]
__se_sys_exit_group kernel/exit.c:1031 [inline]
__x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1031
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f438418eec9
RSP: 002b:00007ffce149e568 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f438418eec9
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffce149e5cc R08: 00000005e149e65f R09: 00000000000927c0
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000002
R13: 00000000000927c0 R14: 0000000000025183 R15: 00007ffce149e620
</TASK>
INFO: task syz.1.18:4537 blocked for more than 144 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.18 state:D stack:25728 pid:4537 ppid:4404 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
schedule+0xb9/0x180 kernel/sched/core.c:6637
rwsem_down_write_slowpath+0xbed/0x1090 kernel/locking/rwsem.c:1189
mmap_write_lock include/linux/mmap_lock.h:71 [inline]
exit_mmap+0x20f/0x8e0 mm/mmap.c:3258
__mmput+0x118/0x3c0 kernel/fork.c:1200
exit_mm+0x1e6/0x2c0 kernel/exit.c:565
do_exit+0x8c1/0x2400 kernel/exit.c:867
do_group_exit+0x217/0x2d0 kernel/exit.c:1022
__do_sys_exit_group kernel/exit.c:1033 [inline]
__se_sys_exit_group kernel/exit.c:1031 [inline]
__x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1031
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fdf37f8eec9
RSP: 002b:00007ffc504dafe8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fdf37f8eec9
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000003 R08: 00000005504db0df R09: 00007fdf381b1280
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fdf381b1280 R14: 0000000000000003 R15: 00007ffc504db0a0
</TASK>
Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
#0: ffffffff8cb2b570 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
#0: ffffffff8cb2bd90 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
#0: ffffffff8cb2abe0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#0: ffffffff8cb2abe0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#0: ffffffff8cb2abe0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513
1 lock held by dhcpcd/3932:
#0: ffffffff8cb53810 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: copy_process+0x248b/0x4020 kernel/fork.c:2446
2 locks held by getty/4030:
#0: ffff88802fa51098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
#1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41b/0x1380 drivers/tty/n_tty.c:2198
1 lock held by udevd/4311:
#0: ffff88807cd81f58 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
#0: ffff88807cd81f58 (&mm->mmap_lock){++++}-{3:3}, at: __vm_munmap+0x141/0x290 mm/mmap.c:2933
2 locks held by kworker/0:4/4318:
1 lock held by syz-executor/4393:
#0: ffffffff8cb53810 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: do_exit+0x578/0x2400 kernel/exit.c:827
2 locks held by syz-executor/4402:
#0: ffffffff8cbc4e50 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mmap kernel/fork.c:593 [inline]
#0: ffffffff8cbc4e50 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1541 [inline]
#0: ffffffff8cbc4e50 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm+0x2a9/0x15c0 kernel/fork.c:1590
#1: ffff88802866f958 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
#1: ffff88802866f958 (&mm->mmap_lock){++++}-{3:3}, at: dup_mmap kernel/fork.c:594 [inline]
#1: ffff88802866f958 (&mm->mmap_lock){++++}-{3:3}, at: dup_mm kernel/fork.c:1541 [inline]
#1: ffff88802866f958 (&mm->mmap_lock){++++}-{3:3}, at: copy_mm+0x2c3/0x15c0 kernel/fork.c:1590
1 lock held by udevd/4410:
#0: ffff88807297bd58 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
#0: ffff88807297bd58 (&mm->mmap_lock){++++}-{3:3}, at: __vm_munmap+0x141/0x290 mm/mmap.c:2933
7 locks held by syz-executor/4411:
#0: ffff888023ff0460 (sb_writers#11){.+.+}-{0:0}, at: vfs_write+0x256/0x960 fs/read_write.c:580
#1: ffff8880606d4888 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1e3/0x520 fs/kernfs/file.c:343
#2: ffffffff8cb53628 (cgroup_mutex){+.+.}-{3:3}, at: cgroup_lock include/linux/cgroup.h:442 [inline]
#2: ffffffff8cb53628 (cgroup_mutex){+.+.}-{3:3}, at: cgroup_kn_lock_live+0xee/0x230 kernel/cgroup/cgroup.c:1677
#3: ffffffff8c9c7a70 (cpu_hotplug_lock){++++}-{0:0}, at: cgroup_attach_lock kernel/cgroup/cgroup.c:2453 [inline]
#3: ffffffff8c9c7a70 (cpu_hotplug_lock){++++}-{0:0}, at: cgroup_procs_write_start+0x183/0x600 kernel/cgroup/cgroup.c:2959
#4: ffffffff8cb53810 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: cgroup_attach_lock kernel/cgroup/cgroup.c:2455 [inline]
#4: ffffffff8cb53810 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: cgroup_procs_write_start+0x199/0x600 kernel/cgroup/cgroup.c:2959
#5: ffffffff8cb61ba8 (cpuset_mutex){+.+.}-{3:3}, at: cpuset_attach+0xac/0x540 kernel/cgroup/cpuset.c:2647
#6: ffff88807297cc58 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock include/linux/mmap_lock.h:71 [inline]
#6: ffff88807297cc58 (&mm->mmap_lock){++++}-{3:3}, at: mpol_rebind_mm+0xbe/0x370 mm/mempolicy.c:386
2 locks held by kworker/u4:9/4532:
#0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#1: ffffc90003ec7d00 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
1 lock held by modprobe/4535:
#0: ffff88807470f1d8 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
#0: ffff88807470f1d8 (&mm->mmap_lock){++++}-{3:3}, at: vm_mmap_pgoff+0x15d/0x2b0 mm/util.c:518
1 lock held by syz.0.25/4536:
#0: ffff88807470f958 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock include/linux/mmap_lock.h:71 [inline]
#0: ffff88807470f958 (&mm->mmap_lock){++++}-{3:3}, at: exit_mmap+0x20f/0x8e0 mm/mmap.c:3258
1 lock held by syz.1.18/4537:
#0: ffff88801fe4ea58 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock include/linux/mmap_lock.h:71 [inline]
#0: ffff88801fe4ea58 (&mm->mmap_lock){++++}-{3:3}, at: exit_mmap+0x20f/0x8e0 mm/mmap.c:3258
=============================================
NMI backtrace for cpu 1
CPU: 1 PID: 28 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
<TASK>
dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
nmi_cpu_backtrace+0x3f4/0x470 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
watchdog+0xeee/0xf30 kernel/hung_task.c:377
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4334 Comm: kworker/u4:5 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Workqueue: bat_events batadv_nc_worker
RIP: 0010:instrument_atomic_read include/linux/instrumented.h:72 [inline]
RIP: 0010:_test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
RIP: 0010:hlock_class kernel/locking/lockdep.c:228 [inline]
RIP: 0010:__lock_acquire+0x10ad/0x7c50 kernel/locking/lockdep.c:5045
Code: 0f b6 04 00 84 c0 0f 85 68 5d 00 00 8b 03 89 c3 81 e3 ff 1f 00 00 c1 e8 03 25 f8 03 00 00 48 8d b8 40 22 ae 90 be 08 00 00 00 <e8> de e9 6d 00 48 0f a3 1d 56 1a 4b 0f 0f 83 8c 01 00 00 48 8d 04
RSP: 0018:ffffc90003e87780 EFLAGS: 00000006
RAX: 00000000000000e8 RBX: 0000000000000765 RCX: 00000000d85187a2
RDX: 0000000093ddaba0 RSI: 0000000000000008 RDI: ffffffff90ae2328
RBP: ffffc90003e879d0 R08: dffffc0000000000 R09: fffffbfff215c466
R10: fffffbfff215c466 R11: 1ffffffff215c465 R12: 00000000ab5163cb
R13: 000000007ad1ed9a R14: 000000002453d227 R15: ffff88801c73e410
FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2b99af1cd8 CR3: 000000002f730000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
_raw_spin_lock_bh+0x32/0x50 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:356 [inline]
batadv_nc_purge_paths+0xe7/0x3b0 net/batman-adv/network-coding.c:442
batadv_nc_worker+0x365/0x600 net/batman-adv/network-coding.c:722
process_one_work+0x898/0x1160 kernel/workqueue.c:2292
worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</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.
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
syzbot found the following issue on:
HEAD commit: 363a599da6d9 Linux 6.1.153
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=17d93534580000
kernel config: https://syzkaller.appspot.com/x/.config?x=7eb38bd5021fec61
dashboard link: https://syzkaller.appspot.com/bug?extid=b9b07367c7593c3811f2
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=171904e2580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/7cf87f25c694/disk-363a599d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ec86135ba3cc/vmlinux-363a599d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/117cec1ae5fa/bzImage-363a599d.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b9b073...@syzkaller.appspotmail.com
INFO: task syz-executor:4411 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor state:D stack:21512 pid:4411 ppid:4405 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
schedule+0xb9/0x180 kernel/sched/core.c:6637
rwsem_down_write_slowpath+0xbed/0x1090 kernel/locking/rwsem.c:1189
mmap_write_lock include/linux/mmap_lock.h:71 [inline]
mpol_rebind_mm+0xbe/0x370 mm/mempolicy.c:386
cpuset_attach+0x284/0x540 kernel/cgroup/cpuset.c:2663
cgroup_migrate_execute+0x7a3/0xf30 kernel/cgroup/cgroup.c:2639
cgroup_attach_task+0x558/0x840 kernel/cgroup/cgroup.c:2930
__cgroup1_procs_write+0x2e0/0x3e0 kernel/cgroup/cgroup-v1.c:522
cgroup_file_write+0x2f8/0x660 kernel/cgroup/cgroup.c:4077
kernfs_fop_write_iter+0x3b2/0x520 fs/kernfs/file.c:352
call_write_iter include/linux/fs.h:2265 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x44c/0x960 fs/read_write.c:584
ksys_write+0x143/0x240 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f00c958d97f
RSP: 002b:00007fff91925a20 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f00c958d97f
RDX: 0000000000000001 RSI: 00007fff91925a70 RDI: 0000000000000003
RBP: 00007fff91925fe0 R08: 0000000000000000 R09: 00007fff91925877
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001
R13: 00007fff91925a70 R14: 00007fff91925fa0 R15: 00007fff91925fe0
</TASK>
INFO: task syz.0.25:4536 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.25 state:D stack:25320 pid:4536 ppid:4397 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
schedule+0xb9/0x180 kernel/sched/core.c:6637
rwsem_down_write_slowpath+0xbed/0x1090 kernel/locking/rwsem.c:1189
mmap_write_lock include/linux/mmap_lock.h:71 [inline]
exit_mmap+0x20f/0x8e0 mm/mmap.c:3258
__mmput+0x118/0x3c0 kernel/fork.c:1200
exit_mm+0x1e6/0x2c0 kernel/exit.c:565
do_exit+0x8c1/0x2400 kernel/exit.c:867
do_group_exit+0x217/0x2d0 kernel/exit.c:1022
__do_sys_exit_group kernel/exit.c:1033 [inline]
__se_sys_exit_group kernel/exit.c:1031 [inline]
__x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1031
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f438418eec9
RSP: 002b:00007ffce149e568 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f438418eec9
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffce149e5cc R08: 00000005e149e65f R09: 00000000000927c0
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000002
R13: 00000000000927c0 R14: 0000000000025183 R15: 00007ffce149e620
</TASK>
INFO: task syz.1.18:4537 blocked for more than 144 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.18 state:D stack:25728 pid:4537 ppid:4404 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
schedule+0xb9/0x180 kernel/sched/core.c:6637
rwsem_down_write_slowpath+0xbed/0x1090 kernel/locking/rwsem.c:1189
mmap_write_lock include/linux/mmap_lock.h:71 [inline]
exit_mmap+0x20f/0x8e0 mm/mmap.c:3258
__mmput+0x118/0x3c0 kernel/fork.c:1200
exit_mm+0x1e6/0x2c0 kernel/exit.c:565
do_exit+0x8c1/0x2400 kernel/exit.c:867
do_group_exit+0x217/0x2d0 kernel/exit.c:1022
__do_sys_exit_group kernel/exit.c:1033 [inline]
__se_sys_exit_group kernel/exit.c:1031 [inline]
__x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1031
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fdf37f8eec9
RSP: 002b:00007ffc504dafe8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fdf37f8eec9
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000003 R08: 00000005504db0df R09: 00007fdf381b1280
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fdf381b1280 R14: 0000000000000003 R15: 00007ffc504db0a0
</TASK>
Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
#0: ffffffff8cb2b570 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
#0: ffffffff8cb2bd90 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
#0: ffffffff8cb2abe0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#0: ffffffff8cb2abe0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#0: ffffffff8cb2abe0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513
1 lock held by dhcpcd/3932:
#0: ffffffff8cb53810 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: copy_process+0x248b/0x4020 kernel/fork.c:2446
2 locks held by getty/4030:
#0: ffff88802fa51098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
#1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41b/0x1380 drivers/tty/n_tty.c:2198
1 lock held by udevd/4311:
#0: ffff88807cd81f58 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
#0: ffff88807cd81f58 (&mm->mmap_lock){++++}-{3:3}, at: __vm_munmap+0x141/0x290 mm/mmap.c:2933
2 locks held by kworker/0:4/4318:
1 lock held by syz-executor/4393:
#0: ffffffff8cb53810 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: do_exit+0x578/0x2400 kernel/exit.c:827
2 locks held by syz-executor/4402:
#0: ffffffff8cbc4e50 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mmap kernel/fork.c:593 [inline]
#0: ffffffff8cbc4e50 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1541 [inline]
#0: ffffffff8cbc4e50 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm+0x2a9/0x15c0 kernel/fork.c:1590
#1: ffff88802866f958 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
#1: ffff88802866f958 (&mm->mmap_lock){++++}-{3:3}, at: dup_mmap kernel/fork.c:594 [inline]
#1: ffff88802866f958 (&mm->mmap_lock){++++}-{3:3}, at: dup_mm kernel/fork.c:1541 [inline]
#1: ffff88802866f958 (&mm->mmap_lock){++++}-{3:3}, at: copy_mm+0x2c3/0x15c0 kernel/fork.c:1590
1 lock held by udevd/4410:
#0: ffff88807297bd58 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
#0: ffff88807297bd58 (&mm->mmap_lock){++++}-{3:3}, at: __vm_munmap+0x141/0x290 mm/mmap.c:2933
7 locks held by syz-executor/4411:
#0: ffff888023ff0460 (sb_writers#11){.+.+}-{0:0}, at: vfs_write+0x256/0x960 fs/read_write.c:580
#1: ffff8880606d4888 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1e3/0x520 fs/kernfs/file.c:343
#2: ffffffff8cb53628 (cgroup_mutex){+.+.}-{3:3}, at: cgroup_lock include/linux/cgroup.h:442 [inline]
#2: ffffffff8cb53628 (cgroup_mutex){+.+.}-{3:3}, at: cgroup_kn_lock_live+0xee/0x230 kernel/cgroup/cgroup.c:1677
#3: ffffffff8c9c7a70 (cpu_hotplug_lock){++++}-{0:0}, at: cgroup_attach_lock kernel/cgroup/cgroup.c:2453 [inline]
#3: ffffffff8c9c7a70 (cpu_hotplug_lock){++++}-{0:0}, at: cgroup_procs_write_start+0x183/0x600 kernel/cgroup/cgroup.c:2959
#4: ffffffff8cb53810 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: cgroup_attach_lock kernel/cgroup/cgroup.c:2455 [inline]
#4: ffffffff8cb53810 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: cgroup_procs_write_start+0x199/0x600 kernel/cgroup/cgroup.c:2959
#5: ffffffff8cb61ba8 (cpuset_mutex){+.+.}-{3:3}, at: cpuset_attach+0xac/0x540 kernel/cgroup/cpuset.c:2647
#6: ffff88807297cc58 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock include/linux/mmap_lock.h:71 [inline]
#6: ffff88807297cc58 (&mm->mmap_lock){++++}-{3:3}, at: mpol_rebind_mm+0xbe/0x370 mm/mempolicy.c:386
2 locks held by kworker/u4:9/4532:
#0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#1: ffffc90003ec7d00 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
1 lock held by modprobe/4535:
#0: ffff88807470f1d8 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
#0: ffff88807470f1d8 (&mm->mmap_lock){++++}-{3:3}, at: vm_mmap_pgoff+0x15d/0x2b0 mm/util.c:518
1 lock held by syz.0.25/4536:
#0: ffff88807470f958 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock include/linux/mmap_lock.h:71 [inline]
#0: ffff88807470f958 (&mm->mmap_lock){++++}-{3:3}, at: exit_mmap+0x20f/0x8e0 mm/mmap.c:3258
1 lock held by syz.1.18/4537:
#0: ffff88801fe4ea58 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock include/linux/mmap_lock.h:71 [inline]
#0: ffff88801fe4ea58 (&mm->mmap_lock){++++}-{3:3}, at: exit_mmap+0x20f/0x8e0 mm/mmap.c:3258
=============================================
NMI backtrace for cpu 1
CPU: 1 PID: 28 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
<TASK>
dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
nmi_cpu_backtrace+0x3f4/0x470 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
watchdog+0xeee/0xf30 kernel/hung_task.c:377
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4334 Comm: kworker/u4:5 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Workqueue: bat_events batadv_nc_worker
RIP: 0010:instrument_atomic_read include/linux/instrumented.h:72 [inline]
RIP: 0010:_test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
RIP: 0010:hlock_class kernel/locking/lockdep.c:228 [inline]
RIP: 0010:__lock_acquire+0x10ad/0x7c50 kernel/locking/lockdep.c:5045
Code: 0f b6 04 00 84 c0 0f 85 68 5d 00 00 8b 03 89 c3 81 e3 ff 1f 00 00 c1 e8 03 25 f8 03 00 00 48 8d b8 40 22 ae 90 be 08 00 00 00 <e8> de e9 6d 00 48 0f a3 1d 56 1a 4b 0f 0f 83 8c 01 00 00 48 8d 04
RSP: 0018:ffffc90003e87780 EFLAGS: 00000006
RAX: 00000000000000e8 RBX: 0000000000000765 RCX: 00000000d85187a2
RDX: 0000000093ddaba0 RSI: 0000000000000008 RDI: ffffffff90ae2328
RBP: ffffc90003e879d0 R08: dffffc0000000000 R09: fffffbfff215c466
R10: fffffbfff215c466 R11: 1ffffffff215c465 R12: 00000000ab5163cb
R13: 000000007ad1ed9a R14: 000000002453d227 R15: ffff88801c73e410
FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2b99af1cd8 CR3: 000000002f730000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
_raw_spin_lock_bh+0x32/0x50 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:356 [inline]
batadv_nc_purge_paths+0xe7/0x3b0 net/batman-adv/network-coding.c:442
batadv_nc_worker+0x365/0x600 net/batman-adv/network-coding.c:722
process_one_work+0x898/0x1160 kernel/workqueue.c:2292
worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
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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
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If you want to overwrite report's subsystems, reply with:
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(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
syzbot
Sep 28, 2025, 9:21:35 PMSep 28
to syzkaller...@googlegroups.com
syzbot has found a reproducer for the following issue on:
HEAD commit: 7b34dc04e4ff Linux 6.1.154
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1304eae2580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14d3cae2580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/cb7cb7b3a100/disk-7b34dc04.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e06d58b4fc92/vmlinux-7b34dc04.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ed0693e83723/bzImage-7b34dc04.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b9b073...@syzkaller.appspotmail.com
INFO: task syz-executor:4410 blocked for more than 143 seconds.
cgroup_attach_task+0x558/0x840 kernel/cgroup/cgroup.c:2953
__cgroup1_procs_write+0x2e0/0x3e0 kernel/cgroup/cgroup-v1.c:522
cgroup_file_write+0x2f8/0x660 kernel/cgroup/cgroup.c:4100
RSP: 002b:00007ffc2d65cb10 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fcccf58d97f
RDX: 0000000000000001 RSI: 00007ffc2d65cb60 RDI: 0000000000000003
RBP: 00007ffc2d65d0d0 R08: 0000000000000000 R09: 00007ffc2d65c967
</TASK>
INFO: task kworker/u4:7:4465 blocked for more than 143 seconds.
Workqueue: events_unbound call_usermodehelper_exec_work
__percpu_down_read+0xda/0x120 kernel/locking/percpu-rwsem.c:177
percpu_down_read include/linux/percpu-rwsem.h:65 [inline]
cgroup_threadgroup_change_begin include/linux/cgroup-defs.h:748 [inline]
cgroup_css_set_fork kernel/cgroup/cgroup.c:6432 [inline]
cgroup_can_fork+0xc27/0xd30 kernel/cgroup/cgroup.c:6565
copy_process+0x248b/0x4020 kernel/fork.c:2446
kernel_clone+0x225/0x8b0 kernel/fork.c:2757
user_mode_thread+0xda/0x130 kernel/fork.c:2833
call_usermodehelper_exec_sync kernel/umh.c:136 [inline]
call_usermodehelper_exec_work+0x93/0x220 kernel/umh.c:167
RSP: 002b:00007ffca3085658 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fc06af8eec9
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000001
R13: 00000000000927c0 R14: 0000000000024cd0 R15: 00007ffca3085710
</TASK>
INFO: task modprobe:4531 blocked for more than 144 seconds.
__percpu_down_read+0xda/0x120 kernel/locking/percpu-rwsem.c:177
percpu_down_read include/linux/percpu-rwsem.h:65 [inline]
cgroup_threadgroup_change_begin include/linux/cgroup-defs.h:748 [inline]
exit_signals+0x3c0/0x4f0 kernel/signal.c:2963
do_exit+0x578/0x2400 kernel/exit.c:827
RSP: 002b:00007ffc88ba57d8 EFLAGS: 00000202 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007fb3a6753fe8 RCX: 00007fb3a66526c5
RDX: 00000000000000e7 RSI: ffffffffffffff88 RDI: 0000000000000001
RBP: 0000000000000001 R08: 00007ffc88ba5768 R09: 0000000000000000
R10: 00007ffc88ba5600 R11: 0000000000000202 R12: 0000000000000000
R13: 0000000000000001 R14: 00007fb3a6752680 R15: 00007fb3a6754000
</TASK>
INFO: task syz.2.28:4532 blocked for more than 144 seconds.
__percpu_down_read+0xda/0x120 kernel/locking/percpu-rwsem.c:177
percpu_down_read include/linux/percpu-rwsem.h:65 [inline]
cgroup_threadgroup_change_begin include/linux/cgroup-defs.h:748 [inline]
exit_signals+0x3c0/0x4f0 kernel/signal.c:2963
do_exit+0x578/0x2400 kernel/exit.c:827
RSP: 002b:00007ffd1d2286c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fa69678eec9
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000006
R13: 00000000000927c0 R14: 0000000000024eed R15: 00007ffd1d228780
#0: ffff8880b8f3aad8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:537
#1: ffffc90000b27d00 ((work_completion)(&(&bat_priv->nc.work)->work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#2: ffff8880b8f28418 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x123/0x270 kernel/time/timer.c:999
1 lock held by udevd/4376:
#0: ffff88801ff2c460 (sb_writers#11){.+.+}-{0:0}, at: vfs_write+0x256/0x960 fs/read_write.c:580
#1: ffff888076ac4088 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1e3/0x520 fs/kernfs/file.c:343
#3: ffffffff8c9c7a70 (cpu_hotplug_lock){++++}-{0:0}, at: cgroup_attach_lock kernel/cgroup/cgroup.c:2476 [inline]
#3: ffffffff8c9c7a70 (cpu_hotplug_lock){++++}-{0:0}, at: cgroup_procs_write_start+0x183/0x600 kernel/cgroup/cgroup.c:2982
#4: ffffffff8cb53810 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: cgroup_attach_lock kernel/cgroup/cgroup.c:2478 [inline]
#4: ffffffff8cb53810 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: cgroup_procs_write_start+0x199/0x600 kernel/cgroup/cgroup.c:2982
#5: ffffffff8cb61ca8 (cpuset_mutex){+.+.}-{3:3}, at: cpuset_attach+0xac/0x540 kernel/cgroup/cpuset.c:2647
#6: ffff888075618158 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock include/linux/mmap_lock.h:71 [inline]
#6: ffff888075618158 (&mm->mmap_lock){++++}-{3:3}, at: mpol_rebind_mm+0xbe/0x370 mm/mempolicy.c:386
1 lock held by udevd/4414:
#2: ffffffff8cb53810 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: copy_process+0x248b/0x4020 kernel/fork.c:2446
1 lock held by syz.0.24/4525:
#0: ffff88801d7b71d8 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock include/linux/mmap_lock.h:71 [inline]
#0: ffff88801d7b71d8 (&mm->mmap_lock){++++}-{3:3}, at: exit_mmap+0x20f/0x8e0 mm/mmap.c:3258
1 lock held by modprobe/4531:
NMI backtrace for cpu 0
CPU: 0 PID: 28 Comm: khungtaskd Not tainted syzkaller #0
Code: 85 63 62 00 00 31 c0 4c 89 b4 24 b8 00 00 00 41 83 3e 00 0f 95 c0 09 c3 c1 e3 0d 8b 84 24 c0 00 00 00 c1 e0 0f 0f b7 c0 09 d8 <8b> 8c 24 90 00 00 00 83 e1 03 c1 e1 10 09 c1 8b 44 24 34 83 e0 01
RSP: 0018:ffffc90000107840 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 1ffff11027fce8da
RDX: 000000000000002c RSI: 0000000000000000 RDI: ffff88813fe746c0
RBP: ffffc90000107a90 R08: dffffc0000000000 R09: 0000000000000000
R10: fffffbfff1c3eee6 R11: 1ffffffff1c3eee5 R12: ffff88813fe746b0
R13: 0000000000000000 R14: ffff88813fe74644 R15: 000000000000002c
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
rcu_read_lock include/linux/rcupdate.h:791 [inline]
batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline]
batadv_nc_worker+0xeb/0x600 net/batman-adv/network-coding.c:719
HEAD commit: 7b34dc04e4ff Linux 6.1.154
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1304eae2580000
kernel config: https://syzkaller.appspot.com/x/.config?x=7eb38bd5021fec61
dashboard link: https://syzkaller.appspot.com/bug?extid=b9b07367c7593c3811f2
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12b08334580000
dashboard link: https://syzkaller.appspot.com/bug?extid=b9b07367c7593c3811f2
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14d3cae2580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/cb7cb7b3a100/disk-7b34dc04.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e06d58b4fc92/vmlinux-7b34dc04.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ed0693e83723/bzImage-7b34dc04.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b9b073...@syzkaller.appspotmail.com
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor state:D stack:22560 pid:4410 ppid:4402 flags:0x00004000
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
schedule+0xb9/0x180 kernel/sched/core.c:6637
rwsem_down_write_slowpath+0xbed/0x1090 kernel/locking/rwsem.c:1189
mmap_write_lock include/linux/mmap_lock.h:71 [inline]
mpol_rebind_mm+0xbe/0x370 mm/mempolicy.c:386
cpuset_attach+0x284/0x540 kernel/cgroup/cpuset.c:2663
cgroup_migrate_execute+0x7a3/0xf30 kernel/cgroup/cgroup.c:2662
<TASK>
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
schedule+0xb9/0x180 kernel/sched/core.c:6637
rwsem_down_write_slowpath+0xbed/0x1090 kernel/locking/rwsem.c:1189
mmap_write_lock include/linux/mmap_lock.h:71 [inline]
mpol_rebind_mm+0xbe/0x370 mm/mempolicy.c:386
cpuset_attach+0x284/0x540 kernel/cgroup/cpuset.c:2663
cgroup_attach_task+0x558/0x840 kernel/cgroup/cgroup.c:2953
__cgroup1_procs_write+0x2e0/0x3e0 kernel/cgroup/cgroup-v1.c:522
cgroup_file_write+0x2f8/0x660 kernel/cgroup/cgroup.c:4100
kernfs_fop_write_iter+0x3b2/0x520 fs/kernfs/file.c:352
call_write_iter include/linux/fs.h:2265 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x44c/0x960 fs/read_write.c:584
ksys_write+0x143/0x240 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fcccf58d97f
call_write_iter include/linux/fs.h:2265 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x44c/0x960 fs/read_write.c:584
ksys_write+0x143/0x240 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RSP: 002b:00007ffc2d65cb10 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fcccf58d97f
RDX: 0000000000000001 RSI: 00007ffc2d65cb60 RDI: 0000000000000003
RBP: 00007ffc2d65d0d0 R08: 0000000000000000 R09: 00007ffc2d65c967
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001
R13: 00007ffc2d65cb60 R14: 00007ffc2d65d090 R15: 00007ffc2d65d0d0
</TASK>
INFO: task kworker/u4:7:4465 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:7 state:D stack:26464 pid:4465 ppid:2 flags:0x00004000
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
Workqueue: events_unbound call_usermodehelper_exec_work
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
schedule+0xb9/0x180 kernel/sched/core.c:6637
percpu_rwsem_wait+0x2bd/0x300 kernel/locking/percpu-rwsem.c:162
<TASK>
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
schedule+0xb9/0x180 kernel/sched/core.c:6637
__percpu_down_read+0xda/0x120 kernel/locking/percpu-rwsem.c:177
percpu_down_read include/linux/percpu-rwsem.h:65 [inline]
cgroup_threadgroup_change_begin include/linux/cgroup-defs.h:748 [inline]
cgroup_css_set_fork kernel/cgroup/cgroup.c:6432 [inline]
cgroup_can_fork+0xc27/0xd30 kernel/cgroup/cgroup.c:6565
copy_process+0x248b/0x4020 kernel/fork.c:2446
kernel_clone+0x225/0x8b0 kernel/fork.c:2757
user_mode_thread+0xda/0x130 kernel/fork.c:2833
call_usermodehelper_exec_sync kernel/umh.c:136 [inline]
call_usermodehelper_exec_work+0x93/0x220 kernel/umh.c:167
process_one_work+0x898/0x1160 kernel/workqueue.c:2292
worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
INFO: task syz.0.24:4525 blocked for more than 143 seconds.
worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.24 state:D stack:25256 pid:4525 ppid:4398 flags:0x00004000
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
schedule+0xb9/0x180 kernel/sched/core.c:6637
rwsem_down_write_slowpath+0xbed/0x1090 kernel/locking/rwsem.c:1189
mmap_write_lock include/linux/mmap_lock.h:71 [inline]
exit_mmap+0x20f/0x8e0 mm/mmap.c:3258
__mmput+0x118/0x3c0 kernel/fork.c:1200
exit_mm+0x1e6/0x2c0 kernel/exit.c:565
do_exit+0x8c1/0x2400 kernel/exit.c:867
do_group_exit+0x217/0x2d0 kernel/exit.c:1022
__do_sys_exit_group kernel/exit.c:1033 [inline]
__se_sys_exit_group kernel/exit.c:1031 [inline]
__x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1031
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fc06af8eec9
<TASK>
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
schedule+0xb9/0x180 kernel/sched/core.c:6637
rwsem_down_write_slowpath+0xbed/0x1090 kernel/locking/rwsem.c:1189
mmap_write_lock include/linux/mmap_lock.h:71 [inline]
exit_mmap+0x20f/0x8e0 mm/mmap.c:3258
__mmput+0x118/0x3c0 kernel/fork.c:1200
exit_mm+0x1e6/0x2c0 kernel/exit.c:565
do_exit+0x8c1/0x2400 kernel/exit.c:867
do_group_exit+0x217/0x2d0 kernel/exit.c:1022
__do_sys_exit_group kernel/exit.c:1033 [inline]
__se_sys_exit_group kernel/exit.c:1031 [inline]
__x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1031
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RSP: 002b:00007ffca3085658 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fc06af8eec9
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffca30856bc R08: 00000005a308574f R09: 00000000000927c0
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000001
R13: 00000000000927c0 R14: 0000000000024cd0 R15: 00007ffca3085710
</TASK>
INFO: task modprobe:4531 blocked for more than 144 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:modprobe state:D stack:24352 pid:4531 ppid:4352 flags:0x00004002
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
schedule+0xb9/0x180 kernel/sched/core.c:6637
percpu_rwsem_wait+0x2bd/0x300 kernel/locking/percpu-rwsem.c:162
<TASK>
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
schedule+0xb9/0x180 kernel/sched/core.c:6637
__percpu_down_read+0xda/0x120 kernel/locking/percpu-rwsem.c:177
percpu_down_read include/linux/percpu-rwsem.h:65 [inline]
cgroup_threadgroup_change_begin include/linux/cgroup-defs.h:748 [inline]
exit_signals+0x3c0/0x4f0 kernel/signal.c:2963
do_exit+0x578/0x2400 kernel/exit.c:827
do_group_exit+0x217/0x2d0 kernel/exit.c:1022
__do_sys_exit_group kernel/exit.c:1033 [inline]
__se_sys_exit_group kernel/exit.c:1031 [inline]
__x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1031
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fb3a66526c5
__do_sys_exit_group kernel/exit.c:1033 [inline]
__se_sys_exit_group kernel/exit.c:1031 [inline]
__x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1031
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RSP: 002b:00007ffc88ba57d8 EFLAGS: 00000202 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007fb3a6753fe8 RCX: 00007fb3a66526c5
RDX: 00000000000000e7 RSI: ffffffffffffff88 RDI: 0000000000000001
RBP: 0000000000000001 R08: 00007ffc88ba5768 R09: 0000000000000000
R10: 00007ffc88ba5600 R11: 0000000000000202 R12: 0000000000000000
R13: 0000000000000001 R14: 00007fb3a6752680 R15: 00007fb3a6754000
</TASK>
INFO: task syz.2.28:4532 blocked for more than 144 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.28 state:D stack:25728 pid:4532 ppid:4405 flags:0x00004000
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
schedule+0xb9/0x180 kernel/sched/core.c:6637
percpu_rwsem_wait+0x2bd/0x300 kernel/locking/percpu-rwsem.c:162
<TASK>
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
schedule+0xb9/0x180 kernel/sched/core.c:6637
__percpu_down_read+0xda/0x120 kernel/locking/percpu-rwsem.c:177
percpu_down_read include/linux/percpu-rwsem.h:65 [inline]
cgroup_threadgroup_change_begin include/linux/cgroup-defs.h:748 [inline]
exit_signals+0x3c0/0x4f0 kernel/signal.c:2963
do_exit+0x578/0x2400 kernel/exit.c:827
do_group_exit+0x217/0x2d0 kernel/exit.c:1022
__do_sys_exit_group kernel/exit.c:1033 [inline]
__se_sys_exit_group kernel/exit.c:1031 [inline]
__x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1031
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fa69678eec9
__do_sys_exit_group kernel/exit.c:1033 [inline]
__se_sys_exit_group kernel/exit.c:1031 [inline]
__x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1031
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RSP: 002b:00007ffd1d2286c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fa69678eec9
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffd1d22872c R08: 000000051d2287bf R09: 00000000000927c0
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000006
R13: 00000000000927c0 R14: 0000000000024eed R15: 00007ffd1d228780
</TASK>
Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
#0: ffffffff8cb2b570 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
#0: ffffffff8cb2bd90 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
#0: ffffffff8cb2abe0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#0: ffffffff8cb2abe0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#0: ffffffff8cb2abe0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513
3 locks held by kworker/u4:2/41:
Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
#0: ffffffff8cb2b570 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
#0: ffffffff8cb2bd90 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
#0: ffffffff8cb2abe0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#0: ffffffff8cb2abe0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#0: ffffffff8cb2abe0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513
#0: ffff8880b8f3aad8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:537
#1: ffffc90000b27d00 ((work_completion)(&(&bat_priv->nc.work)->work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#2: ffff8880b8f28418 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x123/0x270 kernel/time/timer.c:999
1 lock held by dhcpcd/3932:
#0: ffffffff8cb53810 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: copy_process+0x248b/0x4020 kernel/fork.c:2446
2 locks held by getty/4030:
#0: ffff88802fc84098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
#0: ffffffff8cb53810 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: copy_process+0x248b/0x4020 kernel/fork.c:2446
2 locks held by getty/4030:
#1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41b/0x1380 drivers/tty/n_tty.c:2198
1 lock held by udevd/4296:
#0: ffffffff8cb53810 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: do_exit+0x578/0x2400 kernel/exit.c:827
1 lock held by udevd/4298:
#0: ffffffff8cb53810 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: do_exit+0x578/0x2400 kernel/exit.c:827
2 locks held by kworker/u4:5/4352:
#0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#1: ffffc90003f87d00 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
1 lock held by udevd/4376:
#0: ffffffff8cb53810 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: do_exit+0x578/0x2400 kernel/exit.c:827
1 lock held by syz-executor/4396:
#0: ffffffff8cb53810 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: do_exit+0x578/0x2400 kernel/exit.c:827
7 locks held by syz-executor/4410:
#0: ffff88801ff2c460 (sb_writers#11){.+.+}-{0:0}, at: vfs_write+0x256/0x960 fs/read_write.c:580
#1: ffff888076ac4088 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1e3/0x520 fs/kernfs/file.c:343
#2: ffffffff8cb53628 (cgroup_mutex){+.+.}-{3:3}, at: cgroup_lock include/linux/cgroup.h:442 [inline]
#2: ffffffff8cb53628 (cgroup_mutex){+.+.}-{3:3}, at: cgroup_kn_lock_live+0xee/0x230 kernel/cgroup/cgroup.c:1700
#3: ffffffff8c9c7a70 (cpu_hotplug_lock){++++}-{0:0}, at: cgroup_attach_lock kernel/cgroup/cgroup.c:2476 [inline]
#3: ffffffff8c9c7a70 (cpu_hotplug_lock){++++}-{0:0}, at: cgroup_procs_write_start+0x183/0x600 kernel/cgroup/cgroup.c:2982
#4: ffffffff8cb53810 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: cgroup_attach_lock kernel/cgroup/cgroup.c:2478 [inline]
#4: ffffffff8cb53810 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: cgroup_procs_write_start+0x199/0x600 kernel/cgroup/cgroup.c:2982
#5: ffffffff8cb61ca8 (cpuset_mutex){+.+.}-{3:3}, at: cpuset_attach+0xac/0x540 kernel/cgroup/cpuset.c:2647
#6: ffff888075618158 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock include/linux/mmap_lock.h:71 [inline]
#6: ffff888075618158 (&mm->mmap_lock){++++}-{3:3}, at: mpol_rebind_mm+0xbe/0x370 mm/mempolicy.c:386
1 lock held by udevd/4414:
#0: ffffffff8cb53810 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: do_exit+0x578/0x2400 kernel/exit.c:827
3 locks held by kworker/u4:7/4465:
#0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#1: ffffc90003647d00 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#2: ffffffff8cb53810 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: copy_process+0x248b/0x4020 kernel/fork.c:2446
1 lock held by syz.0.24/4525:
#0: ffff88801d7b71d8 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock include/linux/mmap_lock.h:71 [inline]
#0: ffff88801d7b71d8 (&mm->mmap_lock){++++}-{3:3}, at: exit_mmap+0x20f/0x8e0 mm/mmap.c:3258
1 lock held by modprobe/4531:
#0: ffffffff8cb53810 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: do_exit+0x578/0x2400 kernel/exit.c:827
1 lock held by syz.2.28/4532:
#0: ffffffff8cb53810 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: do_exit+0x578/0x2400 kernel/exit.c:827
=============================================
NMI backtrace for cpu 0
CPU: 0 PID: 28 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
<TASK>
dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
nmi_cpu_backtrace+0x3f4/0x470 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
watchdog+0xeee/0xf30 kernel/hung_task.c:377
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
Sending NMI from CPU 0 to CPUs 1:
Call Trace:
<TASK>
dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
nmi_cpu_backtrace+0x3f4/0x470 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
watchdog+0xeee/0xf30 kernel/hung_task.c:377
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
NMI backtrace for cpu 1
CPU: 1 PID: 11 Comm: kworker/u4:1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Workqueue: bat_events batadv_nc_worker
RIP: 0010:__lock_acquire+0x499/0x7c50 kernel/locking/lockdep.c:4988
Workqueue: bat_events batadv_nc_worker
Code: 85 63 62 00 00 31 c0 4c 89 b4 24 b8 00 00 00 41 83 3e 00 0f 95 c0 09 c3 c1 e3 0d 8b 84 24 c0 00 00 00 c1 e0 0f 0f b7 c0 09 d8 <8b> 8c 24 90 00 00 00 83 e1 03 c1 e1 10 09 c1 8b 44 24 34 83 e0 01
RSP: 0018:ffffc90000107840 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 1ffff11027fce8da
RDX: 000000000000002c RSI: 0000000000000000 RDI: ffff88813fe746c0
RBP: ffffc90000107a90 R08: dffffc0000000000 R09: 0000000000000000
R10: fffffbfff1c3eee6 R11: 1ffffffff1c3eee5 R12: ffff88813fe746b0
R13: 0000000000000000 R14: ffff88813fe74644 R15: 000000000000002c
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fec5c249000 CR3: 0000000030da0000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
rcu_read_lock include/linux/rcupdate.h:791 [inline]
batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline]
batadv_nc_worker+0xeb/0x600 net/batman-adv/network-coding.c:719
process_one_work+0x898/0x1160 kernel/workqueue.c:2292
worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
---
worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
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