[syzbot] [net?] INFO: task hung in devlink_health_report (3)

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Nov 27, 2025, 4:42:29 PM (19 hours ago) Nov 27

to da...@davemloft.net, edum...@google.com, ho...@kernel.org, ji...@resnulli.us, ku...@kernel.org, linux-...@vger.kernel.org, net...@vger.kernel.org, pab...@redhat.com, syzkall...@googlegroups.com

Hello,

syzbot found the following issue on:

HEAD commit: 4941a17751c9 Merge tag 'trace-ringbuffer-v6.18-rc7' of git..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17e444b4580000
kernel config: https://syzkaller.appspot.com/x/.config?x=1cd7f786c0f5182f
dashboard link: https://syzkaller.appspot.com/bug?extid=11d9554b851e6081de70
compiler: gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=172fde12580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d63ef75e324b/disk-4941a177.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/9a0e19952989/vmlinux-4941a177.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c932cb5b2f37/bzImage-4941a177.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+11d955...@syzkaller.appspotmail.com

INFO: task syz.0.3521:9693 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.3521 state:D stack:27624 pid:9693 tgid:9693 ppid:8480 task_flags:0x400040 flags:0x00080002
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:7026
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7083
__mutex_lock_common kernel/locking/mutex.c:676 [inline]
__mutex_lock+0x818/0x1060 kernel/locking/mutex.c:760
devlink_health_report+0x6b4/0xb00 net/devlink/health.c:680
nsim_dev_health_break_write+0x166/0x210 drivers/net/netdevsim/health.c:162
full_proxy_write+0x131/0x1a0 fs/debugfs/file.c:388
vfs_write+0x2a0/0x11d0 fs/read_write.c:684
ksys_write+0x12a/0x250 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7efd5d18f7c9
RSP: 002b:00007fff34f08518 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007efd5d3e5fa0 RCX: 00007efd5d18f7c9
RDX: 0000000000000006 RSI: 0000200000005900 RDI: 0000000000000003
RBP: 00007efd5d213f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007efd5d3e5fa0 R14: 00007efd5d3e5fa0 R15: 0000000000000003
</TASK>

Showing all locks held in the system:
6 locks held by kworker/u8:0/12:
#0: ffff88801ba9f148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238
#1: ffffc90000117d00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239
#2: ffffffff900d4ed0 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xad/0x8b0 net/core/net_namespace.c:669
#3: ffff8880323e90e8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
#3: ffff8880323e90e8 (&dev->mutex){....}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:108 [inline]
#3: ffff8880323e90e8 (&dev->mutex){....}-{4:4}, at: devlink_pernet_pre_exit+0x12c/0x2b0 net/devlink/core.c:506
#4: ffff8880323ea250 (&devlink->lock_key#4){+.+.}-{4:4}, at: devl_lock net/devlink/core.c:276 [inline]
#4: ffff8880323ea250 (&devlink->lock_key#4){+.+.}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:109 [inline]
#4: ffff8880323ea250 (&devlink->lock_key#4){+.+.}-{4:4}, at: devlink_pernet_pre_exit+0x136/0x2b0 net/devlink/core.c:506
#5: ffff88805a336480 (&sb->s_type->i_mutex_key#3/2){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1025 [inline]
#5: ffff88805a336480 (&sb->s_type->i_mutex_key#3/2){+.+.}-{4:4}, at: __simple_recursive_removal+0x354/0x610 fs/libfs.c:627
1 lock held by khungtaskd/31:
#0: ffffffff8e3c45e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e3c45e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8e3c45e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775
2 locks held by getty/5591:
#0: ffff88814dee10a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222
5 locks held by syz-executor/9680:
#0: ffff88807da82420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#1: ffff888022f7a088 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343
#2: ffff888027e4a968 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888027e4a968 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2ff/0x570 fs/kernfs/file.c:344
#3: ffffffff8f66d0e8 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:234
#4: ffff8880323e90e8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
#4: ffff8880323e90e8 (&dev->mutex){....}-{4:4}, at: device_del+0xa0/0x9f0 drivers/base/core.c:3840
2 locks held by syz.0.3521/9693:
#0: ffff888140eea420 (sb_writers#8){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#1: ffff8880323ea250 (&devlink->lock_key#4){+.+.}-{4:4}, at: devlink_health_report+0x6b4/0xb00 net/devlink/health.c:680
2 locks held by syz.3.3545/9717:
#0: ffff888140eea420 (sb_writers#8){.+.+}-{0:0}, at: open_last_lookups fs/namei.c:3884 [inline]
#0: ffff888140eea420 (sb_writers#8){.+.+}-{0:0}, at: path_openat+0x1ec8/0x2cb0 fs/namei.c:4131
#1: ffff88805a336480 (&sb->s_type->i_mutex_key#3){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:995 [inline]
#1: ffff88805a336480 (&sb->s_type->i_mutex_key#3){++++}-{4:4}, at: open_last_lookups fs/namei.c:3894 [inline]
#1: ffff88805a336480 (&sb->s_type->i_mutex_key#3){++++}-{4:4}, at: path_openat+0x818/0x2cb0 fs/namei.c:4131
2 locks held by syz.1.3544/9718:
#0: ffff888140eea420 (sb_writers#8){.+.+}-{0:0}, at: open_last_lookups fs/namei.c:3884 [inline]
#0: ffff888140eea420 (sb_writers#8){.+.+}-{0:0}, at: path_openat+0x1ec8/0x2cb0 fs/namei.c:4131
#1: ffff88805a336480 (&sb->s_type->i_mutex_key#3){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:995 [inline]
#1: ffff88805a336480 (&sb->s_type->i_mutex_key#3){++++}-{4:4}, at: open_last_lookups fs/namei.c:3894 [inline]
#1: ffff88805a336480 (&sb->s_type->i_mutex_key#3){++++}-{4:4}, at: path_openat+0x818/0x2cb0 fs/namei.c:4131
4 locks held by syz-executor/9725:
#0: ffff88807da82420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#1: ffff88805c466c88 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343
#2: ffff888027e4a968 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888027e4a968 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2ff/0x570 fs/kernfs/file.c:344
#3: ffffffff8f66d0e8 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:234
4 locks held by syz-executor/9736:
#0: ffff88807da82420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#1: ffff88814cd6b088 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343
#2: ffff888027e4a968 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888027e4a968 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2ff/0x570 fs/kernfs/file.c:344
#3: ffffffff8f66d0e8 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:234
4 locks held by syz-executor/9738:
#0: ffff88807da82420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#1: ffff88805d4ba088 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343
#2: ffff888027e4a968 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888027e4a968 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2ff/0x570 fs/kernfs/file.c:344
#3: ffffffff8f66d0e8 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:234
4 locks held by syz-executor/9762:
#0: ffff88807da82420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#1: ffff88805e519088 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343
#2: ffff888027e4a968 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888027e4a968 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2ff/0x570 fs/kernfs/file.c:344
#3: ffffffff8f66d0e8 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:234
4 locks held by syz-executor/9773:
#0: ffff88807da82420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#1: ffff88807e784888 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343
#2: ffff888027e4a968 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888027e4a968 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2ff/0x570 fs/kernfs/file.c:344
#3: ffffffff8f66d0e8 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:234
4 locks held by syz-executor/9784:
#0: ffff88807da82420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#1: ffff888060f92488 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343
#2: ffff888027e4a968 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888027e4a968 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2ff/0x570 fs/kernfs/file.c:344
#3: ffffffff8f66d0e8 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:234
4 locks held by syz-executor/9786:
#0: ffff88807da82420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#1: ffff88805f988c88 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343
#2: ffff888027e4a968 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888027e4a968 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2ff/0x570 fs/kernfs/file.c:344
#3: ffffffff8f66d0e8 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:234
4 locks held by syz-executor/9809:
#0: ffff88807da82420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#1: ffff888031007c88 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343
#2: ffff888027e4a968 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888027e4a968 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2ff/0x570 fs/kernfs/file.c:344
#3: ffffffff8f66d0e8 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:234
4 locks held by syz-executor/9819:
#0: ffff88807da82420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#1: ffff888031eefc88 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343
#2: ffff888027e4a968 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888027e4a968 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2ff/0x570 fs/kernfs/file.c:344
#3: ffffffff8f66d0e8 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:234
4 locks held by syz-executor/9831:
#0: ffff88807da82420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#1: ffff88802d27b488 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343
#2: ffff888027e4a968 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888027e4a968 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2ff/0x570 fs/kernfs/file.c:344
#3: ffffffff8f66d0e8 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:234
4 locks held by syz-executor/9832:
#0: ffff88807da82420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#1: ffff888028813888 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343
#2: ffff888027e4a968 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888027e4a968 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2ff/0x570 fs/kernfs/file.c:344
#3: ffffffff8f66d0e8 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:234

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:332 [inline]
watchdog+0xf3f/0x1170 kernel/hung_task.c:495
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82
Code: 67 6f 02 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 23 74 2c 00 fb f4 <e9> 3c 0a 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffffff8e007df8 EFLAGS: 000002c6
RAX: 00000000001a05c3 RBX: 0000000000000000 RCX: ffffffff8b5db2a9
RDX: 0000000000000000 RSI: ffffffff8da292ea RDI: ffffffff8bf078c0
RBP: fffffbfff1c12f40 R08: 0000000000000001 R09: ffffed1017086655
R10: ffff8880b84332ab R11: 0000000000000001 R12: 0000000000000000
R13: ffffffff8e097a00 R14: ffffffff90824ad0 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888124a0d000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055b6bb661a30 CR3: 000000000e182000 CR4: 00000000003526f0
Call Trace:
<TASK>
arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
default_idle+0x13/0x20 arch/x86/kernel/process.c:767
default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:190 [inline]
do_idle+0x38d/0x500 kernel/sched/idle.c:330
cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:428
rest_init+0x16b/0x2b0 init/main.c:757
start_kernel+0x3f6/0x4e0 init/main.c:1111
x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:310
x86_64_start_kernel+0x130/0x190 arch/x86/kernel/head64.c:291
common_startup_64+0x13e/0x148
</TASK>

---
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Edward Adam Davis

unread,

Nov 27, 2025, 9:16:24 PM (14 hours ago) Nov 27

to syzbot+11d955...@syzkaller.appspotmail.com, linux-...@vger.kernel.org, syzkall...@googlegroups.com

#syz test

diff --git a/net/devlink/core.c b/net/devlink/core.c
index 58093f49c090..1ceb7a0d4bec 100644
--- a/net/devlink/core.c
+++ b/net/devlink/core.c
@@ -512,6 +512,7 @@ static void __net_exit devlink_pernet_pre_exit(struct net *net)
&actions_performed, NULL);
devl_dev_unlock(devlink, true);
devlink_put(devlink);
+ cond_resched();
if (err && err != -EOPNOTSUPP)
pr_warn("Failed to reload devlink instance into init_net\n");
}

syzbot

unread,

Nov 27, 2025, 9:56:05 PM (14 hours ago) Nov 27

to ead...@qq.com, linux-...@vger.kernel.org, syzkall...@googlegroups.com

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
INFO: task hung in remove_one

INFO: task kworker/u8:0:12 blocked for more than 143 seconds.

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

task:kworker/u8:0 state:D stack:23688 pid:12 tgid:12 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: netns cleanup_net

schedule_timeout+0x257/0x290 kernel/time/sleep_timeout.c:75
do_wait_for_common kernel/sched/completion.c:100 [inline]
__wait_for_common+0x2fc/0x4e0 kernel/sched/completion.c:121
__debugfs_file_removed fs/debugfs/inode.c:770 [inline]
remove_one+0x312/0x420 fs/debugfs/inode.c:777
__simple_recursive_removal+0x15b/0x610 fs/libfs.c:631
debugfs_remove+0x5d/0x80 fs/debugfs/inode.c:800
nsim_dev_health_exit+0x3b/0xe0 drivers/net/netdevsim/health.c:227
nsim_dev_reload_destroy+0x144/0x4d0 drivers/net/netdevsim/dev.c:1710
nsim_dev_reload_down+0x6e/0xd0 drivers/net/netdevsim/dev.c:983
devlink_reload+0x1a1/0x7c0 net/devlink/dev.c:461
devlink_pernet_pre_exit+0x1ba/0x2d0 net/devlink/core.c:509
ops_pre_exit_list net/core/net_namespace.c:161 [inline]
ops_undo_list+0x187/0xab0 net/core/net_namespace.c:234
cleanup_net+0x41b/0x8b0 net/core/net_namespace.c:695
process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3263
process_scheduled_works kernel/workqueue.c:3346 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3427

kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>

INFO: task syz-executor:11354 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:24280 pid:11354 tgid:11354 ppid:1 task_flags:0x400140 flags:0x00080002

device_lock include/linux/device.h:914 [inline]
device_del+0xa0/0x9f0 drivers/base/core.c:3840
device_unregister+0x1d/0xc0 drivers/base/core.c:3919
nsim_bus_dev_del drivers/net/netdevsim/bus.c:483 [inline]
del_device_store+0x355/0x4a0 drivers/net/netdevsim/bus.c:244
bus_attr_store+0x74/0xb0 drivers/base/bus.c:172
sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:142
kernfs_fop_write_iter+0x3af/0x570 fs/kernfs/file.c:352
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x7d3/0x11d0 fs/read_write.c:686

ksys_write+0x12a/0x250 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

RIP: 0033:0x7f7c81d8e27f
RSP: 002b:00007ffcce194960 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 00007f7c81d8e27f
RDX: 0000000000000001 RSI: 00007ffcce1949b0 RDI: 0000000000000005
RBP: 00007f7c81e152cb R08: 0000000000000000 R09: 00007ffcce1947b7
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001
R13: 00007ffcce1949b0 R14: 00007f7c82b14620 R15: 0000000000000003
</TASK>
INFO: task syz.1.2321:11371 blocked for more than 143 seconds.

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

task:syz.1.2321 state:D stack:28680 pid:11371 tgid:11370 ppid:6385 task_flags:0x400040 flags:0x00080002

Call Trace:
<TASK>
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:7026
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7083
__mutex_lock_common kernel/locking/mutex.c:676 [inline]
__mutex_lock+0x818/0x1060 kernel/locking/mutex.c:760
devlink_health_report+0x6b4/0xb00 net/devlink/health.c:680
nsim_dev_health_break_write+0x166/0x210 drivers/net/netdevsim/health.c:162
full_proxy_write+0x131/0x1a0 fs/debugfs/file.c:388
vfs_write+0x2a0/0x11d0 fs/read_write.c:684
ksys_write+0x12a/0x250 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

RIP: 0033:0x7f50a4d8f7c9
RSP: 002b:00007f50a5d13038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f50a4fe5fa0 RCX: 00007f50a4d8f7c9

RDX: 0000000000000006 RSI: 0000200000005900 RDI: 0000000000000003

RBP: 00007f50a4e13f91 R08: 0000000000000000 R09: 0000000000000000

R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000

R13: 00007f50a4fe6038 R14: 00007f50a4fe5fa0 R15: 00007ffcb9021b48
</TASK>
INFO: task syz.0.2348:11425 blocked for more than 144 seconds.

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

task:syz.0.2348 state:D stack:28480 pid:11425 tgid:11424 ppid:6386 task_flags:0x400040 flags:0x00080002

rwsem_down_read_slowpath+0x64b/0xbf0 kernel/locking/rwsem.c:1086
__down_read_common kernel/locking/rwsem.c:1261 [inline]
__down_read kernel/locking/rwsem.c:1274 [inline]
down_read+0xef/0x480 kernel/locking/rwsem.c:1539
inode_lock_shared include/linux/fs.h:995 [inline]
open_last_lookups fs/namei.c:3894 [inline]
path_openat+0x818/0x2cb0 fs/namei.c:4131
do_filp_open+0x20b/0x470 fs/namei.c:4161
do_sys_openat2+0x11b/0x1d0 fs/open.c:1437
do_sys_open fs/open.c:1452 [inline]
__do_sys_openat fs/open.c:1468 [inline]
__se_sys_openat fs/open.c:1463 [inline]
__x64_sys_openat+0x174/0x210 fs/open.c:1463

do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

RIP: 0033:0x7fbf61b8f7c9
RSP: 002b:00007fbf62986038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fbf61de5fa0 RCX: 00007fbf61b8f7c9
RDX: 0000000000048081 RSI: 0000200000000000 RDI: ffffffffffffff9c
RBP: 00007fbf61c13f91 R08: 0000000000000000 R09: 0000000000000000

R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000

R13: 00007fbf61de6038 R14: 00007fbf61de5fa0 R15: 00007ffe73b69798
</TASK>
INFO: task syz.3.2347:11428 blocked for more than 144 seconds.

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

task:syz.3.2347 state:D stack:29096 pid:11428 tgid:11427 ppid:6396 task_flags:0x400040 flags:0x00080002

do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

RIP: 0033:0x7ff49078f7c9
RSP: 002b:00007ff49169b038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007ff4909e5fa0 RCX: 00007ff49078f7c9
RDX: 0000000000048081 RSI: 0000200000000000 RDI: ffffffffffffff9c
RBP: 00007ff490813f91 R08: 0000000000000000 R09: 0000000000000000

R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000

R13: 00007ff4909e6038 R14: 00007ff4909e5fa0 R15: 00007ffd39ac8498
</TASK>
INFO: task syz-executor:11437 blocked for more than 144 seconds.

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

task:syz-executor state:D stack:24408 pid:11437 tgid:11437 ppid:1 task_flags:0x400140 flags:0x00080002

del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:234
bus_attr_store+0x74/0xb0 drivers/base/bus.c:172
sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:142
kernfs_fop_write_iter+0x3af/0x570 fs/kernfs/file.c:352
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x7d3/0x11d0 fs/read_write.c:686

ksys_write+0x12a/0x250 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

RIP: 0033:0x7fa288b8e27f
RSP: 002b:00007ffe7003a440 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 00007fa288b8e27f
RDX: 0000000000000001 RSI: 00007ffe7003a490 RDI: 0000000000000005
RBP: 00007fa288c152cb R08: 0000000000000000 R09: 00007ffe7003a297
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001
R13: 00007ffe7003a490 R14: 00007fa289914620 R15: 0000000000000003
</TASK>
INFO: task syz-executor:11440 blocked for more than 144 seconds.

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

task:syz-executor state:D stack:24056 pid:11440 tgid:11440 ppid:1 task_flags:0x400140 flags:0x00080002

ksys_write+0x12a/0x250 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

RIP: 0033:0x7f544f38e27f
RSP: 002b:00007ffe2b5411f0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 00007f544f38e27f
RDX: 0000000000000001 RSI: 00007ffe2b541240 RDI: 0000000000000005
RBP: 00007f544f4152cb R08: 0000000000000000 R09: 00007ffe2b541047
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001
R13: 00007ffe2b541240 R14: 00007f5450114620 R15: 0000000000000003
</TASK>
INFO: task syz-executor:11443 blocked for more than 145 seconds.

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

task:syz-executor state:D stack:24360 pid:11443 tgid:11443 ppid:1 task_flags:0x400140 flags:0x00080002

ksys_write+0x12a/0x250 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

RIP: 0033:0x7f150db8e27f
RSP: 002b:00007ffc9b532200 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 00007f150db8e27f
RDX: 0000000000000001 RSI: 00007ffc9b532250 RDI: 0000000000000005
RBP: 00007f150dc152cb R08: 0000000000000000 R09: 00007ffc9b532057
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001
R13: 00007ffc9b532250 R14: 00007f150e914620 R15: 0000000000000003

</TASK>

Showing all locks held in the system:
6 locks held by kworker/u8:0/12:
#0: ffff88801ba9f148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238
#1: ffffc90000117d00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239

#2: ffffffff900d5090 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xad/0x8b0 net/core/net_namespace.c:669
#3: ffff888024aad0e8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
#3: ffff888024aad0e8 (&dev->mutex){....}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:108 [inline]
#3: ffff888024aad0e8 (&dev->mutex){....}-{4:4}, at: devlink_pernet_pre_exit+0x146/0x2d0 net/devlink/core.c:506
#4: ffff888024aaa250 (&devlink->lock_key#4){+.+.}-{4:4}, at: devl_lock net/devlink/core.c:276 [inline]
#4: ffff888024aaa250 (&devlink->lock_key#4){+.+.}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:109 [inline]
#4: ffff888024aaa250 (&devlink->lock_key#4){+.+.}-{4:4}, at: devlink_pernet_pre_exit+0x150/0x2d0 net/devlink/core.c:506
#5: ffff888072350650 (&sb->s_type->i_mutex_key#3/2){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1025 [inline]
#5: ffff888072350650 (&sb->s_type->i_mutex_key#3/2){+.+.}-{4:4}, at: __simple_recursive_removal+0x354/0x610 fs/libfs.c:627
4 locks held by kworker/u8:1/13:
#0: ffff8880b843a4d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x29/0x130 kernel/sched/core.c:638
#1: ffff8880b8424088 (psi_seq){-.-.}-{0:0}, at: psi_sched_switch kernel/sched/stats.h:220 [inline]
#1: ffff8880b8424088 (psi_seq){-.-.}-{0:0}, at: __schedule+0x1861/0x5de0 kernel/sched/core.c:6923
#2: ffff8880758e0788 (&rdev->wiphy.mtx){+.+.}-{4:4}, at: class_wiphy_constructor include/net/cfg80211.h:6358 [inline]
#2: ffff8880758e0788 (&rdev->wiphy.mtx){+.+.}-{4:4}, at: cfg80211_wiphy_work+0x99/0x580 net/wireless/core.c:421
#3: ffffffff8e3c45e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#3: ffffffff8e3c45e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#3: ffffffff8e3c45e0 (rcu_read_lock){....}-{1:3}, at: ieee80211_sta_active_ibss+0xdc/0x420 net/mac80211/ibss.c:635

1 lock held by khungtaskd/31:
#0: ffffffff8e3c45e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e3c45e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8e3c45e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775

1 lock held by klogd/5186:
#0: ffff8880b843a4d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x29/0x130 kernel/sched/core.c:638
2 locks held by getty/5590:
#0: ffff88814e07d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243

#1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222

5 locks held by syz-executor/11354:
#0: ffff8880345ea420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#1: ffff888071d3bc88 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343
#2: ffff888144b58d28 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888144b58d28 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2ff/0x570 fs/kernfs/file.c:344
#3: ffffffff8f66d288 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:234
#4: ffff888024aad0e8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
#4: ffff888024aad0e8 (&dev->mutex){....}-{4:4}, at: device_del+0xa0/0x9f0 drivers/base/core.c:3840
3 locks held by syz.1.2321/11371:
#0: ffff8880321d4d38 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2a2/0x370 fs/file.c:1232
#1: ffff8881416c0420 (sb_writers#8){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#2: ffff888024aaa250 (&devlink->lock_key#4){+.+.}-{4:4}, at: devlink_health_report+0x6b4/0xb00 net/devlink/health.c:680
2 locks held by syz.0.2348/11425:
#0: ffff8881416c0420 (sb_writers#8){.+.+}-{0:0}, at: open_last_lookups fs/namei.c:3884 [inline]
#0: ffff8881416c0420 (sb_writers#8){.+.+}-{0:0}, at: path_openat+0x1ec8/0x2cb0 fs/namei.c:4131
#1: ffff888072350650 (&sb->s_type->i_mutex_key#3){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:995 [inline]
#1: ffff888072350650 (&sb->s_type->i_mutex_key#3){++++}-{4:4}, at: open_last_lookups fs/namei.c:3894 [inline]
#1: ffff888072350650 (&sb->s_type->i_mutex_key#3){++++}-{4:4}, at: path_openat+0x818/0x2cb0 fs/namei.c:4131
2 locks held by syz.3.2347/11428:
#0: ffff8881416c0420 (sb_writers#8){.+.+}-{0:0}, at: open_last_lookups fs/namei.c:3884 [inline]
#0: ffff8881416c0420 (sb_writers#8){.+.+}-{0:0}, at: path_openat+0x1ec8/0x2cb0 fs/namei.c:4131
#1: ffff888072350650 (&sb->s_type->i_mutex_key#3){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:995 [inline]
#1: ffff888072350650 (&sb->s_type->i_mutex_key#3){++++}-{4:4}, at: open_last_lookups fs/namei.c:3894 [inline]
#1: ffff888072350650 (&sb->s_type->i_mutex_key#3){++++}-{4:4}, at: path_openat+0x818/0x2cb0 fs/namei.c:4131
4 locks held by syz-executor/11437:
#0: ffff8880345ea420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#1: ffff88807b5c0088 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343
#2: ffff888144b58d28 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888144b58d28 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2ff/0x570 fs/kernfs/file.c:344
#3: ffffffff8f66d288 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:234
4 locks held by syz-executor/11440:
#0: ffff8880345ea420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#1: ffff88805ba2e888 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343
#2: ffff888144b58d28 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888144b58d28 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2ff/0x570 fs/kernfs/file.c:344
#3: ffffffff8f66d288 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:234
4 locks held by syz-executor/11443:
#0: ffff8880345ea420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#1: ffff888073969888 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343
#2: ffff888144b58d28 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888144b58d28 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2ff/0x570 fs/kernfs/file.c:344
#3: ffffffff8f66d288 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:234
4 locks held by syz-executor/11470:
#0: ffff8880345ea420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#1: ffff888059c92088 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343
#2: ffff888144b58d28 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888144b58d28 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2ff/0x570 fs/kernfs/file.c:344
#3: ffffffff8f66d288 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:234
4 locks held by syz-executor/11484:
#0: ffff8880345ea420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#1: ffff888075457488 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343
#2: ffff888144b58d28 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888144b58d28 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2ff/0x570 fs/kernfs/file.c:344
#3: ffffffff8f66d288 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:234
4 locks held by syz-executor/11486:
#0: ffff8880345ea420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#1: ffff88807e1d4888 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343
#2: ffff888144b58d28 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888144b58d28 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2ff/0x570 fs/kernfs/file.c:344
#3: ffffffff8f66d288 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:234
4 locks held by syz-executor/11490:
#0: ffff8880345ea420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#1: ffff888071d3e088 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343
#2: ffff888144b58d28 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888144b58d28 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2ff/0x570 fs/kernfs/file.c:344
#3: ffffffff8f66d288 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:234
4 locks held by syz-executor/11512:
#0: ffff8880345ea420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#1: ffff8880309f3488 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343
#2: ffff888144b58d28 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888144b58d28 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2ff/0x570 fs/kernfs/file.c:344
#3: ffffffff8f66d288 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:234
4 locks held by syz-executor/11532:
#0: ffff8880345ea420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#1: ffff88805b847888 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343
#2: ffff888144b58d28 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888144b58d28 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2ff/0x570 fs/kernfs/file.c:344
#3: ffffffff8f66d288 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:234
4 locks held by syz-executor/11533:
#0: ffff8880345ea420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#1: ffff88805b3d4c88 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343
#2: ffff888144b58d28 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888144b58d28 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2ff/0x570 fs/kernfs/file.c:344
#3: ffffffff8f66d288 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:234
4 locks held by syz-executor/11538:
#0: ffff8880345ea420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#1: ffff888071d69088 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343
#2: ffff888144b58d28 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888144b58d28 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2ff/0x570 fs/kernfs/file.c:344
#3: ffffffff8f66d288 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:234

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:332 [inline]
watchdog+0xf3f/0x1170 kernel/hung_task.c:495
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82

Code: 57 6f 02 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 23 64 2c 00 fb f4 <e9> 3c 0a 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90

RSP: 0018:ffffffff8e007df8 EFLAGS: 000002c6

RAX: 00000000001aec9d RBX: 0000000000000000 RCX: ffffffff8b5dc2a9
RDX: 0000000000000000 RSI: ffffffff8da29704 RDI: ffffffff8bf078c0

RBP: fffffbfff1c12f40 R08: 0000000000000001 R09: ffffed1017086655
R10: ffff8880b84332ab R11: 0000000000000001 R12: 0000000000000000

R13: ffffffff8e097a00 R14: ffffffff908251d0 R15: 0000000000000000

FS: 0000000000000000(0000) GS:ffff888124a0d000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 00007f951f5bde80 CR3: 000000000e182000 CR4: 00000000003526f0

Call Trace:
<TASK>
arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
default_idle+0x13/0x20 arch/x86/kernel/process.c:767
default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:190 [inline]
do_idle+0x38d/0x500 kernel/sched/idle.c:330
cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:428
rest_init+0x16b/0x2b0 init/main.c:757
start_kernel+0x3f6/0x4e0 init/main.c:1111
x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:310
x86_64_start_kernel+0x130/0x190 arch/x86/kernel/head64.c:291
common_startup_64+0x13e/0x148
</TASK>

Tested on:

commit: aa7243aa Merge tag 'dma-mapping-6.18-2025-11-27' of gi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=130e1f42580000

kernel config: https://syzkaller.appspot.com/x/.config?x=1cd7f786c0f5182f
dashboard link: https://syzkaller.appspot.com/bug?extid=11d9554b851e6081de70
compiler: gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=15262e12580000

Edward Adam Davis

unread,

3:52 AM (8 hours ago) 3:52 AM

to syzbot+11d955...@syzkaller.appspotmail.com, linux-...@vger.kernel.org, syzkall...@googlegroups.com

#syz test

diff --git a/net/devlink/core.c b/net/devlink/core.c

index 58093f49c090..d66eb5387d2d 100644
--- a/net/devlink/core.c
+++ b/net/devlink/core.c
@@ -503,6 +503,7 @@ static void __net_exit devlink_pernet_pre_exit(struct net *net)
* all devlink instances from this namespace into init_net.
*/
devlinks_xa_for_each_registered_get(net, index, devlink) {
+ cond_resched();
devl_dev_lock(devlink, true);
err = 0;
if (devl_is_registered(devlink))

syzbot

unread,

4:12 AM (8 hours ago) 4:12 AM

to ead...@qq.com, linux-...@vger.kernel.org, syzkall...@googlegroups.com

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
INFO: task hung in remove_one

INFO: task kworker/u8:9:1158 blocked for more than 143 seconds.

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

task:kworker/u8:9 state:D stack:24472 pid:1158 tgid:1158 ppid:2 task_flags:0x4208060 flags:0x00080000

Workqueue: netns cleanup_net
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:7026
schedule_timeout+0x257/0x290 kernel/time/sleep_timeout.c:75
do_wait_for_common kernel/sched/completion.c:100 [inline]
__wait_for_common+0x2fc/0x4e0 kernel/sched/completion.c:121
__debugfs_file_removed fs/debugfs/inode.c:770 [inline]
remove_one+0x312/0x420 fs/debugfs/inode.c:777
__simple_recursive_removal+0x15b/0x610 fs/libfs.c:631
debugfs_remove+0x5d/0x80 fs/debugfs/inode.c:800
nsim_dev_health_exit+0x3b/0xe0 drivers/net/netdevsim/health.c:227
nsim_dev_reload_destroy+0x144/0x4d0 drivers/net/netdevsim/dev.c:1710
nsim_dev_reload_down+0x6e/0xd0 drivers/net/netdevsim/dev.c:983
devlink_reload+0x1a1/0x7c0 net/devlink/dev.c:461

devlink_pernet_pre_exit+0x1b8/0x2c0 net/devlink/core.c:510

ops_pre_exit_list net/core/net_namespace.c:161 [inline]
ops_undo_list+0x187/0xab0 net/core/net_namespace.c:234
cleanup_net+0x41b/0x8b0 net/core/net_namespace.c:695
process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3263
process_scheduled_works kernel/workqueue.c:3346 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3427
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
INFO: task syz-executor:11435 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:23720 pid:11435 tgid:11435 ppid:1 task_flags:0x400140 flags:0x00080002

Call Trace:
<TASK>
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:7026
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7083
__mutex_lock_common kernel/locking/mutex.c:676 [inline]
__mutex_lock+0x818/0x1060 kernel/locking/mutex.c:760
device_lock include/linux/device.h:914 [inline]
device_del+0xa0/0x9f0 drivers/base/core.c:3840
device_unregister+0x1d/0xc0 drivers/base/core.c:3919
nsim_bus_dev_del drivers/net/netdevsim/bus.c:483 [inline]
del_device_store+0x355/0x4a0 drivers/net/netdevsim/bus.c:244
bus_attr_store+0x74/0xb0 drivers/base/bus.c:172
sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:142
kernfs_fop_write_iter+0x3af/0x570 fs/kernfs/file.c:352
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x7d3/0x11d0 fs/read_write.c:686
ksys_write+0x12a/0x250 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

RIP: 0033:0x7ff03d78e27f
RSP: 002b:00007ffcb83e5ab0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 00007ff03d78e27f
RDX: 0000000000000001 RSI: 00007ffcb83e5b00 RDI: 0000000000000005
RBP: 00007ff03d8152cb R08: 0000000000000000 R09: 00007ffcb83e5907

R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001

R13: 00007ffcb83e5b00 R14: 00007ff03e514620 R15: 0000000000000003
</TASK>
INFO: task syz.3.2358:11455 blocked for more than 143 seconds.

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

task:syz.3.2358 state:D stack:28856 pid:11455 tgid:11453 ppid:6409 task_flags:0x400040 flags:0x00080002

RIP: 0033:0x7fca8398f7c9
RSP: 002b:00007fca8490b038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fca83be5fa0 RCX: 00007fca8398f7c9

RDX: 0000000000000006 RSI: 0000200000005900 RDI: 0000000000000003

RBP: 00007fca83a13f91 R08: 0000000000000000 R09: 0000000000000000

R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000

R13: 00007fca83be6038 R14: 00007fca83be5fa0 R15: 00007ffed5e04d38
</TASK>
INFO: task syz.0.2377:11497 blocked for more than 144 seconds.

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

task:syz.0.2377 state:D stack:29096 pid:11497 tgid:11496 ppid:6395 task_flags:0x400040 flags:0x00080002

Call Trace:
<TASK>
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:7026
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7083
rwsem_down_read_slowpath+0x64b/0xbf0 kernel/locking/rwsem.c:1086
__down_read_common kernel/locking/rwsem.c:1261 [inline]
__down_read kernel/locking/rwsem.c:1274 [inline]
down_read+0xef/0x480 kernel/locking/rwsem.c:1539
inode_lock_shared include/linux/fs.h:995 [inline]
open_last_lookups fs/namei.c:3894 [inline]
path_openat+0x818/0x2cb0 fs/namei.c:4131
do_filp_open+0x20b/0x470 fs/namei.c:4161
do_sys_openat2+0x11b/0x1d0 fs/open.c:1437
do_sys_open fs/open.c:1452 [inline]
__do_sys_openat fs/open.c:1468 [inline]
__se_sys_openat fs/open.c:1463 [inline]
__x64_sys_openat+0x174/0x210 fs/open.c:1463
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

RIP: 0033:0x7f693bf8f7c9
RSP: 002b:00007f693ce55038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f693c1e5fa0 RCX: 00007f693bf8f7c9

RDX: 0000000000048081 RSI: 0000200000000000 RDI: ffffffffffffff9c

RBP: 00007f693c013f91 R08: 0000000000000000 R09: 0000000000000000

R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000

R13: 00007f693c1e6038 R14: 00007f693c1e5fa0 R15: 00007ffd737e93b8
</TASK>
INFO: task syz.1.2378:11500 blocked for more than 144 seconds.

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

task:syz.1.2378 state:D stack:28432 pid:11500 tgid:11498 ppid:6397 task_flags:0x400040 flags:0x00080002

Call Trace:
<TASK>
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:7026
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7083
rwsem_down_read_slowpath+0x64b/0xbf0 kernel/locking/rwsem.c:1086
__down_read_common kernel/locking/rwsem.c:1261 [inline]
__down_read kernel/locking/rwsem.c:1274 [inline]
down_read+0xef/0x480 kernel/locking/rwsem.c:1539
inode_lock_shared include/linux/fs.h:995 [inline]
open_last_lookups fs/namei.c:3894 [inline]
path_openat+0x818/0x2cb0 fs/namei.c:4131
do_filp_open+0x20b/0x470 fs/namei.c:4161
do_sys_openat2+0x11b/0x1d0 fs/open.c:1437
do_sys_open fs/open.c:1452 [inline]
__do_sys_openat fs/open.c:1468 [inline]
__se_sys_openat fs/open.c:1463 [inline]
__x64_sys_openat+0x174/0x210 fs/open.c:1463
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

RIP: 0033:0x7f0217d8f7c9
RSP: 002b:00007f0218c82038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f0217fe5fa0 RCX: 00007f0217d8f7c9

RDX: 0000000000048081 RSI: 0000200000000000 RDI: ffffffffffffff9c

RBP: 00007f0217e13f91 R08: 0000000000000000 R09: 0000000000000000

R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000

R13: 00007f0217fe6038 R14: 00007f0217fe5fa0 R15: 00007ffc44959248

</TASK>

Showing all locks held in the system:

6 locks held by kworker/u8:9/1158:

#0: ffff88801ba9f148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238

#1: ffffc90003e4fd00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239

#2: ffffffff900d5090 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xad/0x8b0 net/core/net_namespace.c:669

#3: ffff88802128f0e8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
#3: ffff88802128f0e8 (&dev->mutex){....}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:108 [inline]
#3: ffff88802128f0e8 (&dev->mutex){....}-{4:4}, at: devlink_pernet_pre_exit+0x144/0x2c0 net/devlink/core.c:507
#4: ffff88807a393250 (&devlink->lock_key#5){+.+.}-{4:4}, at: devl_lock net/devlink/core.c:276 [inline]
#4: ffff88807a393250 (&devlink->lock_key#5){+.+.}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:109 [inline]
#4: ffff88807a393250 (&devlink->lock_key#5){+.+.}-{4:4}, at: devlink_pernet_pre_exit+0x14e/0x2c0 net/devlink/core.c:507
#5: ffff888072ff3398 (&sb->s_type->i_mutex_key#3/2){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1025 [inline]
#5: ffff888072ff3398 (&sb->s_type->i_mutex_key#3/2){+.+.}-{4:4}, at: __simple_recursive_removal+0x354/0x610 fs/libfs.c:627
1 lock held by klogd/5190:

#0: ffff8880b843a4d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x29/0x130 kernel/sched/core.c:638

2 locks held by getty/5593:
#0: ffff88803469d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243

#1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222
5 locks held by syz-executor/11435:

#0: ffff88807f52a420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#1: ffff888076d95c88 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343
#2: ffff888144f46788 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888144f46788 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2ff/0x570 fs/kernfs/file.c:344

#3: ffffffff8f66d288 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:234

#4: ffff88802128f0e8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
#4: ffff88802128f0e8 (&dev->mutex){....}-{4:4}, at: device_del+0xa0/0x9f0 drivers/base/core.c:3840
3 locks held by syz.3.2358/11455:
#0: ffff88803023beb8 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2a2/0x370 fs/file.c:1232
#1: ffff888141ad0420 (sb_writers#8){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#2: ffff88807a393250 (&devlink->lock_key#5){+.+.}-{4:4}, at: devlink_health_report+0x6b4/0xb00 net/devlink/health.c:680
2 locks held by syz.0.2377/11497:
#0: ffff888141ad0420 (sb_writers#8){.+.+}-{0:0}, at: open_last_lookups fs/namei.c:3884 [inline]
#0: ffff888141ad0420 (sb_writers#8){.+.+}-{0:0}, at: path_openat+0x1ec8/0x2cb0 fs/namei.c:4131
#1: ffff888072ff3398 (&sb->s_type->i_mutex_key#3){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:995 [inline]
#1: ffff888072ff3398 (&sb->s_type->i_mutex_key#3){++++}-{4:4}, at: open_last_lookups fs/namei.c:3894 [inline]
#1: ffff888072ff3398 (&sb->s_type->i_mutex_key#3){++++}-{4:4}, at: path_openat+0x818/0x2cb0 fs/namei.c:4131
2 locks held by syz.1.2378/11500:
#0: ffff888141ad0420 (sb_writers#8){.+.+}-{0:0}, at: open_last_lookups fs/namei.c:3884 [inline]
#0: ffff888141ad0420 (sb_writers#8){.+.+}-{0:0}, at: path_openat+0x1ec8/0x2cb0 fs/namei.c:4131
#1: ffff888072ff3398 (&sb->s_type->i_mutex_key#3){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:995 [inline]
#1: ffff888072ff3398 (&sb->s_type->i_mutex_key#3){++++}-{4:4}, at: open_last_lookups fs/namei.c:3894 [inline]
#1: ffff888072ff3398 (&sb->s_type->i_mutex_key#3){++++}-{4:4}, at: path_openat+0x818/0x2cb0 fs/namei.c:4131
4 locks held by syz-executor/11508:
#0: ffff88807f52a420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#1: ffff88802785c088 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343
#2: ffff888144f46788 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888144f46788 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2ff/0x570 fs/kernfs/file.c:344

#3: ffffffff8f66d288 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:234

4 locks held by syz-executor/11509:
#0: ffff88807f52a420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#1: ffff888072ab5c88 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343
#2: ffff888144f46788 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888144f46788 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2ff/0x570 fs/kernfs/file.c:344

#3: ffffffff8f66d288 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:234

4 locks held by syz-executor/11513:
#0: ffff88807f52a420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#1: ffff8880718cf888 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343
#2: ffff888144f46788 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888144f46788 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2ff/0x570 fs/kernfs/file.c:344

#3: ffffffff8f66d288 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:234

4 locks held by syz-executor/11542:
#0: ffff88807f52a420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#1: ffff888055217488 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343
#2: ffff888144f46788 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888144f46788 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2ff/0x570 fs/kernfs/file.c:344

#3: ffffffff8f66d288 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:234

4 locks held by syz-executor/11557:
#0: ffff88807f52a420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#1: ffff88805b35c488 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343
#2: ffff888144f46788 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888144f46788 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2ff/0x570 fs/kernfs/file.c:344

#3: ffffffff8f66d288 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:234

4 locks held by syz-executor/11558:
#0: ffff88807f52a420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#1: ffff8880550b0c88 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343
#2: ffff888144f46788 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888144f46788 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2ff/0x570 fs/kernfs/file.c:344

#3: ffffffff8f66d288 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:234

4 locks held by syz-executor/11561:
#0: ffff88807f52a420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#1: ffff8880599b0c88 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343
#2: ffff888144f46788 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888144f46788 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2ff/0x570 fs/kernfs/file.c:344

#3: ffffffff8f66d288 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:234

4 locks held by syz-executor/11588:
#0: ffff88807f52a420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#1: ffff88801bf8f888 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343
#2: ffff888144f46788 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888144f46788 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2ff/0x570 fs/kernfs/file.c:344

#3: ffffffff8f66d288 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:234

4 locks held by syz-executor/11606:
#0: ffff88807f52a420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#1: ffff88807e9cec88 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343
#2: ffff888144f46788 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888144f46788 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2ff/0x570 fs/kernfs/file.c:344

#3: ffffffff8f66d288 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:234

4 locks held by syz-executor/11607:
#0: ffff88807f52a420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#1: ffff88801e2c1088 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343
#2: ffff888144f46788 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888144f46788 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2ff/0x570 fs/kernfs/file.c:344

#3: ffffffff8f66d288 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:234

4 locks held by syz-executor/11611:
#0: ffff88807f52a420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#1: ffff88805cc85488 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343
#2: ffff888144f46788 (kn->active#58){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888144f46788 (kn->active#58){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2ff/0x570 fs/kernfs/file.c:344

#3: ffffffff8f66d288 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:234

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

NMI backtrace for cpu 0

CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:332 [inline]
watchdog+0xf3f/0x1170 kernel/hung_task.c:495
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>

Sending NMI from CPU 0 to CPUs 1:

NMI backtrace for cpu 1

CPU: 1 UID: 0 PID: 12 Comm: kworker/u8:0 Not tainted syzkaller #0 PREEMPT(full)

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025

Workqueue: events_unbound cfg80211_wiphy_work
RIP: 0010:skb_kfree_head net/core/skbuff.c:1046 [inline]
RIP: 0010:skb_kfree_head net/core/skbuff.c:1043 [inline]
RIP: 0010:skb_free_head+0x19e/0x210 net/core/skbuff.c:1060
Code: 84 1e ff ff ff 48 83 c4 08 5b 5d 41 5c 41 5d e9 a8 f7 93 f8 e8 a3 f7 93 f8 48 c7 c0 e0 6d 06 8e 48 ba 00 00 00 00 00 fc ff df <48> c1 e8 03 80 3c 10 00 75 3c 48 8b 3d d1 0d de 04 4c 89 ee e8 69
RSP: 0018:ffffc90000117ac8 EFLAGS: 00000293
RAX: ffffffff8e066de0 RBX: 0000000000000180 RCX: ffffffff89285f5b
RDX: dffffc0000000000 RSI: ffffffff89285fed RDI: 0000000000000005
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000180
R10: 0000000000000180 R11: 0000000000002b81 R12: 0000000000000000
R13: ffff888074101380 R14: ffff888032c7e210 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888124b0d000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 000055d26edc1088 CR3: 000000000e182000 CR4: 00000000003526f0
Call Trace:
<TASK>
skb_release_data+0x795/0x9e0 net/core/skbuff.c:1087
skb_release_all net/core/skbuff.c:1152 [inline]
__kfree_skb net/core/skbuff.c:1166 [inline]
sk_skb_reason_drop+0x129/0x1a0 net/core/skbuff.c:1204
kfree_skb_reason include/linux/skbuff.h:1322 [inline]
kfree_skb include/linux/skbuff.h:1331 [inline]
ieee80211_iface_work+0x435/0x1360 net/mac80211/iface.c:1758
cfg80211_wiphy_work+0x2c7/0x580 net/wireless/core.c:435

process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3263
process_scheduled_works kernel/workqueue.c:3346 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3427
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>

Tested on:

commit: e538109a Merge tag 'drm-fixes-2025-11-28' of https://g..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=107cae12580000