INFO: task syz.2.205:6698 blocked for more than 144 seconds.
Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.205 state:D stack:26096 pid:6698 tgid:6694 ppid:5858 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5352 [inline]
__schedule+0x1665/0x5590 kernel/sched/core.c:6964
__schedule_loop kernel/sched/core.c:7047 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7062
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7119
rwsem_down_write_slowpath+0x883/0x1080 kernel/locking/rwsem.c:1215
__down_write_common kernel/locking/rwsem.c:1347 [inline]
__down_write kernel/locking/rwsem.c:1356 [inline]
down_write+0x1bc/0x200 kernel/locking/rwsem.c:1626
mmap_write_lock include/linux/mmap_lock.h:536 [inline]
userfaultfd_register fs/userfaultfd.c:1317 [inline]
userfaultfd_ioctl+0x21fb/0x4c70 fs/userfaultfd.c:2050
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5eb579c799
RSP: 002b:00007f5eb66c0028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f5eb5a15fa0 RCX: 00007f5eb579c799
RDX: 0000200000000080 RSI: 00000000c020aa00 RDI: 0000000000000005
RBP: 00007f5eb5832c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5eb5a16038 R14: 00007f5eb5a15fa0 R15: 00007fff294161f8
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8e75d6a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#0: ffffffff8e75d6a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#0: ffffffff8e75d6a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by getty/5602:
#0: ffff888037e7f0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000322b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0 drivers/tty/n_tty.c:2211
1 lock held by udevd/6189:
1 lock held by syz.2.205/6698:
#0: ffff888034cb3538 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:536 [inline]
#0: ffff888034cb3538 (&mm->mmap_lock){++++}-{4:4}, at: userfaultfd_register fs/userfaultfd.c:1317 [inline]
#0: ffff888034cb3538 (&mm->mmap_lock){++++}-{4:4}, at: userfaultfd_ioctl+0x21fb/0x4c70 fs/userfaultfd.c:2050
1 lock held by syz.3.602/8133:
#0: ffff8880b863ae60 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x31/0x150 kernel/sched/core.c:647
2 locks held by syz.1.590/8138:
#0: ffff88807e3a4a40 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
#0: ffff88807e3a4a40 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: __sock_release+0x89/0x250 net/socket.c:724
#1: ffffffff8e7638e8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
#1: ffffffff8e7638e8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770 kernel/rcu/tree_exp.h:961
1 lock held by syz.0.605/8141:
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x135/0x170 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
watchdog+0x1002/0x1060 kernel/hung_task.c:561
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 1323 Comm: kworker/u8:7 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: bat_events batadv_mcast_mla_update
RIP: 0010:__debug_check_no_obj_freed lib/debugobjects.c:1138 [inline]
RIP: 0010:debug_check_no_obj_freed+0x534/0x550 lib/debugobjects.c:1157
Code: ff df e9 4f fe ff ff 4c 8b 74 24 30 4c 8b 7c 24 28 eb 02 31 db 48 8b 7c 24 10 48 8b 74 24 08 e8 42 54 fb 06 3b 1d f0 4e 56 0b <0f> 8e b3 fb ff ff 89 1d e4 4e 56 0b e9 a8 fb ff ff 66 66 2e 0f 1f
RSP: 0018:ffffc9000614f850 EFLAGS: 00000297
RAX: 0000000080000000 RBX: 0000000000000001 RCX: 0000000000000000
RDX: 0000000000000006 RSI: ffffffff8df3e4e9 RDI: 00000000ffffffff
RBP: 0000000000000000 R08: ffffffff90122ff7 R09: 1ffffffff20245fe
R10: dffffc0000000000 R11: fffffbfff20245ff R12: ffff888078071b20
R13: ffff888078071b00 R14: ffff888078071000 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff888125536000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0f65bfe000 CR3: 000000004a1b6000 CR4: 00000000003526f0
Call Trace:
slab_free_hook mm/slub.c:2620 [inline]
slab_free mm/slub.c:6242 [inline]
kfree+0x13e/0x650 mm/slub.c:6557
batadv_mcast_mla_list_free net/batman-adv/multicast.c:667 [inline]
__batadv_mcast_mla_update net/batman-adv/multicast.c:924 [inline]
batadv_mcast_mla_update+0x3345/0x3710 net/batman-adv/multicast.c:946
process_one_work+0x9ab/0x1780 kernel/workqueue.c:3288
process_scheduled_works kernel/workqueue.c:3379 [inline]
worker_thread+0xba8/0x11e0 kernel/workqueue.c:3465
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245