INFO: task syz.5.347:7249 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.5.347 state:D stack:25624 pid:7249 tgid:7248 ppid:6397 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x1b2a/0x59a0 kernel/sched/core.c:7232
__schedule_loop kernel/sched/core.c:7309 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7324
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7381
__mutex_lock_common kernel/locking/mutex.c:726 [inline]
__mutex_lock+0x7bf/0x1550 kernel/locking/mutex.c:821
sync_bdevs+0x276/0x470 block/bdev.c:1370
ksys_sync fs/sync.c:105 [inline]
__ia32_sys_sync+0xc5/0x120 fs/sync.c:111
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x510 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f21d1b9e0d9
RSP: 002b:00007f21d2a28028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f21d1e25fa0 RCX: 00007f21d1b9e0d9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f21d1e25fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f21d1e26038 R14: 00007f21d1e25fa0 R15: 00007ffe29974b18
Showing all locks held in the system:
locks held by pool_workqueue_/3: 1, on CPU#0:
#0: ffffffff8eb62a68 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline]
#0: ffffffff8eb62a68 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770 kernel/rcu/tree_exp.h:966
locks held by khungtaskd/32: 1, last CPU#1:
#0: ffffffff8eb5c6a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffffffff8eb5c6a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff8eb5c6a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6837
locks held by kworker/1:1H/1729: 2, last CPU#1:
#0: ffff88801b02ed40 ((wq_completion)events_highpri){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff88801b02ed40 ((wq_completion)events_highpri){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff88801b02ed40 ((wq_completion)events_highpri){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3340 [inline]
#0: ffff88801b02ed40 ((wq_completion)events_highpri){+.+.}-{0:0}, at: process_scheduled_works+0x97e/0x1630 kernel/workqueue.c:3458
#1: ffffc900063b7c40 ((work_completion)(&vmidi->output_work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc900063b7c40 ((work_completion)(&vmidi->output_work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc900063b7c40 ((work_completion)(&vmidi->output_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3340 [inline]
#1: ffffc900063b7c40 ((work_completion)(&vmidi->output_work)){+.+.}-{0:0}, at: process_scheduled_works+0x97e/0x1630 kernel/workqueue.c:3458
locks held by getty/5372: 2, on CPU#1:
#0: ffff888034b680a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc900032262e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360 drivers/tty/n_tty.c:2211
locks held by udevd/5626: 1, last CPU#0:
#0: ffff888035b7d038 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:562 [inline]
#0: ffff888035b7d038 (&mm->mmap_lock){++++}-{4:4}, at: __vm_munmap+0x163/0x3e0 mm/vma.c:3425
locks held by udevd/5627: 1, on CPU#0:
#0: ffff8880272c5350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xde/0xd70 block/bdev.c:991
locks held by kworker/0:9/5821: 3, last CPU#0:
#0: ffff88801b02dd40 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff88801b02dd40 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff88801b02dd40 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3340 [inline]
#0: ffff88801b02dd40 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_scheduled_works+0x97e/0x1630 kernel/workqueue.c:3458
#1: ffffc900049afc40 ((work_completion)(&(&tbl->gc_work)->work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc900049afc40 ((work_completion)(&(&tbl->gc_work)->work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc900049afc40 ((work_completion)(&(&tbl->gc_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3340 [inline]
#1: ffffc900049afc40 ((work_completion)(&(&tbl->gc_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x97e/0x1630 kernel/workqueue.c:3458
#2: ffffffff9016d458 (&tbl->lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:348 [inline]
#2: ffffffff9016d458 (&tbl->lock){+.-.}-{3:3}, at: neigh_periodic_work+0xc43/0xe40 net/core/neighbour.c:1037
locks held by syz.5.347/7249: 1, on CPU#1:
#0: ffff8880272c5350 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x276/0x470 block/bdev.c:1370
locks held by udevd/8368: 2, last CPU#0:
#0: ffff88801b134378 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_downgrade include/linux/mmap_lock.h:594 [inline]
#0: ffff88801b134378 (&mm->mmap_lock){++++}-{4:4}, at: vms_complete_munmap_vmas+0x224/0xbe0 mm/vma.c:1420
#1: ffff88807e874070 (&anon_vma->rwsem){++++}-{4:4}, at: anon_vma_lock_read mm/internal.h:313 [inline]
#1: ffff88807e874070 (&anon_vma->rwsem){++++}-{4:4}, at: validate_mm+0x1f2/0x4f0 mm/vma.c:724
locks held by udevd/8688: 1, last CPU#1:
#0: ffffffff8eb5c6a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffffffff8eb5c6a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff8eb5c6a0 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1216 [inline]
#0: ffffffff8eb5c6a0 (rcu_read_lock){....}-{1:3}, at: unwind_next_frame+0x8f/0x2550 arch/x86/kernel/unwind_orc.c:495
locks held by syz.2.705/9452: 5, last CPU#1:
#0: ffff88807d124460 (sb_writers#14){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:494
#1: ffff888068dc18d0 (&inode->i_sb->s_type->i_mutex_dir_key/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1070 [inline]
#1: ffff888068dc18d0 (&inode->i_sb->s_type->i_mutex_dir_key/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2918 [inline]
#1: ffff888068dc18d0 (&inode->i_sb->s_type->i_mutex_dir_key/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2942 [inline]
#1: ffff888068dc18d0 (&inode->i_sb->s_type->i_mutex_dir_key/1){+.+.}-{4:4}, at: filename_create+0x200/0x370 fs/namei.c:5092
#2: ffff888068dc16c0 (&xfs_dir_ilock_class/5){+.+.}-{4:4}, at: xfs_create+0x562/0xa60 fs/xfs/xfs_inode.c:705
#3: ffff888068e096c0 (&xfs_dir_ilock_class/1){+.+.}-{4:4}, at: xfs_ilock_nowait+0x239/0x520 fs/xfs/xfs_inode.c:208
#4: ffffffff8eb5c6a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#4: ffffffff8eb5c6a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#4: ffffffff8eb5c6a0 (rcu_read_lock){....}-{1:3}, at: blkg_tryget_closest block/blk-cgroup.c:2082 [inline]
#4: ffffffff8eb5c6a0 (rcu_read_lock){....}-{1:3}, at: bio_associate_blkg_from_css+0x10a/0xf80 block/blk-cgroup.c:2125
locks held by syz.2.705/9454: 3, last CPU#0:
#0: ffff88807d124460 (sb_writers#14){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2754 [inline]
#0: ffff88807d124460 (sb_writers#14){.+.+}-{0:0}, at: vfs_fallocate+0x5e0/0x7e0 fs/open.c:337
#1: ffff888068e0a010 (&sb->s_type->i_mutex_key#25){++++}-{4:4}, at: xfs_ilock+0xee/0x380 fs/xfs/xfs_inode.c:149
#2: ffff888068e0a1a8 (mapping.invalidate_lock#3){++++}-{4:4}, at: xfs_ilock+0x16c/0x380 fs/xfs/xfs_inode.c:157
locks held by udevadm/9437: 2, last CPU#1:
#0: ffff8880261b1d38 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:544 [inline]
#0: ffff8880261b1d38 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x2d8/0x9f0 mm/mmap.c:1323
#1: ffffffff8eb5c6a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffffff8eb5c6a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffffff8eb5c6a0 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1216 [inline]
#1: ffffffff8eb5c6a0 (rcu_read_lock){....}-{1:3}, at: unwind_next_frame+0x8f/0x2550 arch/x86/kernel/unwind_orc.c:495
locks held by syz.7.710/9440: 1, last CPU#1:
#0: ffff88801b0569b8 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock include/linux/mmap_lock.h:600 [inline]
#0: ffff88801b0569b8 (&mm->mmap_lock){++++}-{4:4}, at: acct_collect+0x194/0x7b0 kernel/acct.c:568
locks held by syz.8.713/9455: 1, on CPU#0:
#0: ffff8880261b69b8 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock_killable+0x1d/0x70 include/linux/mmap_lock.h:609
locks held by syz.8.713/9456: 4, last CPU#1:
#0: ffffffff8ec2ee10 (dup_mmap_sem){++++}-{0:0}, at: dup_mm kernel/fork.c:1548 [inline]
#0: ffffffff8ec2ee10 (dup_mmap_sem){++++}-{0:0}, at: copy_mm+0x10f/0x480 kernel/fork.c:1601
#1: ffff8880261b69b8 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:562 [inline]
#1: ffff8880261b69b8 (&mm->mmap_lock){++++}-{4:4}, at: dup_mmap+0x195/0x1dc0 mm/mmap.c:1716
#2: ffff8880261b29f8 (&mm->mmap_lock/1){+.+.}-{4:4}, at: mmap_write_lock_nested include/linux/mmap_lock.h:552 [inline]
#2: ffff8880261b29f8 (&mm->mmap_lock/1){+.+.}-{4:4}, at: dup_mmap+0x221/0x1dc0 mm/mmap.c:1723
#3: ffffffff8eca4af0 (remove_cache_srcu){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:198 [inline]
#3: ffffffff8eca4af0 (remove_cache_srcu){.+.+}-{0:0}, at: srcu_read_lock+0x27/0x60 include/linux/srcu.h:305
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 32 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:123
nmi_trigger_cpumask_backtrace+0x17a/0x380 lib/nmi_backtrace.c:66
trigger_all_cpu_backtrace include/linux/nmi.h:164 [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+0xfd7/0x1030 kernel/hung_task.c:561
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 5821 Comm: kworker/0:9 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: events_power_efficient neigh_periodic_work
RIP: 0010:mark_lock+0x9c/0x190 kernel/locking/lockdep.c:4790
Code: 0e 00 75 13 48 8d 3d 43 fa b8 0e 48 c7 c6 76 bb 37 8e 67 48 0f b9 3a 90 31 c9 4c 89 fe 4c 89 f7 b8 01 00 00 00 85 69 60 74 10 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 85 f8 3a 0a cc 49 89 fe 49 89 f7
RSP: 0018:ffffc900049af740 EFLAGS: 00000002
RAX: 0000000000000001 RBX: 0000000000000002 RCX: ffffffff94191170
RDX: 0000000000000002 RSI: ffff888031c36a38 RDI: ffff888031c35dc0
RBP: 0000000000000004 R08: 6600000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: ffff8880b86397a0 R12: 0000000000000003
R13: 0000000000000000 R14: ffff888031c36a38 R15: 0000000000000005
FS: 0000000000000000(0000) GS:ffff888124f0c000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f855a0bcff8 CR3: 0000000065516000 CR4: 00000000003526f0
Call Trace:
mark_usage kernel/locking/lockdep.c:4678 [inline]
__lock_acquire+0x9ee/0x2e50 kernel/locking/lockdep.c:5208
lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5908
local_lock_acquire include/linux/local_lock_internal.h:46 [inline]
napi_skb_cache_get+0x169/0x7d0 net/core/skbuff.c:289
__alloc_skb+0x19d/0x7a0 net/core/skbuff.c:698
alloc_skb include/linux/skbuff.h:1384 [inline]
nlmsg_new include/net/netlink.h:1055 [inline]
__neigh_notify+0x15c/0x310 net/core/neighbour.c:3566
neigh_notify net/core/neighbour.c:3588 [inline]
neigh_cleanup_and_release+0xae/0x2b0 net/core/neighbour.c:119
neigh_periodic_work+0xb4a/0xe40 net/core/neighbour.c:1026
process_one_work kernel/workqueue.c:3375 [inline]
process_scheduled_works+0xc4e/0x1630 kernel/workqueue.c:3458
worker_thread+0xa47/0xfb0 kernel/workqueue.c:3539
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245