INFO: task syz.8.4134:26770 blocked for more than 143 seconds. Not tainted 6.12.0-syzkaller-09073-g9f16d5e6f220 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.8.4134 state:D stack:23024 pid:26770 tgid:26768 ppid:26447 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5369 [inline] __schedule+0x1850/0x4c30 kernel/sched/core.c:6756 __schedule_loop kernel/sched/core.c:6833 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6848 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6905 __mutex_lock_common kernel/locking/mutex.c:665 [inline] __mutex_lock+0x7e7/0xee0 kernel/locking/mutex.c:735 exfat_sync_fs+0xb0/0x160 fs/exfat/super.c:56 iterate_supers+0xc8/0x190 fs/super.c:934 ksys_sync+0xdb/0x1c0 fs/sync.c:104 __do_sys_sync+0xe/0x20 fs/sync.c:113 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f516df7e819 RSP: 002b:00007f516ec95038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 00007f516e135fa0 RCX: 00007f516df7e819 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f516e135fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f516e135fa0 R15: 00007fff0eac5c28 Showing all locks held in the system: 1 lock held by khungtaskd/30: #0: ffffffff8e93c520 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #0: ffffffff8e93c520 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff8e93c520 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6744 2 locks held by getty/5596: #0: ffff888030fdc0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900033132f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x6a6/0x1e00 drivers/tty/n_tty.c:2211 3 locks held by kworker/1:4/5907: #0: ffff8881412d7548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline] #0: ffff8881412d7548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1850 kernel/workqueue.c:3310 #1: ffffc9000342fd00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline] #1: ffffc9000342fd00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310 #2: ffff888145bda190 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1014 [inline] ffff888145bda190 (&dev->mutex){....}-{4:4}, at: hub_event+0x1fe/0x5150 drivers/usb/core/hub.c:5849 3 locks held by kworker/u8:10/7601: 3 locks held by syz-executor/13969: 2 locks held by syz.8.4134/26770: #0: ffff8880540400e0 (&type->s_umount_key#70){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff8880540400e0 (&type->s_umount_key#70){++++}-{4:4}, at: super_lock+0x27c/0x400 fs/super.c:120 #1: ffff88806bde80e8 (&sbi->s_lock#2){+.+.}-{4:4}, at: exfat_sync_fs+0xb0/0x160 fs/exfat/super.c:56 1 lock held by syz-executor/26986: 2 locks held by syz.0.4511/28226: 1 lock held by syz.3.4524/28308: #0: ffffffff8e941ab8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:297 [inline] #0: ffffffff8e941ab8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x381/0x830 kernel/rcu/tree_exp.h:976 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.12.0-syzkaller-09073-g9f16d5e6f220 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 nmi_cpu_backtrace+0x49c/0x4d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x198/0x320 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:223 [inline] watchdog+0xff4/0x1040 kernel/hung_task.c:379 kthread+0x2f2/0x390 kernel/kthread.c:389 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 16102 Comm: kworker/0:0 Not tainted 6.12.0-syzkaller-09073-g9f16d5e6f220 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Workqueue: events_power_efficient neigh_periodic_work RIP: 0010:__slab_alloc_node mm/slub.c:3961 [inline] RIP: 0010:slab_alloc_node mm/slub.c:4122 [inline] RIP: 0010:kmem_cache_alloc_node_noprof+0x1ed/0x320 mm/slub.c:4186 Code: ff 65 48 8b 04 25 28 00 00 00 48 3b 44 24 10 75 77 48 89 d8 48 83 c4 18 5b 41 5c 41 5d 41 5e 41 5f 5d e9 e1 ad fb 09 4c 89 ef <44> 89 ce 44 89 f2 4c 89 e1 45 89 f8 e8 42 55 00 00 44 8b 4c 24 04 RSP: 0018:ffffc900041479b0 EFLAGS: 00000246 RAX: ffff8880b8600000 RBX: 0000000000000000 RCX: 00000000000469f0 RDX: 0000000000fcc2a0 RSI: 00000000000000f0 RDI: ffff88801e686000 RBP: 0000000000000000 R08: ffffffff8988ff47 R09: 0000000000000820 R10: dffffc0000000000 R11: fffffbfff203a9ff R12: ffffffff8988ffa3 R13: ffff88801e686000 R14: 00000000ffffffff R15: 00000000000000f0 FS: 0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fbdcbf52440 CR3: 0000000053032000 CR4: 0000000000350ef0 Call Trace: __alloc_skb+0x1c3/0x440 net/core/skbuff.c:668 alloc_skb include/linux/skbuff.h:1323 [inline] nlmsg_new include/net/netlink.h:1018 [inline] __neigh_notify+0x81/0x140 net/core/neighbour.c:3454 neigh_cleanup_and_release+0xb7/0x2a0 net/core/neighbour.c:119 neigh_periodic_work+0xaf6/0xde0 net/core/neighbour.c:959 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xa65/0x1850 kernel/workqueue.c:3310 worker_thread+0x870/0xd30 kernel/workqueue.c:3391 kthread+0x2f2/0x390 kernel/kthread.c:389 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244