INFO: task syz.7.2974:16219 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.7.2974 state:D stack:27376 pid:16219 ppid:10599 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1553/0x45a0 kernel/sched/core.c:6700 schedule+0xbd/0x170 kernel/sched/core.c:6774 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6833 __mutex_lock_common kernel/locking/mutex.c:679 [inline] __mutex_lock+0x6a9/0xcc0 kernel/locking/mutex.c:747 sync_bdevs+0x1af/0x330 block/bdev.c:1076 ksys_sync+0xc6/0x170 fs/sync.c:105 __ia32_sys_sync+0xe/0x20 fs/sync.c:113 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7ff5c019c819 RSP: 002b:00007ff5c0fb0028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 00007ff5c0415fa0 RCX: 00007ff5c019c819 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007ff5c0415fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ff5c0416038 R14: 00007ff5c0415fa0 R15: 00007ffca5c6ed48 Showing all locks held in the system: 1 lock held by khungtaskd/29: #0: ffffffff8d1320a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #0: ffffffff8d1320a0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #0: ffffffff8d1320a0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633 1 lock held by udevd/5137: 1 lock held by dhcpcd/5432: 2 locks held by getty/5529: #0: ffff88814c1a90a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000326e2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x433/0x1390 drivers/tty/n_tty.c:2217 1 lock held by udevd/5755: #0: ffff8881413784c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x121/0x600 block/bdev.c:805 1 lock held by syz-executor/14167: #0: ffffffff8d137a78 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:324 [inline] #0: ffffffff8d137a78 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3da/0x880 kernel/rcu/tree_exp.h:1004 1 lock held by syz.7.2974/16219: #0: ffff8881413784c8 (&disk->open_mutex){+.+.}-{3:3}, at: sync_bdevs+0x1af/0x330 block/bdev.c:1076 1 lock held by syz-executor/16603: #0: ffff88805bd4a0e0 (&type->s_umount_key#54){++++}-{3:3}, at: __super_lock fs/super.c:56 [inline] #0: ffff88805bd4a0e0 (&type->s_umount_key#54){++++}-{3:3}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff88805bd4a0e0 (&type->s_umount_key#54){++++}-{3:3}, at: deactivate_super+0xa4/0xe0 fs/super.c:513 2 locks held by syz.4.3735/19658: 2 locks held by syz.8.3742/19660: 2 locks held by dhcpcd-run-hook/19670: ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 29 Comm: khungtaskd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call Trace: dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106 nmi_cpu_backtrace+0x3a6/0x3e0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x2f0 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline] watchdog+0xf3d/0xf80 kernel/hung_task.c:379 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 12 Comm: kworker/u4:1 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Workqueue: events_unbound nsim_dev_trap_report_work RIP: 0010:__orc_find arch/x86/kernel/unwind_orc.c:99 [inline] RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:227 [inline] RIP: 0010:unwind_next_frame+0x4d4/0x2970 arch/x86/kernel/unwind_orc.c:494 Code: 4d 01 fd 4c 89 ef 4c 89 f6 e8 98 e7 4b 00 49 8d 47 04 4d 39 f5 4c 0f 46 e0 49 8d 47 fc 48 0f 47 d8 49 0f 46 ef 49 39 dc 77 28 67 e5 4b 00 48 ba 00 00 00 00 00 fc ff df eb 97 44 89 f9 80 e1 RSP: 0018:ffffc900001174d8 EFLAGS: 00000293 RAX: ffffffff8ea2fe38 RBX: ffffffff8ea2fe54 RCX: ffff88801be4da00 RDX: 0000000000000000 RSI: ffffffff81df2dad RDI: ffffffff81df2d65 RBP: ffffffff8ea2fe3c R08: ffffc90000117670 R09: 0000000000000000 R10: 0000000000000004 R11: 0000000000000000 R12: ffffffff8ea2fe40 R13: ffffffff81df2d65 R14: ffffffff81df2dad R15: ffffffff8ea2fe3c FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f29b9eb5e9c CR3: 000000007f20c000 CR4: 00000000003506f0 Call Trace: arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4e/0x70 mm/kasan/common.c:53 kasan_save_free_info+0x2e/0x50 mm/kasan/generic.c:522 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:237 kasan_slab_free include/linux/kasan.h:164 [inline] slab_free_hook mm/slub.c:1811 [inline] slab_free_freelist_hook+0x130/0x1a0 mm/slub.c:1837 slab_free mm/slub.c:3830 [inline] __kmem_cache_free+0xba/0x1e0 mm/slub.c:3843 skb_kfree_head net/core/skbuff.c:949 [inline] skb_free_head net/core/skbuff.c:961 [inline] skb_release_data+0x634/0x800 net/core/skbuff.c:991 skb_release_all net/core/skbuff.c:1057 [inline] __kfree_skb net/core/skbuff.c:1071 [inline] consume_skb+0xb2/0x110 net/core/skbuff.c:1287 nsim_dev_trap_report drivers/net/netdevsim/dev.c:821 [inline] nsim_dev_trap_report_work+0x76f/0xb00 drivers/net/netdevsim/dev.c:851 process_one_work kernel/workqueue.c:2653 [inline] process_scheduled_works+0xa5d/0x15d0 kernel/workqueue.c:2730 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2811 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293