INFO: task klogd:5222 blocked for more than 144 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:klogd state:D stack:24344 pid:5222 tgid:5222 ppid:1 task_flags:0x400100 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5360 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6964 __schedule_loop kernel/sched/core.c:7046 [inline] schedule+0x165/0x360 kernel/sched/core.c:7061 io_schedule+0x80/0xd0 kernel/sched/core.c:7906 migration_entry_wait_on_locked+0x648/0x940 mm/filemap.c:1452 migration_entry_wait+0x20b/0x250 mm/migrate.c:501 do_swap_page+0x455f/0x5950 mm/memory.c:4607 Showing all locks held in the system: 2 locks held by kworker/1:0/24: 1 lock held by khungtaskd/31: #0: ffffffff8e33cf20 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e33cf20 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8e33cf20 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 4 locks held by kworker/u8:3/50: 3 locks held by kworker/u8:4/61: 2 locks held by kswapd0/87: 3 locks held by kworker/u8:6/1098: 3 locks held by kworker/u8:7/1118: 1 lock held by klogd/5222: 2 locks held by udevd/5233: 2 locks held by getty/5623: #0: ffff8880300520a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000332e2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222 2 locks held by syz-executor/5860: 3 locks held by kworker/u8:12/7024: 3 locks held by kworker/u8:14/7298: 3 locks held by kworker/u8:17/7302: 2 locks held by syz-executor/7317: 2 locks held by syz-executor/7454: 3 locks held by kworker/1:7/7637: 2 locks held by syz-executor/7998: 3 locks held by syz-executor/8326: 3 locks held by kbnepd bnep0/9415: #0: ffffffff8f8cc710 (bnep_session_sem){++++}-{4:4}, at: bnep_session+0x2940/0x2b40 net/bluetooth/bnep/core.c:522 #1: ffffffff8f73f848 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #1: ffffffff8f73f848 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_dev_lock+0x257/0x2f0 net/core/dev.c:2142 #2: ffffffff8e3429b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline] #2: ffffffff8e3429b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730 kernel/rcu/tree_exp.h:957 5 locks held by dhcpcd-run-hook/9965: 2 locks held by syz-executor/10002: 4 locks held by kworker/0:9/10005: ============================================= 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 07/12/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/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+0xf60/0xfa0 kernel/hung_task.c:495 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x47c/0x820 arch/x86/kernel/process.c:148 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: 5233 Comm: udevd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:__lock_acquire+0xad3/0xd20 kernel/locking/lockdep.c:5245 Code: 01 00 00 4c 89 f6 89 ea 4c 89 f9 e8 17 38 00 00 85 c0 0f 84 e4 01 00 00 41 f6 46 22 10 75 2e 48 8b 1c 24 4c 89 bb 20 0b 00 00 <8b> 83 28 0b 00 00 ff c0 89 83 28 0b 00 00 83 f8 30 0f 83 64 01 00 RSP: 0018:ffffc900031070c8 EFLAGS: 00000046 RAX: 0000000000000001 RBX: ffff88807c54bc80 RCX: e37c92a613b5a100 RDX: 0000000000000000 RSI: ffff88807c54c7d8 RDI: ffff88807c54bc80 RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff8173bcb5 R10: ffffc90003107328 R11: fffff52000620e71 R12: 000000001df5900e R13: ffff88807c54c7b0 R14: ffff88807c54c7d8 R15: bb39787382043d4c FS: 00007f9192d6e880(0000) GS:ffff8881259f9000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd552520457 CR3: 000000007cbae000 CR4: 00000000003526f0 DR0: 0000000002000000 DR1: 0000000000000003 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:841 [inline] class_rcu_constructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479 __unwind_start+0x5b9/0x760 arch/x86/kernel/unwind_orc.c:758