INFO: task syz-executor:5769 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:20936 pid:5769 ppid:1 flags:0x00004002 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 wb_wait_for_completion+0x173/0x2a0 fs/fs-writeback.c:192 sync_inodes_sb+0x1c9/0xa10 fs/fs-writeback.c:2778 sync_filesystem+0x171/0x220 fs/sync.c:64 generic_shutdown_super+0x6f/0x2b0 fs/super.c:666 kill_block_super+0x44/0x90 fs/super.c:1660 deactivate_locked_super+0x97/0x100 fs/super.c:481 cleanup_mnt+0x43b/0x4d0 fs/namespace.c:1259 task_work_run+0x1d4/0x260 kernel/task_work.c:245 exit_task_work include/linux/task_work.h:43 [inline] do_exit+0x95a/0x2460 kernel/exit.c:883 do_group_exit+0x21b/0x2d0 kernel/exit.c:1024 __do_sys_exit_group kernel/exit.c:1035 [inline] __se_sys_exit_group kernel/exit.c:1033 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1033 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: 0033:0x7fab5ed9c799 RSP: 002b:00007fff8bd09688 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007fab5ee31ff0 RCX: 00007fab5ed9c799 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001 RBP: 000000000000000c R08: 0000000000000000 R09: 00007fab5ee31f90 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff8bd0a940 R13: 00007fab5ee31f90 R14: 000055559499c4e8 R15: 00007fff8bd0ba10 Showing all locks held in the system: 1 lock held by rcu_tasks_trace/15: #0: ffffffff8d132d90 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0xadb/0xdb0 kernel/rcu/tasks.h:607 1 lock held by khungtaskd/29: #0: ffffffff8d132060 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #0: ffffffff8d132060 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #0: ffffffff8d132060 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633 2 locks held by kworker/u4:6/1135: #0: ffff888018aa8d38 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2628 [inline] #0: ffff888018aa8d38 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2730 #1: ffffc90004b0fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2628 [inline] #1: ffffc90004b0fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2730 2 locks held by kworker/u4:10/1336: 2 locks held by getty/5534: #0: ffff8880322520a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000328b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x433/0x1390 drivers/tty/n_tty.c:2217 2 locks held by syz-executor/5769: #0: ffff888025a320e0 (&type->s_umount_key#72){+.+.}-{3:3}, at: __super_lock fs/super.c:56 [inline] #0: ffff888025a320e0 (&type->s_umount_key#72){+.+.}-{3:3}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff888025a320e0 (&type->s_umount_key#72){+.+.}-{3:3}, at: deactivate_super+0xa4/0xe0 fs/super.c:513 #1: ffff888021dfa7d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:364 [inline] #1: ffff888021dfa7d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x1ad/0xa10 fs/fs-writeback.c:2776 4 locks held by segctord/6202: 2 locks held by kworker/u4:18/7042: #0: ffff8880b8e3c018 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:559 #1: ffffc90005a3fd00 ((work_completion)(&(&bat_priv->nc.work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2628 [inline] #1: ffffc90005a3fd00 ((work_completion)(&(&bat_priv->nc.work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2730 1 lock held by syz-executor/7971: ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 29 Comm: khungtaskd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 6202 Comm: segctord Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:arch_atomic_read arch/x86/include/asm/atomic.h:23 [inline] RIP: 0010:raw_atomic_read include/linux/atomic/atomic-arch-fallback.h:444 [inline] RIP: 0010:rcu_dynticks_curr_cpu_in_eqs include/linux/context_tracking.h:122 [inline] RIP: 0010:rcu_is_watching+0x55/0xb0 kernel/rcu/tree.c:700 Code: 4a a7 8c 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 74 08 4c 89 f7 e8 2c 69 6e 00 48 c7 c3 28 6b 03 00 49 03 1e 48 89 d8 48 c1 e8 03 <42> 0f b6 04 38 84 c0 75 2f 8b 03 65 ff 0d 81 d3 92 7e 74 0c 83 e0 RSP: 0018:ffffc9000bd5f340 EFLAGS: 00000a06 RAX: 1ffff110171e6d65 RBX: ffff8880b8f36b28 RCX: b241aaad7eb7f400 RDX: 0000000000000000 RSI: ffffffff8b1c8580 RDI: ffffffff8b1c8540 RBP: ffffc9000bd5f478 R08: ffffffff8e8aeeef R09: 1ffffffff1d15ddd R10: dffffc0000000000 R11: fffffbfff1d15dde R12: 1ffff920017abe78 R13: ffff8880202b6660 R14: ffffffff8ca74a38 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f3aae5e82f8 CR3: 000000001a362000 CR4: 00000000003506e0 Call Trace: trace_lock_acquire include/trace/events/lock.h:24 [inline] lock_acquire+0xc6/0x420 kernel/locking/lockdep.c:5725 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] __find_get_block_slow fs/buffer.c:207 [inline] __find_get_block+0x3ab/0xeb0 fs/buffer.c:1413 __getblk_slow fs/buffer.c:1141 [inline] __getblk_gfp+0x169/0x660 fs/buffer.c:1439 sb_getblk include/linux/buffer_head.h:344 [inline] nilfs_segbuf_extend_segsum+0xcf/0x360 fs/nilfs2/segbuf.c:99 nilfs_segbuf_reset+0x37/0x140 fs/nilfs2/segbuf.c:135 nilfs_segctor_reset_segment_buffer fs/nilfs2/segment.c:421 [inline] nilfs_segctor_collect fs/nilfs2/segment.c:1531 [inline] nilfs_segctor_do_construct+0x129f/0x68a0 fs/nilfs2/segment.c:2091 nilfs_segctor_construct+0x17b/0x690 fs/nilfs2/segment.c:2454 nilfs_segctor_thread_construct fs/nilfs2/segment.c:2562 [inline] nilfs_segctor_thread+0x536/0x10d0 fs/nilfs2/segment.c:2646 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