INFO: task kworker/u8:5:997 blocked for more than 143 seconds. Not tainted 6.16.0-rc1-next-20250613-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u8:5 state:D stack:20056 pid:997 tgid:997 ppid:2 task_flags:0x4248160 flags:0x00004000 Workqueue: writeback wb_workfn (flush-bcachefs-67) Call Trace: context_switch kernel/sched/core.c:5396 [inline] __schedule+0x16f5/0x4d00 kernel/sched/core.c:6785 __schedule_loop kernel/sched/core.c:6863 [inline] schedule+0x165/0x360 kernel/sched/core.c:6878 __closure_sync+0x163/0x220 lib/closure.c:146 bch2_wait_on_allocator fs/bcachefs/alloc_foreground.h:315 [inline] __bch2_write+0x31ef/0x3900 fs/bcachefs/io_write.c:1593 closure_queue include/linux/closure.h:270 [inline] closure_call include/linux/closure.h:432 [inline] bch2_writepage_do_io fs/bcachefs/fs-io-buffered.c:486 [inline] __bch2_writepage+0x1536/0x2790 fs/bcachefs/fs-io-buffered.c:633 write_cache_pages+0x64/0x100 mm/page-writeback.c:2614 bch2_writepages+0xf9/0x2d0 fs/bcachefs/fs-io-buffered.c:666 do_writepages+0x32b/0x550 mm/page-writeback.c:2636 __writeback_single_inode+0x145/0xff0 fs/fs-writeback.c:1680 writeback_sb_inodes+0x6c7/0x1010 fs/fs-writeback.c:1976 __writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2047 wb_writeback+0x44f/0xaf0 fs/fs-writeback.c:2158 wb_check_old_data_flush fs/fs-writeback.c:2262 [inline] wb_do_writeback fs/fs-writeback.c:2315 [inline] wb_workfn+0xaef/0xef0 fs/fs-writeback.c:2343 process_one_work kernel/workqueue.c:3235 [inline] process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3318 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3399 kthread+0x711/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 INFO: task syz.6.4627:25656 blocked for more than 144 seconds. Not tainted 6.16.0-rc1-next-20250613-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.6.4627 state:D stack:17832 pid:25656 tgid:25655 ppid:24472 task_flags:0x440140 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5396 [inline] __schedule+0x16f5/0x4d00 kernel/sched/core.c:6785 __schedule_loop kernel/sched/core.c:6863 [inline] schedule+0x165/0x360 kernel/sched/core.c:6878 __closure_sync+0x163/0x220 lib/closure.c:146 bch2_wait_on_allocator fs/bcachefs/alloc_foreground.h:315 [inline] __bch2_write+0x31ef/0x3900 fs/bcachefs/io_write.c:1593 closure_queue include/linux/closure.h:270 [inline] closure_call include/linux/closure.h:432 [inline] bch2_writepage_do_io fs/bcachefs/fs-io-buffered.c:486 [inline] __bch2_writepage+0x1536/0x2790 fs/bcachefs/fs-io-buffered.c:633 write_cache_pages+0x64/0x100 mm/page-writeback.c:2614 bch2_writepages+0xf9/0x2d0 fs/bcachefs/fs-io-buffered.c:666 do_writepages+0x32b/0x550 mm/page-writeback.c:2636 filemap_fdatawrite_wbc mm/filemap.c:386 [inline] __filemap_fdatawrite_range mm/filemap.c:419 [inline] file_write_and_wait_range+0x23e/0x340 mm/filemap.c:794 bch2_fsync+0x127/0x330 fs/bcachefs/fs-io.c:245 generic_write_sync include/linux/fs.h:3033 [inline] bch2_write_iter+0x2822/0x2b90 fs/bcachefs/fs-io-buffered.c:1089 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x54b/0xa90 fs/read_write.c:686 ksys_write+0x145/0x250 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7effbed8e929 RSP: 002b:00007effbfc95038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007effbefb5fa0 RCX: 00007effbed8e929 RDX: 000000000208e24b RSI: 0000200000000100 RDI: 0000000000000005 RBP: 00007effbee10b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007effbefb5fa0 R15: 00007ffe83fc9a68 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8e13ee20 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e13ee20 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8e13ee20 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6770 3 locks held by kworker/u8:5/997: #0: ffff888140add148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3210 [inline] #0: ffff888140add148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3318 #1: ffffc90003887bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline] #1: ffffc90003887bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3318 #2: ffff88806fde00e0 (&type->s_umount_key#101){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:563 2 locks held by getty/5602: #0: ffff88814c24e0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90002fee2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222 1 lock held by syz-executor/5825: #0: ffff8880b863b918 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:606 2 locks held by syz.6.4627/25656: #0: ffff888077a9d278 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x247/0x320 fs/file.c:1213 #1: ffff88806fde0428 (sb_writers#26){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3098 [inline] #1: ffff88806fde0428 (sb_writers#26){.+.+}-{0:0}, at: vfs_write+0x211/0xa90 fs/read_write.c:682 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.16.0-rc1-next-20250613-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 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:158 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:307 [inline] watchdog+0xfee/0x1030 kernel/hung_task.c:470 kthread+0x711/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3f9/0x770 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: 0 Comm: swapper/0 Not tainted 6.16.0-rc1-next-20250613-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82 Code: 03 d4 02 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d c3 4f 1f 00 f3 0f 1e fa fb f4 d8 d3 02 00 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffffff8de07d80 EFLAGS: 000002c2 RAX: e1833ca067bec000 RBX: ffffffff81975df8 RCX: e1833ca067bec000 RDX: 0000000000000001 RSI: ffffffff8d98bf73 RDI: ffffffff8be2ea60 RBP: ffffffff8de07ea8 R08: ffff8880b8632f5b R09: 1ffff110170c65eb R10: dffffc0000000000 R11: ffffed10170c65ec R12: ffffffff8fa157f0 R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1bd2a50 FS: 0000000000000000(0000) GS:ffff888125c41000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f8bc5580ab8 CR3: 000000007c972000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000097 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:749 default_idle_call+0x74/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:190 [inline] do_idle+0x1e8/0x510 kernel/sched/idle.c:330 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428 rest_init+0x2de/0x300 init/main.c:745 start_kernel+0x47d/0x500 init/main.c:1102 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:307 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:288 common_startup_64+0x13e/0x147