INFO: task bch-reclaim/loo:9372 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:bch-reclaim/loo state:D stack:26664 pid:9372 tgid:9372 ppid:2 task_flags:0x200840 flags:0x00004000 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 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7118 __mutex_lock_common kernel/locking/mutex.c:676 [inline] __mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:760 btree_write_buffer_flush_seq+0x18bd/0x1a40 fs/bcachefs/btree_write_buffer.c:571 bch2_btree_write_buffer_journal_flush+0x69/0xb0 fs/bcachefs/btree_write_buffer.c:588 journal_flush_pins+0x8e3/0xe90 fs/bcachefs/journal_reclaim.c:604 __bch2_journal_reclaim+0x910/0xed0 fs/bcachefs/journal_reclaim.c:732 bch2_journal_reclaim_thread+0x177/0x4f0 fs/bcachefs/journal_reclaim.c:774 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Showing all locks held in the system: 2 locks held by kworker/u8:0/12: 1 lock held by khungtaskd/31: #0: ffffffff8e33c820 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e33c820 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8e33c820 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 3 locks held by kworker/u8:4/60: 2 locks held by getty/5626: #0: ffff88814dd980a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900036be2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222 5 locks held by syz-executor/5866: #0: ffff88804fa6a0e0 (&type->s_umount_key#83){++++}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff88804fa6a0e0 (&type->s_umount_key#83){++++}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff88804fa6a0e0 (&type->s_umount_key#83){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:505 #1: ffff88803b680278 (&c->state_lock){++++}-{4:4}, at: __bch2_fs_stop+0xf8/0x900 fs/bcachefs/super.c:676 #2: ffff88803b684740 (&wb->flushing.lock){+.+.}-{4:4}, at: btree_write_buffer_flush_seq+0x18bd/0x1a40 fs/bcachefs/btree_write_buffer.c:571 #3: ffff88803b684398 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:161 [inline] #3: ffff88803b684398 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:253 [inline] #3: ffff88803b684398 (&c->btree_trans_barrier){.+.+}-{0:0}, at: bch2_trans_srcu_lock+0xaf/0x220 fs/bcachefs/btree_iter.c:3299 #4: ffff88803b6a6710 (&c->gc_lock){++++}-{4:4}, at: bch2_btree_update_start+0x542/0x1de0 fs/bcachefs/btree_update_interior.c:1211 1 lock held by udevd/5996: 2 locks held by syz.5.540/8806: #0: ffff888076ab87c8 (&sb->s_type->i_mutex_key#11){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:980 [inline] #0: ffff888076ab87c8 (&sb->s_type->i_mutex_key#11){+.+.}-{4:4}, at: __sock_release net/socket.c:648 [inline] #0: ffff888076ab87c8 (&sb->s_type->i_mutex_key#11){+.+.}-{4:4}, at: sock_close+0x9b/0x240 net/socket.c:1442 #1: ffff888020ea0260 (sk_lock-AF_CAN){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1676 [inline] #1: ffff888020ea0260 (sk_lock-AF_CAN){+.+.}-{0:0}, at: j1939_sk_release+0xb3/0x7c0 net/can/j1939/socket.c:637 3 locks held by bch-reclaim/loo/9372: #0: ffff88803b6caf68 (&j->reclaim_lock){+.+.}-{4:4}, at: bch2_journal_reclaim_thread+0x16b/0x4f0 fs/bcachefs/journal_reclaim.c:773 #1: ffff88803b684398 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:161 [inline] #1: ffff88803b684398 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:253 [inline] #1: ffff88803b684398 (&c->btree_trans_barrier){.+.+}-{0:0}, at: __bch2_trans_get+0x7f4/0xd80 fs/bcachefs/btree_iter.c:3505 #2: ffff88803b684740 (&wb->flushing.lock){+.+.}-{4:4}, at: btree_write_buffer_flush_seq+0x18bd/0x1a40 fs/bcachefs/btree_write_buffer.c:571 1 lock held by syz.6.873/10264: #0: ffff88804fa6a0e0 (&type->s_umount_key#83){++++}-{4:4}, at: __super_lock fs/super.c:59 [inline] #0: ffff88804fa6a0e0 (&type->s_umount_key#83){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:121 2 locks held by syz.7.1134/11495: 2 locks held by syz.2.1133/11499: 2 locks held by syz.0.1136/11504: 5 locks held by syz.9.1137/11508: 1 lock held by syz.9.1137/11509: ============================================= 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 08/18/2025 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+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 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: 11495 Comm: syz.7.1134 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:const_folio_flags include/linux/page-flags.h:354 [inline] RIP: 0010:folio_test_dirty include/linux/page-flags.h:559 [inline] RIP: 0010:noop_dirty_folio+0x23/0x130 mm/page-writeback.c:2636 Code: 90 90 90 90 90 90 90 f3 0f 1e fa 41 57 41 56 41 55 41 54 53 48 89 f3 49 bf 00 00 00 00 00 fc ff df e8 61 2e c6 ff 4c 8d 73 08 <4d> 89 f4 49 c1 ec 03 43 80 3c 3c 00 74 08 4c 89 f7 e8 57 b0 2a 00 RSP: 0018:ffffc9000393fa98 EFLAGS: 00000246 RAX: ffffffff81f98d0f RBX: ffffea0000fef300 RCX: 0000000000080000 RDX: ffffc900122e2000 RSI: 000000000007ffff RDI: 0000000000080000 RBP: dffffc0000000000 R08: ffffea0000fef307 R09: 1ffffd40001fde60 R10: dffffc0000000000 R11: ffffffff81f98cf0 R12: 0000000000001000 R13: 0000000000001000 R14: ffffea0000fef308 R15: dffffc0000000000 FS: 00007f98586ee6c0(0000) GS:ffff8881259e8000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f984e3ff000 CR3: 00000000627a4000 CR4: 00000000003526f0 Call Trace: shmem_write_end+0x424/0x5d0 mm/shmem.c:3335 generic_perform_write+0x62a/0x900 mm/filemap.c:4230 shmem_file_write_iter+0xf8/0x120 mm/shmem.c:3478 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x5c9/0xb30 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/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f985778d65f Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 f9 92 02 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 4c 93 02 00 48 RSP: 002b:00007f98586eddf0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000001000000 RCX: 00007f985778d65f RDX: 0000000001000000 RSI: 00007f984d400000 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000009687 R10: 000020000001c302 R11: 0000000000000293 R12: 0000000000000003 R13: 00007f98586edef0 R14: 00007f98586edeb0 R15: 00007f984d400000