INFO: task bch-reclaim/loo:6336 blocked for more than 143 seconds. Not tainted 6.15.0-rc5-syzkaller-00123-g2c89c1b655c0 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:bch-reclaim/loo state:D stack:26584 pid:6336 tgid:6336 ppid:2 task_flags:0x200840 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x168f/0x4c70 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0x165/0x360 kernel/sched/core.c:6860 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6917 __mutex_lock_common kernel/locking/mutex.c:678 [inline] __mutex_lock+0x724/0xe80 kernel/locking/mutex.c:746 btree_write_buffer_flush_seq+0x1829/0x19a0 fs/bcachefs/btree_write_buffer.c:569 bch2_btree_write_buffer_journal_flush+0x69/0xb0 fs/bcachefs/btree_write_buffer.c:586 journal_flush_pins+0x8e0/0xe90 fs/bcachefs/journal_reclaim.c:592 __bch2_journal_reclaim+0x781/0xd10 fs/bcachefs/journal_reclaim.c:723 bch2_journal_reclaim_thread+0x177/0x4f0 fs/bcachefs/journal_reclaim.c:765 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6764 4 locks held by kworker/u8:2/36: 5 locks held by kworker/u8:5/2889: 2 locks held by getty/5587: #0: ffff888030a640a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90002ffe2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222 2 locks held by syz-executor/5819: #0: ffff88802a6220e0 (&type->s_umount_key#62){++++}-{4:4}, at: __super_lock fs/super.c:56 [inline] #0: ffff88802a6220e0 (&type->s_umount_key#62){++++}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff88802a6220e0 (&type->s_umount_key#62){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:505 #1: ffff88805bb80278 (&c->state_lock){++++}-{4:4}, at: __bch2_fs_stop+0xfe/0x5a0 fs/bcachefs/super.c:622 1 lock held by udevd/5820: 3 locks held by bch-reclaim/loo/6336: #0: ffff88805bbcad28 (&j->reclaim_lock){+.+.}-{4:4}, at: bch2_journal_reclaim_thread+0x16b/0x4f0 fs/bcachefs/journal_reclaim.c:764 #1: ffff88805bb84228 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:161 [inline] #1: ffff88805bb84228 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:253 [inline] #1: ffff88805bb84228 (&c->btree_trans_barrier){.+.+}-{0:0}, at: __bch2_trans_get+0x806/0xda0 fs/bcachefs/btree_iter.c:3385 #2: ffff88805bb845d0 (&wb->flushing.lock){+.+.}-{4:4}, at: btree_write_buffer_flush_seq+0x1829/0x19a0 fs/bcachefs/btree_write_buffer.c:569 3 locks held by bch-copygc/loop/6337: #0: ffff88805bb845d0 (&wb->flushing.lock){+.+.}-{4:4}, at: bch2_btree_write_buffer_flush_nocheck_rw fs/bcachefs/btree_write_buffer.c:620 [inline] #0: ffff88805bb845d0 (&wb->flushing.lock){+.+.}-{4:4}, at: bch2_btree_write_buffer_tryflush+0x130/0x1a0 fs/bcachefs/btree_write_buffer.c:635 #1: ffff88805bb84228 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:161 [inline] #1: ffff88805bb84228 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:253 [inline] #1: ffff88805bb84228 (&c->btree_trans_barrier){.+.+}-{0:0}, at: bch2_trans_srcu_lock+0xaf/0x220 fs/bcachefs/btree_iter.c:3202 #2: ffff88805bba6590 (&c->gc_lock){++++}-{4:4}, at: bch2_btree_update_start+0x68f/0x14c0 fs/bcachefs/btree_update_interior.c:1179 1 lock held by syz.6.81/6660: #0: ffff88802a6220e0 (&type->s_umount_key#62){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88802a6220e0 (&type->s_umount_key#62){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:120 1 lock held by syz.7.111/7024: #0: ffff88802a6220e0 (&type->s_umount_key#62){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88802a6220e0 (&type->s_umount_key#62){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:120 1 lock held by syz.7.111/7087: #0: ffff88802a6220e0 (&type->s_umount_key#62){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88802a6220e0 (&type->s_umount_key#62){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:120 1 lock held by syz-executor/7641: #0: ffffffff8df41338 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:336 [inline] #0: ffffffff8df41338 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b7/0x730 kernel/rcu/tree_exp.h:998 2 locks held by syz.5.295/9041: 1 lock held by syz.0.294/9052: 1 lock held by sed/9067: #0: ffff8880b88399d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:605 2 locks held by dhcpcd-run-hook/9071: ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-rc5-syzkaller-00123-g2c89c1b655c0 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/29/2025 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:274 [inline] watchdog+0xfee/0x1030 kernel/hung_task.c:437 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153 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: 5190 Comm: udevd Not tainted 6.15.0-rc5-syzkaller-00123-g2c89c1b655c0 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/29/2025 RIP: 0010:trace_lock_release include/trace/events/lock.h:69 [inline] RIP: 0010:lock_release+0x44/0x3e0 kernel/locking/lockdep.c:5877 Code: 8b 05 70 d2 d3 10 48 89 44 24 28 0f 1f 44 00 00 65 8b 05 73 d2 d3 10 83 f8 08 0f 83 9a 02 00 00 89 c0 48 0f a3 05 9c 79 df 0d <73> 16 e8 c5 c8 08 00 84 c0 75 0d f6 05 13 77 c9 0d 01 0f 84 ad 02 RSP: 0018:ffffc900030e7c38 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffff888063566620 RCX: 517bf40155535500 RDX: 0000000000000000 RSI: ffffffff8208e790 RDI: ffff888069f1dbe0 RBP: 1ffff1100d2ac4f0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff8208e790 R12: ffff888063566620 R13: ffffffff8208e790 R14: ffff888069f1dbe0 R15: 00007ffcb1578ef0 FS: 00007fe13806e880(0000) GS:ffff888126100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055558514a608 CR3: 0000000069be2000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: strncpy_from_user+0x31/0x290 lib/strncpy_from_user.c:117 getname_flags+0xf3/0x540 fs/namei.c:157 getname include/linux/fs.h:2852 [inline] getname_maybe_null include/linux/fs.h:2859 [inline] vfs_fstatat+0x43/0x160 fs/stat.c:367 __do_sys_newfstatat fs/stat.c:536 [inline] __se_sys_newfstatat fs/stat.c:530 [inline] __x64_sys_newfstatat+0x11c/0x1a0 fs/stat.c:530 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe137911b0a Code: 48 8b 15 f1 f2 0d 00 f7 d8 64 89 02 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 41 89 ca b8 06 01 00 00 0f 05 <3d> 00 f0 ff ff 77 07 31 c0 c3 0f 1f 40 00 48 8b 15 b9 f2 0d 00 f7 RSP: 002b:00007ffcb1578a58 EFLAGS: 00000246 ORIG_RAX: 0000000000000106 RAX: ffffffffffffffda RBX: 00007ffcb1578ef0 RCX: 00007fe137911b0a RDX: 00007ffcb1578a60 RSI: 00007ffcb1578ef0 RDI: 00000000ffffff9c RBP: 000055a092e72910 R08: 0000000000000000 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffcb1578af0 R13: 0000000000000100 R14: 000055a05f477be0 R15: 00007ffcb1579570