INFO: task syz.2.35:6132 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:syz.2.35 state:D stack:18840 pid:6132 tgid:6131 ppid:5817 task_flags:0x400140 flags:0x00004006 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 __closure_sync+0x163/0x220 lib/closure.c:146 bch2_wait_on_allocator fs/bcachefs/alloc_foreground.h:256 [inline] bch2_btree_update_start+0x1193/0x14c0 fs/bcachefs/btree_update_interior.c:1251 bch2_btree_split_leaf+0x13c/0x8f0 fs/bcachefs/btree_update_interior.c:1879 bch2_trans_commit_error+0x1a8/0x1100 fs/bcachefs/btree_trans_commit.c:904 __bch2_trans_commit+0x779c/0x8ae0 fs/bcachefs/btree_trans_commit.c:1069 bch2_trans_commit fs/bcachefs/btree_update.h:195 [inline] bch2_logged_op_start+0x170/0x280 fs/bcachefs/logged_ops.c:93 bch2_truncate+0x128/0x200 fs/bcachefs/io_misc.c:297 bchfs_truncate+0x7b7/0xcc0 fs/bcachefs/fs-io.c:509 notify_change+0xb33/0xe40 fs/attr.c:552 do_truncate+0x19a/0x220 fs/open.c:65 handle_truncate fs/namei.c:3501 [inline] do_open fs/namei.c:3884 [inline] path_openat+0x306c/0x3830 fs/namei.c:4039 do_filp_open+0x1fa/0x410 fs/namei.c:4066 do_sys_openat2+0x121/0x1c0 fs/open.c:1429 do_sys_open fs/open.c:1444 [inline] __do_sys_open fs/open.c:1452 [inline] __se_sys_open fs/open.c:1448 [inline] __x64_sys_open+0x11e/0x150 fs/open.c:1448 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: 0033:0x7ff8c6f8e969 RSP: 002b:00007ff8c7d90038 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 00007ff8c71b5fa0 RCX: 00007ff8c6f8e969 RDX: 0000000000000006 RSI: 000000000014927e RDI: 00002000000000c0 RBP: 00007ff8c7010ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007ff8c71b5fa0 R15: 00007ffd80efeca8 Showing all locks held in the system: 1 lock held by rcu_preempt/16: #0: ffff8880b89399d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:605 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 2 locks held by getty/5580: #0: ffff88814d3ed0a0 (&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 3 locks held by udevd/5834: 5 locks held by syz.2.35/6132: #0: ffff8880264a4420 (sb_writers#17){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:556 #1: ffff88805c959fa8 (&sb->s_type->i_mutex_key#26){++++}-{4:4}, at: inode_lock include/linux/fs.h:867 [inline] #1: ffff88805c959fa8 (&sb->s_type->i_mutex_key#26){++++}-{4:4}, at: do_truncate+0x186/0x220 fs/open.c:63 #2: ffff888053800a70 (&c->snapshot_create_lock){.+.+}-{4:4}, at: bch2_truncate+0xeb/0x200 fs/bcachefs/io_misc.c:295 #3: ffff888053804228 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:161 [inline] #3: ffff888053804228 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:253 [inline] #3: ffff888053804228 (&c->btree_trans_barrier){.+.+}-{0:0}, at: __bch2_trans_get+0x806/0xda0 fs/bcachefs/btree_iter.c:3385 #4: ffff888053826590 (&c->gc_lock){.+.+}-{4:4}, at: bch2_btree_update_start+0x68f/0x14c0 fs/bcachefs/btree_update_interior.c:1179 3 locks held by bch-copygc/loop/6149: 1 lock held by syz-executor/6399: #0: ffffffff8df41338 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:304 [inline] #0: ffffffff8df41338 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f4/0x730 kernel/rcu/tree_exp.h:998 2 locks held by syz.9.353/8866: 1 lock held by dhcpcd-run-hook/8892: ============================================= NMI backtrace for cpu 0 CPU: 0 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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 6149 Comm: bch-copygc/loop 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:spin_lock include/linux/spinlock.h:351 [inline] RIP: 0010:bch2_journal_pin_drop+0x2e/0x420 fs/bcachefs/journal_reclaim.c:384 Code: 55 41 57 41 56 41 55 41 54 53 48 83 ec 40 49 89 f7 49 89 fd 48 bb 00 00 00 00 00 fc ff df e8 29 f3 82 fd 4d 8d a5 98 10 00 00 <4c> 89 e7 e8 6a 9a 14 07 4d 8d 77 18 4c 89 f5 48 c1 ed 03 80 7c 1d RSP: 0018:ffffc9000ad4ec88 EFLAGS: 00000293 RAX: ffffffff843cdc37 RBX: dffffc0000000000 RCX: ffff888024a5bc00 RDX: 0000000000000000 RSI: ffff888053804548 RDI: ffff8880538495c0 RBP: ffffc9000ad4f058 R08: ffffc9000ad4ec87 R09: 1ffff920015a9d90 R10: dffffc0000000000 R11: fffff520015a9d91 R12: ffff88805384a658 R13: ffff8880538495c0 R14: ffff888051200000 R15: ffff888053804548 FS: 0000000000000000(0000) GS:ffff888126200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055e753b8a950 CR3: 0000000075dde000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: bch2_btree_write_buffer_flush_locked+0x35f9/0x45a0 fs/bcachefs/btree_write_buffer.c:494 bch2_btree_write_buffer_flush_nocheck_rw fs/bcachefs/btree_write_buffer.c:621 [inline] bch2_btree_write_buffer_tryflush+0x150/0x1a0 fs/bcachefs/btree_write_buffer.c:635 __bch2_move_data_phys+0x910/0x1b10 fs/bcachefs/move.c:786 bch2_evacuate_bucket+0x1b8/0x2b0 fs/bcachefs/move.c:946 bch2_copygc+0x323b/0x3cf0 fs/bcachefs/movinggc.c:240 bch2_copygc_thread+0x8c9/0xd40 fs/bcachefs/movinggc.c:405 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