INFO: task syz.3.4:5336 blocked for more than 143 seconds. Not tainted 6.11.0-syzkaller-11728-gad46e8f95e93 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.4 state:D stack:27424 pid:5336 tgid:5298 ppid:5215 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:5315 [inline] __schedule+0x1843/0x4ae0 kernel/sched/core.c:6675 __schedule_loop kernel/sched/core.c:6752 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6767 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6824 __mutex_lock_common kernel/locking/mutex.c:684 [inline] __mutex_lock+0x6a7/0xd70 kernel/locking/mutex.c:752 fdget_pos+0x24e/0x320 fs/file.c:1187 ksys_write+0x7e/0x2b0 fs/read_write.c:727 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc31b37dff9 RSP: 002b:00007fc31adde038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fc31b536058 RCX: 00007fc31b37dff9 RDX: 0000000000000118 RSI: 0000000020000280 RDI: 0000000000000005 RBP: 00007fc31b3f0296 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000001 R14: 00007fc31b536058 R15: 00007fff03b2ebe8 Showing all locks held in the system: 2 locks held by kworker/u8:0/11: #0: ffff88801ac89148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline] #0: ffff88801ac89148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1850 kernel/workqueue.c:3310 #1: ffffc90000107d00 ((reaper_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline] #1: ffffc90000107d00 ((reaper_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310 1 lock held by khungtaskd/30: #0: ffffffff8e937da0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #0: ffffffff8e937da0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff8e937da0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6701 2 locks held by kworker/u8:8/2973: #0: ffff88801ac89148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline] #0: ffff88801ac89148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1850 kernel/workqueue.c:3310 #1: ffffc9000a4b7d00 (connector_reaper_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline] #1: ffffc9000a4b7d00 (connector_reaper_work){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310 2 locks held by getty/4975: #0: ffff8880314a00a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900031332f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6a6/0x1e00 drivers/tty/n_tty.c:2211 1 lock held by udevd/5209: #0: ffff8880b873ea58 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:593 3 locks held by kworker/0:4/5267: 2 locks held by syz.3.4/5299: #0: ffff88807552ad38 (&f->f_pos_lock){+.+.}-{3:3}, at: fdget_pos+0x24e/0x320 fs/file.c:1187 #1: ffff88807b28a420 (sb_writers#16){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2931 [inline] #1: ffff88807b28a420 (sb_writers#16){.+.+}-{0:0}, at: vfs_write+0x224/0xc90 fs/read_write.c:679 1 lock held by syz.3.4/5336: #0: ffff88807552ad38 (&f->f_pos_lock){+.+.}-{3:3}, at: fdget_pos+0x24e/0x320 fs/file.c:1187 2 locks held by bch-copygc/loop/5324: 1 lock held by syz-executor/6223: #0: ffffffff8e93d338 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:297 [inline] #0: ffffffff8e93d338 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x381/0x830 kernel/rcu/tree_exp.h:976 2 locks held by syz.0.176/6789: #0: ffff88807553c0e0 (&type->s_umount_key#68/1){+.+.}-{3:3}, at: alloc_super+0x221/0x9d0 fs/super.c:344 #1: ffffffff8e93d200 (rcu_state.barrier_mutex){+.+.}-{3:3}, at: rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:4561 2 locks held by syz.4.177/6794: 2 locks held by syz.2.178/6798: #0: ffff88807db9c0e0 (&type->s_umount_key#73/1){+.+.}-{3:3}, at: alloc_super+0x221/0x9d0 fs/super.c:344 #1: ffffffff8e93d338 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:329 [inline] #1: ffffffff8e93d338 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x451/0x830 kernel/rcu/tree_exp.h:976 2 locks held by syz.2.178/6802: ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.11.0-syzkaller-11728-gad46e8f95e93 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 nmi_cpu_backtrace+0x49c/0x4d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x198/0x320 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:223 [inline] watchdog+0xff4/0x1040 kernel/hung_task.c:379 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 5324 Comm: bch-copygc/loop Not tainted 6.11.0-syzkaller-11728-gad46e8f95e93 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 RIP: 0010:check_preemption_disabled+0x60/0x120 lib/smp_processor_id.c:19 Code: 00 48 3b 44 24 08 0f 85 ce 00 00 00 89 d8 48 83 c4 10 5b 41 5c 41 5e 41 5f c3 cc cc cc cc 48 c7 04 24 00 00 00 00 9c 8f 04 24 04 24 00 02 00 00 74 c5 49 89 f6 49 89 ff 65 4c 8b 24 25 80 d7 RSP: 0018:ffffc900041a6c68 EFLAGS: 00000046 RAX: 0000000080000000 RBX: 0000000000000000 RCX: ffffffff93dff6d0 RDX: 0000000000000001 RSI: ffffffff8c0adb40 RDI: ffffffff8c601fe0 RBP: ffffc900041a6df8 R08: 0000000000000001 R09: 0000000000000000 R10: dffffc0000000000 R11: fffffbfff20376ce R12: 1ffff92000834d9c R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000246 FS: 0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f83dc1bd440 CR3: 000000000e734000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lockdep_recursion_finish kernel/locking/lockdep.c:467 [inline] lock_acquire+0x1fd/0x550 kernel/locking/lockdep.c:5824 six_trylock_ip fs/bcachefs/six.c:297 [inline] six_relock_ip+0xda/0x1a0 fs/bcachefs/six.c:315 six_relock_type fs/bcachefs/six.h:289 [inline] __bch2_btree_node_relock+0x139/0x940 fs/bcachefs/btree_locking.c:497 btree_path_good_node fs/bcachefs/btree_iter.c:1057 [inline] __btree_path_up_until_good_node+0x111/0xb40 fs/bcachefs/btree_iter.c:1084 btree_path_up_until_good_node fs/bcachefs/btree_iter.c:1107 [inline] __bch2_btree_path_set_pos+0x9d5/0x1710 fs/bcachefs/btree_iter.c:1275 bch2_btree_path_set_pos fs/bcachefs/btree_iter.h:229 [inline] __bch2_btree_iter_peek fs/bcachefs/btree_iter.c:2193 [inline] bch2_btree_iter_peek_upto+0xa40/0x6f00 fs/bcachefs/btree_iter.c:2297 bch2_btree_iter_peek_upto_type fs/bcachefs/btree_iter.h:685 [inline] bch2_copygc_get_buckets fs/bcachefs/movinggc.c:164 [inline] bch2_copygc+0x8e2/0x4650 fs/bcachefs/movinggc.c:215 bch2_copygc_thread+0x737/0xc20 fs/bcachefs/movinggc.c:375 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244