INFO: task syz.4.40:6264 blocked for more than 143 seconds. Not tainted 6.12.0-syzkaller-11677-g2ba9f676d0a2 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.40 state:D stack:27360 pid:6264 tgid:6229 ppid:5833 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:5369 [inline] __schedule+0x17fb/0x4be0 kernel/sched/core.c:6756 __schedule_loop kernel/sched/core.c:6833 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6848 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6905 __mutex_lock_common kernel/locking/mutex.c:665 [inline] __mutex_lock+0x7e7/0xee0 kernel/locking/mutex.c:735 fdget_pos+0x254/0x320 fs/file.c:1191 class_fd_pos_constructor include/linux/file.h:85 [inline] ksys_lseek fs/read_write.c:389 [inline] __do_sys_lseek fs/read_write.c:405 [inline] __se_sys_lseek fs/read_write.c:403 [inline] __x64_sys_lseek+0x7a/0x1e0 fs/read_write.c:403 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: 0033:0x7f670ab80849 RSP: 002b:00007f670ba1e058 EFLAGS: 00000246 ORIG_RAX: 0000000000000008 RAX: ffffffffffffffda RBX: 00007f670ad46080 RCX: 00007f670ab80849 RDX: 0000000000000004 RSI: 0000000000000000 RDI: 0000000000000006 RBP: 00007f670abf3986 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000001 R14: 00007f670ad46080 R15: 00007ffd14276d18 INFO: task syz.4.40:6265 blocked for more than 143 seconds. Not tainted 6.12.0-syzkaller-11677-g2ba9f676d0a2 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.40 state:D stack:21824 pid:6265 tgid:6229 ppid:5833 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:5369 [inline] __schedule+0x17fb/0x4be0 kernel/sched/core.c:6756 __schedule_loop kernel/sched/core.c:6833 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6848 io_schedule+0x8d/0x110 kernel/sched/core.c:7681 folio_wait_bit_common+0x882/0x12b0 mm/filemap.c:1308 folio_wait_writeback+0xe7/0x1e0 mm/page-writeback.c:3194 truncate_inode_partial_folio+0xb1/0x640 mm/truncate.c:192 truncate_inode_pages_range+0x60a/0xfc0 mm/truncate.c:338 truncate_inode_pages mm/truncate.c:407 [inline] truncate_pagecache mm/truncate.c:715 [inline] truncate_setsize+0xcf/0xf0 mm/truncate.c:740 bchfs_truncate+0x6f3/0xc90 fs/bcachefs/fs-io.c:441 notify_change+0xbca/0xe90 fs/attr.c:552 do_truncate+0x220/0x310 fs/open.c:65 handle_truncate fs/namei.c:3449 [inline] do_open fs/namei.c:3832 [inline] path_openat+0x2e1e/0x3590 fs/namei.c:3987 do_filp_open+0x27f/0x4e0 fs/namei.c:4014 do_sys_openat2+0x13e/0x1d0 fs/open.c:1402 do_sys_open fs/open.c:1417 [inline] __do_sys_creat fs/open.c:1495 [inline] __se_sys_creat fs/open.c:1489 [inline] __x64_sys_creat+0x123/0x170 fs/open.c:1489 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: 0033:0x7f670ab80849 RSP: 002b:00007f670b9fd058 EFLAGS: 00000246 ORIG_RAX: 0000000000000055 RAX: ffffffffffffffda RBX: 00007f670ad46160 RCX: 00007f670ab80849 RDX: 0000000000000000 RSI: 0000000000000125 RDI: 0000000020000000 RBP: 00007f670abf3986 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f670ad46160 R15: 00007ffd14276d18 Showing all locks held in the system: 3 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/0x1840 kernel/workqueue.c:3310 #1: ffffc90000107d00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline] #1: ffffc90000107d00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1840 kernel/workqueue.c:3310 #2: ffffffff8fccc248 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:276 5 locks held by kworker/u8:1/12: #0: ffff88801baeb148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline] #0: ffff88801baeb148 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1840 kernel/workqueue.c:3310 #1: ffffc90000117d00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline] #1: ffffc90000117d00 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1840 kernel/workqueue.c:3310 #2: ffffffff8fcbf710 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0x16a/0xcc0 net/core/net_namespace.c:586 #3: ffffffff8fccc248 (rtnl_mutex){+.+.}-{4:4}, at: default_device_exit_batch+0xe9/0xaa0 net/core/dev.c:12053 #4: ffffffff8e941b38 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:329 [inline] #4: ffffffff8e941b38 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x451/0x830 kernel/rcu/tree_exp.h:976 1 lock held by khungtaskd/30: #0: ffffffff8e93c5a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #0: ffffffff8e93c5a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff8e93c5a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6744 3 locks held by kworker/u8:4/63: #0: ffff8880b863e758 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:598 #1: ffff8880222ce418 (&p->pi_lock){-.-.}-{2:2}, at: process_one_work kernel/workqueue.c:3205 [inline] #1: ffff8880222ce418 (&p->pi_lock){-.-.}-{2:2}, at: process_scheduled_works+0x976/0x1840 kernel/workqueue.c:3310 #2: ffff8880b862a718 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x112/0x240 kernel/time/timer.c:1050 1 lock held by dhcpcd/5493: #0: ffffffff8fccc248 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:128 [inline] #0: ffffffff8fccc248 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x47e/0x1bd0 net/ipv4/devinet.c:987 2 locks held by getty/5581: #0: ffff888035c820a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90002fde2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x6a6/0x1e00 drivers/tty/n_tty.c:2211 2 locks held by syz.4.40/6230: #0: ffff88805f3b40f8 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x254/0x320 fs/file.c:1191 #1: ffff88802a2c0420 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2964 [inline] #1: ffff88802a2c0420 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x225/0xd30 fs/read_write.c:675 1 lock held by syz.4.40/6264: #0: ffff88805f3b40f8 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x254/0x320 fs/file.c:1191 2 locks held by syz.4.40/6265: #0: ffff88802a2c0420 (sb_writers#17){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:515 #1: ffff88804faa9f48 (&sb->s_type->i_mutex_key#27){++++}-{4:4}, at: inode_lock include/linux/fs.h:818 [inline] #1: ffff88804faa9f48 (&sb->s_type->i_mutex_key#27){++++}-{4:4}, at: do_truncate+0x20c/0x310 fs/open.c:63 4 locks held by bch-reclaim/loo/6242: #0: ffff8880517cb0a8 (&j->reclaim_lock){+.+.}-{4:4}, at: bch2_journal_reclaim_thread+0x167/0x560 fs/bcachefs/journal_reclaim.c:739 #1: ffff888051784398 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:158 [inline] #1: ffff888051784398 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:249 [inline] #1: ffff888051784398 (&c->btree_trans_barrier){.+.+}-{0:0}, at: __bch2_trans_get+0x7e1/0xd30 fs/bcachefs/btree_iter.c:3228 #2: ffff888051784740 (&wb->flushing.lock){+.+.}-{4:4}, at: btree_write_buffer_flush_seq+0x1b19/0x1cc0 fs/bcachefs/btree_write_buffer.c:516 #3: ffff8880517a66d0 (&c->gc_lock){++++}-{4:4}, at: bch2_btree_update_start+0x682/0x14e0 fs/bcachefs/btree_update_interior.c:1197 4 locks held by syz-executor/6738: 1 lock held by syz-executor/6881: #0: ffffffff8e941b38 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:329 [inline] #0: ffffffff8e941b38 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x451/0x830 kernel/rcu/tree_exp.h:976 2 locks held by syz.9.343/9447: #0: ffff88802a2c00e0 (&type->s_umount_key#83){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88802a2c00e0 (&type->s_umount_key#83){++++}-{4:4}, at: super_lock+0x27c/0x400 fs/super.c:120 #1: ffff88802a2c0948 (&s->s_sync_lock){+.+.}-{4:4}, at: wait_sb_inodes fs/fs-writeback.c:2641 [inline] #1: ffff88802a2c0948 (&s->s_sync_lock){+.+.}-{4:4}, at: sync_inodes_sb+0x32e/0xb50 fs/fs-writeback.c:2824 1 lock held by syz-executor/9556: #0: ffffffff8fccc248 (rtnl_mutex){+.+.}-{4:4}, at: __tun_chr_ioctl+0x48c/0x2400 drivers/net/tun.c:3121 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.12.0-syzkaller-11677-g2ba9f676d0a2 #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:234 [inline] watchdog+0xff6/0x1040 kernel/hung_task.c:397 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: 63 Comm: kworker/u8:4 Not tainted 6.12.0-syzkaller-11677-g2ba9f676d0a2 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Workqueue: writeback wb_workfn (flush-8:0) RIP: 0010:__lock_acquire+0x6e/0x2100 kernel/locking/lockdep.c:5089 Code: c0 0f 85 f8 16 00 00 45 31 f6 83 3d 0b 82 ab 0e 00 0f 84 c8 13 00 00 89 54 24 60 89 5c 24 38 4c 89 f8 48 c1 e8 03 80 3c 30 00 <74> 12 4c 89 ff e8 e8 7b 8c 00 48 be 00 00 00 00 00 fc ff df 49 8b RSP: 0018:ffffc9000215f2f0 EFLAGS: 00000046 RAX: 1ffffffff34848be RBX: 0000000000000002 RCX: 0000000000000002 RDX: 0000000000000000 RSI: dffffc0000000000 RDI: ffffffff9a4245f0 RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000001 R10: dffffc0000000000 R11: fffffbfff2038e17 R12: ffff88801cb98000 R13: 0000000000000000 R14: 0000000000000000 R15: ffffffff9a4245f0 FS: 0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000555571a655c8 CR3: 000000000e738000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 seqcount_lockdep_reader_access include/linux/seqlock.h:72 [inline] fprop_fraction_percpu+0x19a/0x440 lib/flex_proportions.c:155 __wb_calc_thresh+0x173/0x520 mm/page-writeback.c:929 wb_bg_dirty_limits mm/page-writeback.c:2177 [inline] domain_over_bg_thresh mm/page-writeback.c:2191 [inline] wb_over_bg_thresh+0x28d/0x600 mm/page-writeback.c:2212 wb_check_background_flush fs/fs-writeback.c:2218 [inline] wb_do_writeback fs/fs-writeback.c:2316 [inline] wb_workfn+0xbcb/0x1080 fs/fs-writeback.c:2343 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310 worker_thread+0x870/0xd30 kernel/workqueue.c:3391 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