syzbot


INFO: task hung in bchfs_fpunch

Status: auto-obsoleted due to no activity on 2025/03/30 07:10
Subsystems: fs mm
[Documentation on labels]
First crash: 372d, last: 277d
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in bchfs_fpunch (2) bcachefs 1 C done 2 57d 101d 2/29 upstream: reported C repro on 2025/06/24 19:01

Sample crash report:
INFO: task syz.0.44:6183 blocked for more than 143 seconds.
      Not tainted 6.13.0-rc4-syzkaller-00110-g4099a71718b0 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.44        state:D stack:24032 pid:6183  tgid:6162  ppid:5814   flags:0x00000006
Call Trace:
 <TASK>
 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+0x839/0xee0 mm/filemap.c:1308
 folio_wait_writeback+0xb0/0x100 mm/page-writeback.c:3194
 truncate_inode_pages_range+0xc90/0x10e0 mm/truncate.c:382
 bchfs_fpunch+0x1c1/0x780 fs/bcachefs/fs-io.c:514
 bch2_fallocate_dispatch+0x3e4/0x540 fs/bcachefs/fs-io.c:782
 vfs_fallocate+0x569/0x6e0 fs/open.c:327
 do_vfs_ioctl+0x258c/0x2e40 fs/ioctl.c:885
 __do_sys_ioctl fs/ioctl.c:904 [inline]
 __se_sys_ioctl+0x80/0x170 fs/ioctl.c:892
 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: 0033:0x7fab59785d29
RSP: 002b:00007fab5a5e5038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fab59976080 RCX: 00007fab59785d29
RDX: 0000000020000b40 RSI: 0000000040305829 RDI: 0000000000000004
RBP: 00007fab59801b08 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007fab59976080 R15: 00007ffed4dc7db8
 </TASK>

Showing all locks held in the system:
3 locks held by kworker/u8:1/12:
 #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: ffffc90000117d00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
 #1: ffffc90000117d00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1840 kernel/workqueue.c:3310
 #2: ffffffff8fca0808 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:281
1 lock held by khungtaskd/30:
 #0: ffffffff8e937ae0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 #0: ffffffff8e937ae0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8e937ae0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6744
5 locks held by kworker/u8:4/66:
 #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: ffffc9000217fd00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
 #1: ffffc9000217fd00 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1840 kernel/workqueue.c:3310
 #2: ffffffff8fc94350 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0x16a/0xd50 net/core/net_namespace.c:602
 #3: ffffffff8fca0808 (rtnl_mutex){+.+.}-{4:4}, at: default_device_exit_batch+0xe9/0xaa0 net/core/dev.c:12059
 #4: ffffffff8e93cff8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:297 [inline]
 #4: ffffffff8e93cff8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x381/0x830 kernel/rcu/tree_exp.h:976
3 locks held by kworker/u8:5/1034:
 #0: ffff88814dc7b148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
 #0: ffff88814dc7b148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1840 kernel/workqueue.c:3310
 #1: ffffc90003cefd00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
 #1: ffffc90003cefd00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1840 kernel/workqueue.c:3310
 #2: ffffffff8fca0808 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0xd0/0x16f0 net/ipv6/addrconf.c:4215
3 locks held by kworker/u8:6/2909:
 #0: ffff8881412d4148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
 #0: ffff8881412d4148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1840 kernel/workqueue.c:3310
 #1: ffffc9000c1e7d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
 #1: ffffc9000c1e7d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1840 kernel/workqueue.c:3310
 #2: ffff88802907c0e0 (&type->s_umount_key#63){++++}-{4:4}, at: super_trylock_shared+0x22/0xf0 fs/super.c:562
1 lock held by dhcpcd/5486:
 #0: ffffffff8fca0808 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:128 [inline]
 #0: ffffffff8fca0808 (rtnl_mutex){+.+.}-{4:4}, at: devinet_ioctl+0x31a/0x1ac0 net/ipv4/devinet.c:1129
2 locks held by getty/5569:
 #0: ffff88814dede0a0 (&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
1 lock held by syz.0.44/6163:
 #0: ffff88802907c420 (sb_writers#15){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2964 [inline]
 #0: ffff88802907c420 (sb_writers#15){.+.+}-{0:0}, at: vfs_write+0x225/0xd30 fs/read_write.c:675
2 locks held by syz.0.44/6183:
 #0: ffff88802907c420 (sb_writers#15){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2964 [inline]
 #0: ffff88802907c420 (sb_writers#15){.+.+}-{0:0}, at: vfs_fallocate+0x4fe/0x6e0 fs/open.c:326
 #1: ffff88805d1d1048 (&sb->s_type->i_mutex_key#23){++++}-{4:4}, at: inode_lock include/linux/fs.h:818 [inline]
 #1: ffff88805d1d1048 (&sb->s_type->i_mutex_key#23){++++}-{4:4}, at: bch2_fallocate_dispatch+0x1e2/0x540 fs/bcachefs/fs-io.c:771
4 locks held by bch-reclaim/loo/6176:
 #0: ffff8880510cb0a8 (&j->reclaim_lock){+.+.}-{4:4}, at: bch2_journal_reclaim_thread+0x167/0x560 fs/bcachefs/journal_reclaim.c:739
 #1: ffff888051084398 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:158 [inline]
 #1: ffff888051084398 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:249 [inline]
 #1: ffff888051084398 (&c->btree_trans_barrier){.+.+}-{0:0}, at: __bch2_trans_get+0x7e1/0xd30 fs/bcachefs/btree_iter.c:3228
 #2: ffff888051084740 (&wb->flushing.lock){+.+.}-{4:4}, at: btree_write_buffer_flush_seq+0x1b19/0x1cc0 fs/bcachefs/btree_write_buffer.c:516
 #3: ffff8880510a66d0 (&c->gc_lock){++++}-{4:4}, at: bch2_btree_update_start+0x682/0x14e0 fs/bcachefs/btree_update_interior.c:1197
1 lock held by syz-executor/8320:
 #0: ffffffff8fca0808 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:128 [inline]
 #0: ffffffff8fca0808 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x47e/0x1bd0 net/ipv4/devinet.c:987
1 lock held by syz-executor/8523:
 #0: ffffffff8fca0808 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
 #0: ffffffff8fca0808 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:326 [inline]
 #0: ffffffff8fca0808 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0xce2/0x2210 net/core/rtnetlink.c:4011

=============================================

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.13.0-rc4-syzkaller-00110-g4099a71718b0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <TASK>
 __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
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 5878 Comm: kworker/u8:7 Not tainted 6.13.0-rc4-syzkaller-00110-g4099a71718b0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet
RIP: 0010:batadv_iv_ogm_schedule_buff net/batman-adv/bat_iv_ogm.c:843 [inline]
RIP: 0010:batadv_iv_ogm_schedule+0xa0d/0x10a0 net/batman-adv/bat_iv_ogm.c:868
Code: 30 48 c1 e8 03 48 89 44 24 60 49 c7 c7 40 c3 79 9a 49 8d 5e 78 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 <74> 08 48 89 df e8 79 5e 7c f6 48 8b 1b 48 b8 00 00 00 00 00 fc ff
RSP: 0018:ffffc900044cf9c0 EFLAGS: 00000246
RAX: 1ffff1100538530f RBX: ffff888029c29878 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000007 RDI: 0000000000000001
RBP: ffffc900044cfaf8 R08: ffffffff8b86f47c R09: 1ffff1100f91e204
R10: dffffc0000000000 R11: ffffed100f91e205 R12: ffff88807c8f2078
R13: ffff88807c8f2000 R14: ffff888029c29800 R15: ffffffff9a79c340
FS:  0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6a99d48178 CR3: 000000000e736000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 batadv_iv_send_outstanding_bat_ogm_packet+0x6fe/0x810 net/batman-adv/bat_iv_ogm.c:1712
 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
 </TASK>

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/12/30 07:07 upstream 4099a71718b0 d3ccff63 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bchfs_fpunch
2024/11/26 04:31 upstream 9f16d5e6f220 11dbc254 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bchfs_fpunch
2024/09/29 12:52 upstream 3efc57369a0c ba29ff75 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bchfs_fpunch
2024/09/29 12:50 upstream 3efc57369a0c ba29ff75 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bchfs_fpunch
2024/09/26 14:40 upstream 11a299a7933e 0d19f247 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bchfs_fpunch
* Struck through repros no longer work on HEAD.