syzbot


INFO: task hung in path_mount (4)

Status: auto-obsoleted due to no activity on 2025/10/19 07:23
Subsystems: bcachefs
[Documentation on labels]
First crash: 409d, last: 102d
Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in path_mount (2) jfs 1 C error done 8 676d 804d 25/29 fixed on 2024/01/30 23:26
upstream INFO: task hung in path_mount fs arm 1 2 931d 1022d 0/29 auto-obsoleted due to no activity on 2023/07/13 21:53
upstream INFO: task hung in path_mount (3) jfs 1 1 607d 607d 0/29 auto-obsoleted due to no activity on 2024/06/01 10:11

Sample crash report:
INFO: task syz.9.327:9237 blocked for more than 143 seconds.
      Not tainted 6.16.0-rc7-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.9.327       state:D stack:21288 pid:9237  tgid:9225  ppid:7007   task_flags:0x400140 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5397 [inline]
 __schedule+0x16aa/0x4c90 kernel/sched/core.c:6786
 __schedule_loop kernel/sched/core.c:6864 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6879
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6936
 rwsem_down_write_slowpath+0xbec/0x1030 kernel/locking/rwsem.c:1176
 __down_write_common kernel/locking/rwsem.c:1304 [inline]
 __down_write kernel/locking/rwsem.c:1313 [inline]
 down_write+0x1ab/0x1f0 kernel/locking/rwsem.c:1578
 do_remount fs/namespace.c:3383 [inline]
 path_mount+0xcd2/0xfe0 fs/namespace.c:4218
 do_mount fs/namespace.c:4239 [inline]
 __do_sys_mount fs/namespace.c:4450 [inline]
 __se_sys_mount+0x317/0x410 fs/namespace.c:4427
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fba9378e9a9
RSP: 002b:00007fba94689038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fba939b6080 RCX: 00007fba9378e9a9
RDX: 0000000000000000 RSI: 00002000000001c0 RDI: 0000000000000000
RBP: 00007fba93810d69 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000010f482a R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fba939b6080 R15: 00007ffdbd983978
 </TASK>

Showing all locks held in the system:
3 locks held by kworker/u8:0/12:
 #0: ffff88801a489148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
 #0: ffff88801a489148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321
 #1: ffffc90000117bc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #1: ffffc90000117bc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321
 #2: ffffffff8f509e88 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:303
1 lock held by khungtaskd/31:
 #0: ffffffff8e13f0e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8e13f0e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8e13f0e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6770
3 locks held by kworker/u8:5/1014:
 #0: ffff88814c642948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
 #0: ffff88814c642948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321
 #1: ffffc90003a5fbc0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #1: ffffc90003a5fbc0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321
 #2: ffffffff8f509e88 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
 #2: ffffffff8f509e88 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x112/0x14b0 net/ipv6/addrconf.c:4193
6 locks held by kworker/u8:6/3458:
 #0: ffff88801b2fb948 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
 #0: ffff88801b2fb948 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321
 #1: ffffc9000c07fbc0 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #1: ffffc9000c07fbc0 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321
 #2: ffffffff8f4fd290 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf7/0x800 net/core/net_namespace.c:662
 #3: ffff888030da80e8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:884 [inline]
 #3: ffff888030da80e8 (&dev->mutex){....}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:108 [inline]
 #3: ffff888030da80e8 (&dev->mutex){....}-{4:4}, at: devlink_pernet_pre_exit+0x10a/0x3d0 net/devlink/core.c:506
 #4: ffff88802a264250 (&devlink->lock_key#23){+.+.}-{4:4}, at: devl_lock net/devlink/core.c:276 [inline]
 #4: ffff88802a264250 (&devlink->lock_key#23){+.+.}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:109 [inline]
 #4: ffff88802a264250 (&devlink->lock_key#23){+.+.}-{4:4}, at: devlink_pernet_pre_exit+0x11c/0x3d0 net/devlink/core.c:506
 #5: ffffffff8f509e88 (rtnl_mutex){+.+.}-{4:4}, at: nsim_destroy+0xdb/0x670 drivers/net/netdevsim/netdev.c:1064
2 locks held by dhcpcd/5500:
 #0: ffffffff8f570170 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
 #1: ffffffff8f56ff88 (genl_mutex){+.+.}-{4:4}, at: genl_lock net/netlink/genetlink.c:35 [inline]
 #1: ffffffff8f56ff88 (genl_mutex){+.+.}-{4:4}, at: genl_op_lock net/netlink/genetlink.c:60 [inline]
 #1: ffffffff8f56ff88 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10d/0x790 net/netlink/genetlink.c:1209
2 locks held by getty/5597:
 #0: ffff88814c7830a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000333b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
3 locks held by syz.9.327/9226:
 #0: ffff88807e8820e0 (&type->s_umount_key#80){++++}-{4:4}, at: __super_lock fs/super.c:59 [inline]
 #0: ffff88807e8820e0 (&type->s_umount_key#80){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:121
 #1: ffff888046a04398 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:161 [inline]
 #1: ffff888046a04398 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:253 [inline]
 #1: ffff888046a04398 (&c->btree_trans_barrier){.+.+}-{0:0}, at: bch2_trans_srcu_lock+0xaf/0x220 fs/bcachefs/btree_iter.c:3299
 #2: ffff888046a26710 (&c->gc_lock){.+.+}-{4:4}, at: bch2_btree_update_start+0x542/0x1de0 fs/bcachefs/btree_update_interior.c:1211
1 lock held by syz.9.327/9237:
 #0: ffff88807e8820e0 (&type->s_umount_key#80){++++}-{4:4}, at: do_remount fs/namespace.c:3383 [inline]
 #0: ffff88807e8820e0 (&type->s_umount_key#80){++++}-{4:4}, at: path_mount+0xcd2/0xfe0 fs/namespace.c:4218
3 locks held by syz-executor/10608:
 #0: ffffffff8f570170 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
 #1: ffffffff8f56ff88 (genl_mutex){+.+.}-{4:4}, at: genl_lock net/netlink/genetlink.c:35 [inline]
 #1: ffffffff8f56ff88 (genl_mutex){+.+.}-{4:4}, at: genl_op_lock net/netlink/genetlink.c:60 [inline]
 #1: ffffffff8f56ff88 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10d/0x790 net/netlink/genetlink.c:1209
 #2: ffffffff8f509e88 (rtnl_mutex){+.+.}-{4:4}, at: ieee80211_register_hw+0x3416/0x4120 net/mac80211/main.c:1598
1 lock held by syz-executor/10707:
 #0: ffffffff8f509e88 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
 #0: ffffffff8f509e88 (rtnl_mutex){+.+.}-{4:4}, at: inet6_rtm_newaddr+0x5b7/0xd20 net/ipv6/addrconf.c:5026
2 locks held by syz-executor/11332:
 #0: ffffffff8f4fd290 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x304/0x4d0 net/core/net_namespace.c:570
 #1: ffffffff8f509e88 (rtnl_mutex){+.+.}-{4:4}, at: register_nexthop_notifier+0x80/0x210 net/ipv4/nexthop.c:3929
2 locks held by syz-executor/11343:

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.16.0-rc7-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 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:307 [inline]
 watchdog+0xfee/0x1030 kernel/hung_task.c:470
 kthread+0x711/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 5845 Comm: kworker/u9:4 Not tainted 6.16.0-rc7-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: hci3 hci_rx_work
RIP: 0010:arch_static_branch arch/x86/include/asm/jump_label.h:36 [inline]
RIP: 0010:native_write_msr arch/x86/include/asm/msr.h:139 [inline]
RIP: 0010:wrmsrq arch/x86/include/asm/msr.h:199 [inline]
RIP: 0010:native_apic_msr_write+0x39/0x50 arch/x86/include/asm/apic.h:212
Code: 74 2a 83 ff 30 74 25 eb 10 81 ff d0 00 00 00 74 1b 81 ff e0 00 00 00 74 13 c1 ef 04 81 c7 00 08 00 00 89 f9 89 f0 31 d2 0f 30 <66> 90 c3 cc cc cc cc cc f3 0f 1e fa 89 f6 31 d2 e9 e2 c9 7e 03 66
RSP: 0018:ffffc90000007e50 EFLAGS: 00000046
RAX: 0000000000096bc3 RBX: ffff8880b8623900 RCX: 0000000000000838
RDX: 0000000000000000 RSI: 0000000000096bc3 RDI: 0000000000000838
RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff81aec6de
R10: 0000000000000003 R11: ffffffff81702490 R12: 00000000100053e2
R13: dffffc0000000000 R14: 0000000000096bc3 R15: 0000000000000020
FS:  0000000000000000(0000) GS:ffff888125c57000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000556200da8000 CR3: 000000007616a000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 apic_write arch/x86/include/asm/apic.h:405 [inline]
 lapic_next_event+0x11/0x20 arch/x86/kernel/apic/apic.c:416
 clockevents_program_event+0x1cc/0x360 kernel/time/clockevents.c:334
 hrtimer_interrupt+0x620/0xaa0 kernel/time/hrtimer.c:1900
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline]
 __sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1056
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1050
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:console_trylock_spinning kernel/printk/printk.c:2061 [inline]
RIP: 0010:vprintk_emit+0x58f/0x7a0 kernel/printk/printk.c:2449
Code: 85 32 01 00 00 e8 d1 23 1f 00 41 89 df 4d 85 f6 48 8b 1c 24 75 07 e8 c0 23 1f 00 eb 06 e8 b9 23 1f 00 fb 48 c7 c7 60 33 13 8e <31> f6 ba 01 00 00 00 31 c9 41 b8 01 00 00 00 45 31 c9 53 e8 19 37
RSP: 0018:ffffc900041cf4c0 EFLAGS: 00000287
RAX: ffffffff81a101f7 RBX: ffffffff81a100b4 RCX: 0000000000100000
RDX: ffffc9001a72e000 RSI: 000000000000ba04 RDI: ffffffff8e133360
RBP: ffffc900041cf5d0 R08: ffffffff8fa0b2f7 R09: 1ffffffff1f4165e
R10: dffffc0000000000 R11: fffffbfff1f4165f R12: dffffc0000000000
R13: 1ffff92000839e9c R14: 0000000000000200 R15: 0000000000000035
 _printk+0xcf/0x120 kernel/printk/printk.c:2475
 bt_warn+0x10b/0x160 net/bluetooth/lib.c:276
 hci_cc_func net/bluetooth/hci_event.c:4168 [inline]
 hci_cmd_complete_evt+0x478/0x960 net/bluetooth/hci_event.c:4192
 hci_event_func net/bluetooth/hci_event.c:7474 [inline]
 hci_event_packet+0x78f/0x1200 net/bluetooth/hci_event.c:7531
 hci_rx_work+0x46a/0xe80 net/bluetooth/hci_core.c:4070
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x711/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Crashes (16):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/07/21 07:13 upstream 89be9a83ccf1 7117feec .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in path_mount
2025/07/21 03:45 upstream 89be9a83ccf1 7117feec .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in path_mount
2025/05/04 05:56 upstream 2a239ffbebb5 b0714e37 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in path_mount
2025/04/27 11:02 upstream 5bc1018675ec c6b4fb39 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in path_mount
2025/03/13 16:01 upstream b7f94fcf5546 44be8b44 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in path_mount
2025/02/13 13:57 upstream 4dc1d1bec898 a98a8417 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in path_mount
2025/02/08 16:47 upstream 8f6629c004b1 ef44b750 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: task hung in path_mount
2025/02/08 02:01 upstream 7ee983c850b4 ef44b750 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in path_mount
2025/01/11 09:48 upstream 77a903cd8e5a 6dbc6a9b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in path_mount
2025/01/08 15:00 upstream 09a0fa92e5b4 f3558dbf .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in path_mount
2024/12/23 22:43 upstream f07044dd0df0 444551c4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in path_mount
2024/12/17 12:42 upstream f44d154d6e3d f93b2b55 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in path_mount
2024/12/09 21:20 upstream fac04efc5c79 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in path_mount
2024/09/17 23:12 upstream fc1dc0d50780 c673ca06 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: task hung in path_mount
2025/02/10 07:02 linux-next df5d6180169a ef44b750 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task hung in path_mount
2025/02/08 15:26 linux-next ed58d103e6da ef44b750 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task hung in path_mount
* Struck through repros no longer work on HEAD.