syzbot


INFO: task hung in bch2_btree_update_start

Status: auto-obsoleted due to no activity on 2025/08/14 02:10
Subsystems: bcachefs
[Documentation on labels]
First crash: 284d, last: 147d

Sample crash report:
INFO: task syz.7.374:12052 blocked for more than 143 seconds.
      Not tainted 6.15.0-rc6-syzkaller-00105-g088d13246a46 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.7.374       state:D stack:14280 pid:12052 tgid:12051 ppid:8721   task_flags:0x400140 flags:0x00004006
Call Trace:
 <TASK>
 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
 bch2_btree_update_start+0x5c4/0x14c0 fs/bcachefs/btree_update_interior.c:1147
 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_set_rebalance_needs_scan+0x99/0x3a0 fs/bcachefs/rebalance.c:262
 bch2_run_recovery_pass+0xdf/0x1d0 fs/bcachefs/recovery_passes.c:227
 bch2_run_recovery_passes+0x2a0/0xdb0 fs/bcachefs/recovery_passes.c:280
 bch2_fs_recovery+0x2399/0x37b0 fs/bcachefs/recovery.c:937
 bch2_fs_start+0x70b/0xae0 fs/bcachefs/super.c:1096
 bch2_fs_get_tree+0xad7/0x13b0 fs/bcachefs/fs.c:2505
 vfs_get_tree+0x92/0x2b0 fs/super.c:1759
 do_new_mount+0x24a/0xa40 fs/namespace.c:3881
 do_mount fs/namespace.c:4221 [inline]
 __do_sys_mount fs/namespace.c:4432 [inline]
 __se_sys_mount+0x317/0x410 fs/namespace.c:4409
 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: 0033:0x7ffaf539010a
RSP: 002b:00007ffaf622de68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffaf622def0 RCX: 00007ffaf539010a
RDX: 00002000000000c0 RSI: 0000200000000000 RDI: 00007ffaf622deb0
RBP: 00002000000000c0 R08: 00007ffaf622def0 R09: 0000000000800000
R10: 0000000000800000 R11: 0000000000000246 R12: 0000200000000000
R13: 00007ffaf622deb0 R14: 0000000000005953 R15: 0000200000000080
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffffffff8df3dce0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8df3dce0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8df3dce0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6764
2 locks held by kworker/u8:3/53:
 #0: ffff88801a089148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
 #0: ffff88801a089148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b1/0x17a0 kernel/workqueue.c:3319
 #1: ffffc90000be7c60 ((reaper_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #1: ffffc90000be7c60 ((reaper_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ec/0x17a0 kernel/workqueue.c:3319
2 locks held by kworker/u8:4/64:
 #0: ffff8880b89399d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:605
 #1: ffff8880b8923b08 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x39e/0x6d0 kernel/sched/psi.c:987
3 locks held by kworker/u8:5/84:
 #0: ffff8880b89399d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:605
 #1: ffff8880b8923b08 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x39e/0x6d0 kernel/sched/psi.c:987
 #2: ffff8880648e0768 (&rdev->wiphy.mtx){+.+.}-{4:4}, at: class_wiphy_constructor include/net/cfg80211.h:6092 [inline]
 #2: ffff8880648e0768 (&rdev->wiphy.mtx){+.+.}-{4:4}, at: cfg80211_wiphy_work+0xc4/0x460 net/wireless/core.c:421
2 locks held by getty/5578:
 #0: ffff8880305340a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc90002ffe2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
1 lock held by udevd/5818:
1 lock held by syz-executor/11417:
1 lock held by syz.7.374/12052:
 #0: ffff88804a984228 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:161 [inline]
 #0: ffff88804a984228 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:253 [inline]
 #0: ffff88804a984228 (&c->btree_trans_barrier){.+.+}-{0:0}, at: __bch2_trans_get+0x806/0xda0 fs/bcachefs/btree_iter.c:3385
1 lock held by syz-executor/16073:
 #0: ffffffff8df437b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:304 [inline]
 #0: ffffffff8df437b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f4/0x730 kernel/rcu/tree_exp.h:998
1 lock held by syz.1.609/18031:
1 lock held by syz.8.614/18048:
 #0: ffffffff8df437b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:336 [inline]
 #0: ffffffff8df437b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b7/0x730 kernel/rcu/tree_exp.h:998
1 lock held by udevadm/18081:
3 locks held by rm/18101:

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-rc6-syzkaller-00105-g088d13246a46 #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: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
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 18101 Comm: rm Not tainted 6.15.0-rc6-syzkaller-00105-g088d13246a46 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:26 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:109 [inline]
RIP: 0010:check_preemption_disabled+0x59/0x120 lib/smp_processor_id.c:19
Code: 8b 0d 2b fe 22 07 48 3b 4c 24 08 0f 85 cc 00 00 00 48 83 c4 10 5b 41 5e 41 5f 5d e9 51 b5 02 00 cc 48 c7 04 24 00 00 00 00 9c <8f> 04 24 f7 04 24 00 02 00 00 74 c8 65 4c 8b 3c 25 08 50 72 92 41
RSP: 0018:ffffc9000b67f558 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000080000000
RDX: 0000000000000000 RSI: ffffffff8d922b3d RDI: ffffffff8bc10660
RBP: 00000000ffffffff R08: ffff88802b481e00 R09: 0000000000000003
R10: 0000000000000003 R11: 0000000000000000 R12: 0000000000000246
R13: ffff88802b481e00 R14: ffff8880285f47e0 R15: 0000000000000000
FS:  00007febfdbd9c80(0000) GS:ffff8881260fb000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007febfdf41000 CR3: 000000005ea56000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 lockdep_recursion_finish kernel/locking/lockdep.c:472 [inline]
 lock_is_held_type+0xfe/0x190 kernel/locking/lockdep.c:5939
 lock_is_held include/linux/lockdep.h:249 [inline]
 mt_locked lib/maple_tree.c:-1 [inline]
 mt_slot lib/maple_tree.c:800 [inline]
 mas_slot lib/maple_tree.c:833 [inline]
 mt_validate_nulls lib/maple_tree.c:7512 [inline]
 mt_validate+0x3dfc/0x4380 lib/maple_tree.c:7567
 validate_mm+0xb6/0x4b0 mm/vma.c:595
 __split_vma+0x867/0x9b0 mm/vma.c:524
 split_vma mm/vma.c:553 [inline]
 vma_modify+0x327/0x460 mm/vma.c:1587
 vma_modify_flags+0x1e8/0x230 mm/vma.c:1605
 mprotect_fixup+0x400/0x9b0 mm/mprotect.c:658
 do_mprotect_pkey+0x8cd/0xce0 mm/mprotect.c:832
 __do_sys_mprotect mm/mprotect.c:853 [inline]
 __se_sys_mprotect mm/mprotect.c:850 [inline]
 __x64_sys_mprotect+0x80/0x90 mm/mprotect.c:850
 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: 0033:0x7febfdf702c7
Code: 89 3d fd 3f 01 00 eb 90 0f 1f 00 f7 d8 89 05 f0 3f 01 00 48 c7 c0 ff ff ff ff eb 91 0f 1f 80 00 00 00 00 b8 0a 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8d 0d c9 3f 01 00 f7 d8 89 01 48 83
RSP: 002b:00007ffc57795c78 EFLAGS: 00000206 ORIG_RAX: 000000000000000a
RAX: ffffffffffffffda RBX: 00007febfdf84310 RCX: 00007febfdf702c7
RDX: 0000000000000001 RSI: 0000000000001000 RDI: 000055b426768000
RBP: 00007ffc57795f40 R08: 0000000000000000 R09: 00007febfdef30a2
R10: 00007febfdf84310 R11: 0000000000000206 R12: 0000000000000000
R13: 000000eb1bd582c7 R14: 0000000000000000 R15: 00007febfdf84310
 </TASK>

Crashes (12):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/05/16 01:59 upstream 088d13246a46 cfde8269 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_btree_update_start
2025/04/22 07:24 upstream a33b5a08cbbd 2a20f901 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_btree_update_start
2025/03/22 14:00 upstream 88d324e69ea9 c6512ef7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_btree_update_start
2025/03/21 00:27 upstream 5fc319360819 62330552 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_btree_update_start
2025/03/20 11:13 upstream a7f2e10ecd8f 9209bc22 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_btree_update_start
2025/02/02 05:53 upstream 69e858e0b8b2 0dff8567 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: task hung in bch2_btree_update_start
2025/01/09 18:03 upstream eea6e4b4dfb8 9220929f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_btree_update_start
2025/01/06 12:30 upstream ab75170520d4 f3558dbf .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: task hung in bch2_btree_update_start
2025/01/02 05:36 upstream 56e6a3499e14 d3ccff63 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_btree_update_start
2024/12/30 14:54 upstream fc033cf25e61 d3ccff63 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in bch2_btree_update_start
2025/01/04 14:12 linux-next 8155b4ef3466 f3558dbf .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task hung in bch2_btree_update_start
2025/04/06 15:00 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci d6b13dbd03b7 1c65791e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 INFO: task hung in bch2_btree_update_start
* Struck through repros no longer work on HEAD.