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INFO: rcu detected stall in sys_flock (2)

Status: auto-obsoleted due to no activity on 2025/03/20 01:25
Subsystems: fs
[Documentation on labels]
First crash: 495d, last: 495d
▶ ▼ Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in sys_flock (3) mm 1 1 269d 269d 0/29 auto-obsoleted due to no activity on 2025/11/01 23:21
linux-5.15 INFO: rcu detected stall in flock 1 1 207d 207d 0/3 auto-obsoleted due to no activity on 2026/01/12 22:11
linux-6.1 INFO: rcu detected stall in flock 1 1 32d 32d 0/3 upstream: reported on 2026/03/28 08:14
upstream INFO: rcu detected stall in sys_flock fs 1 1 643d 643d 0/29 auto-obsoleted due to no activity on 2024/10/23 09:08
linux-5.15 INFO: rcu detected stall in flock (2) 1 1 74d 74d 0/3 upstream: reported on 2026/02/14 22:22

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (0 ticks this GP) idle=067c/1/0x4000000000000000 softirq=65055/65055 fqs=0
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P11717/1:b..l
rcu: 	(detected by 0, t=10506 jiffies, g=51485, q=973 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 14853 Comm: udevd Not tainted 6.13.0-rc3-syzkaller-00073-geabcdba3ad40 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/25/2024
RIP: 0010:__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:108 [inline]
RIP: 0010:_raw_spin_lock_irqsave+0xa2/0x120 kernel/locking/spinlock.c:162
Code: 89 e7 e8 91 9c 3a f6 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 42 80 3c 3b 00 74 08 4c 89 e7 e8 84 9b 3a f6 4c 8b 64 24 20 fa <41> f7 c4 00 02 00 00 74 05 e8 60 f6 db f5 bf 01 00 00 00 e8 76 48
RSP: 0018:ffffc90000a18b40 EFLAGS: 00000046
RAX: f3f3f300f1f1f1f1 RBX: 1ffff9200014316c RCX: 0000000000003f08
RDX: 0000000000000010 RSI: 0000000000000000 RDI: ffffffff9a597210
RBP: ffffc90000a18bd0 R08: ffffc90000a18c4f R09: ffffc90000a18c40
R10: dffffc0000000000 R11: fffff5200014318a R12: 0000000000000046
R13: 1ffff92000143168 R14: ffffffff9a597210 R15: dffffc0000000000
FS:  00007fbccf08fc80(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f02fa16b500 CR3: 000000005d146000 CR4: 0000000000350ef0
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 debug_object_activate+0x17f/0x580 lib/debugobjects.c:818
 debug_hrtimer_activate kernel/time/hrtimer.c:428 [inline]
 debug_activate kernel/time/hrtimer.c:469 [inline]
 enqueue_hrtimer+0x30/0x3c0 kernel/time/hrtimer.c:1076
 __run_hrtimer kernel/time/hrtimer.c:1756 [inline]
 __hrtimer_run_queues+0x6cb/0xd30 kernel/time/hrtimer.c:1803
 hrtimer_interrupt+0x403/0xa40 kernel/time/hrtimer.c:1865
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline]
 __sysvec_apic_timer_interrupt+0x112/0x420 arch/x86/kernel/apic/apic.c:1055
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
 sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1049
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xd8/0x140 kernel/locking/spinlock.c:194
Code: 9c 8f 44 24 20 42 80 3c 23 00 74 08 4c 89 f7 e8 3e 98 3a f6 f6 44 24 21 02 75 52 41 f7 c7 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> d3 46 a2 f5 65 8b 05 74 9a 38 74 85 c0 74 43 48 c7 04 24 0e 36
RSP: 0018:ffffc9000c2676a0 EFLAGS: 00000206
RAX: 54e839fff7e0ad00 RBX: 1ffff9200184ced8 RCX: ffffffff817b275a
RDX: dffffc0000000000 RSI: ffffffff8c0a9760 RDI: 0000000000000001
RBP: ffffc9000c267730 R08: ffffffff942a38b7 R09: 1ffffffff2854716
R10: dffffc0000000000 R11: fffffbfff2854717 R12: dffffc0000000000
R13: 1ffff9200184ced4 R14: ffffc9000c2676c0 R15: 0000000000000246
 __debug_check_no_obj_freed lib/debugobjects.c:1108 [inline]
 debug_check_no_obj_freed+0x561/0x580 lib/debugobjects.c:1129
 free_pages_prepare mm/page_alloc.c:1134 [inline]
 free_unref_page+0x4cb/0x1010 mm/page_alloc.c:2657
 __slab_free+0x2c2/0x380 mm/slub.c:4524
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4119 [inline]
 slab_alloc_node mm/slub.c:4168 [inline]
 kmem_cache_alloc_noprof+0x1d9/0x380 mm/slub.c:4175
 locks_alloc_lock fs/locks.c:275 [inline]
 flock_lock_inode+0x2ee/0x1450 fs/locks.c:1091
 flock_lock_inode_wait fs/locks.c:2084 [inline]
 locks_lock_inode_wait+0x108/0x460 fs/locks.c:2111
 locks_lock_file_wait include/linux/filelock.h:422 [inline]
 __do_sys_flock fs/locks.c:2179 [inline]
 __se_sys_flock+0x526/0x6e0 fs/locks.c:2135
 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: 0033:0x7fbccf15afc7
Code: ae 30 fa ff 48 8b 04 24 eb 05 e8 ec 33 00 00 48 83 c4 68 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 49 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 31 9e 0d 00 f7 d8 64 89 01 48
RSP: 002b:00007fffdeb5e4e8 EFLAGS: 00000202 ORIG_RAX: 0000000000000049
RAX: ffffffffffffffda RBX: 000056295822dec0 RCX: 00007fbccf15afc7
RDX: 00000000000a0800 RSI: 0000000000000005 RDI: 0000000000000008
RBP: 000056295822dec0 R08: 00000000ffffffff R09: 7fffffffffffffff
R10: 0000000000000000 R11: 0000000000000202 R12: 000056295823f940
R13: 0000562958224ce0 R14: 0000000000000008 R15: 0000562958219910
 </TASK>
task:syz-executor    state:R  running task     stack:20304 pid:11717 tgid:11717 ppid:11701  flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5369 [inline]
 __schedule+0x1850/0x4c30 kernel/sched/core.c:6756
 preempt_schedule_common+0x84/0xd0 kernel/sched/core.c:6935
 preempt_schedule+0xe1/0xf0 kernel/sched/core.c:6959
 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk.S:12
 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
 _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:391 [inline]
 copy_pte_range mm/memory.c:1200 [inline]
 copy_pmd_range+0x6dc8/0x77a0 mm/memory.c:1261
 copy_pud_range mm/memory.c:1298 [inline]
 copy_p4d_range mm/memory.c:1322 [inline]
 copy_page_range+0x99f/0xe90 mm/memory.c:1420
 dup_mmap kernel/fork.c:751 [inline]
 dup_mm kernel/fork.c:1695 [inline]
 copy_mm+0x11c7/0x1f90 kernel/fork.c:1744
 copy_process+0x1845/0x3d50 kernel/fork.c:2395
 kernel_clone+0x226/0x8e0 kernel/fork.c:2807
 __do_sys_clone kernel/fork.c:2950 [inline]
 __se_sys_clone kernel/fork.c:2934 [inline]
 __x64_sys_clone+0x258/0x2a0 kernel/fork.c:2934
 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: 0033:0x7fdb3617c593
RSP: 002b:00007ffce90eb818 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fdb3617c593
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001
R10: 0000555581ff37d0 R11: 0000000000000246 R12: 0000000000000000
R13: 00000000000af604 R14: 00007ffce90eb9a0 R15: 0000000000000078
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10505 jiffies! g51485 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=51487
rcu: rcu_preempt kthread starved for 10506 jiffies! g51485 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=1
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt     state:I stack:23480 pid:17    tgid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5369 [inline]
 __schedule+0x1850/0x4c30 kernel/sched/core.c:6756
 __schedule_loop kernel/sched/core.c:6833 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6848
 schedule_timeout+0x15a/0x290 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2045
 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2247
 kthread+0x2f2/0x390 kernel/kthread.c:389
 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/12/20 01:24 upstream eabcdba3ad40 1d58202c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in sys_flock
* Struck through repros no longer work on HEAD.