syzbot


INFO: rcu detected stall in dput

Status: upstream: reported on 2025/06/17 20:59
Reported-by: syzbot+d1665e7f42dee637973f@syzkaller.appspotmail.com
First crash: 47d, last: 1d00h
Similar bugs (12)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 INFO: rcu detected stall in dput (2) 1 39 11d 432d 0/3 upstream: reported on 2024/05/28 13:43
upstream INFO: rcu detected stall in dput (4) kvm 1 C error error 2 1332d 1692d 0/29 closed as invalid on 2022/02/08 10:37
linux-5.15 INFO: rcu detected stall in dput (3) 1 14 14d 237d 0/3 upstream: reported on 2024/12/09 17:03
upstream INFO: rcu detected stall in dput (3) mm 1 1 2034d 2034d 0/29 closed as invalid on 2020/01/09 08:13
upstream INFO: rcu detected stall in dput (8) mm fs 1 C done 425 17h08m 581d 0/29 upstream: reported C repro on 2023/12/31 19:35
linux-5.15 INFO: rcu detected stall in dput 1 2 705d 745d 0/3 auto-obsoleted due to no activity on 2023/12/08 00:28
upstream INFO: rcu detected stall in dput (6) fs 1 2 1006d 1066d 0/29 auto-obsoleted due to no activity on 2023/01/16 04:13
linux-5.15 INFO: rcu detected stall in dput (2) 1 10 364d 506d 0/3 auto-obsoleted due to no activity on 2024/11/12 09:55
upstream INFO: rcu detected stall in dput (5) fs 1 1 1202d 1202d 0/29 auto-closed as invalid on 2022/07/18 12:41
linux-6.1 INFO: rcu detected stall in dput 1 1 753d 753d 0/3 auto-obsoleted due to no activity on 2023/10/20 22:44
upstream INFO: rcu detected stall in dput fs 1 1 2070d 2070d 0/29 closed as invalid on 2019/12/04 14:04
upstream INFO: rcu detected stall in dput (2) mm 1 2 2035d 2035d 0/29 closed as invalid on 2020/01/08 05:33

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P17257
rcu: 	(detected by 1, t=10502 jiffies, g=89697, q=2121 ncpus=2)
task:syz.4.3992      state:R  running task     stack:26632 pid:17257 ppid:16324  flags:0x0000400e
Call Trace:
 <IRQ>
 sched_show_task+0x481/0x5a0 kernel/sched/core.c:9179
 rcu_print_detail_task_stall_rnp kernel/rcu/tree_stall.h:261 [inline]
 print_other_cpu_stall+0xfa7/0x1340 kernel/rcu/tree_stall.h:637
 check_cpu_stall kernel/rcu/tree_stall.h:809 [inline]
 rcu_pending kernel/rcu/tree.c:3950 [inline]
 rcu_sched_clock_irq+0x87c/0x1220 kernel/rcu/tree.c:2295
 update_process_times+0x147/0x1b0 kernel/time/timer.c:2071
 tick_sched_handle kernel/time/tick-sched.c:254 [inline]
 tick_sched_timer+0x3a2/0x580 kernel/time/tick-sched.c:1492
 __run_hrtimer kernel/time/hrtimer.c:1755 [inline]
 __hrtimer_run_queues+0x4df/0xc40 kernel/time/hrtimer.c:1819
 hrtimer_interrupt+0x3c9/0x9c0 kernel/time/hrtimer.c:1881
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1077 [inline]
 __sysvec_apic_timer_interrupt+0xfb/0x3b0 arch/x86/kernel/apic/apic.c:1094
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0x51/0xc0 arch/x86/kernel/apic/apic.c:1088
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:check_kcov_mode kernel/kcov.c:182 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:245 [inline]
RIP: 0010:__sanitizer_cov_trace_switch+0x96/0x120 kernel/kcov.c:350
Code: 41 54 53 48 8b 54 24 20 65 4c 8b 05 34 1f 7e 7e 45 31 c9 eb 08 49 ff c1 4c 39 c8 74 77 4e 8b 54 ce 10 65 44 8b 1d 22 1f 7e 7e <41> 81 e3 00 01 ff 00 74 13 41 81 fb 00 01 00 00 75 d9 41 83 b8 1c
RSP: 0018:ffffc900001f0470 EFLAGS: 00000216
RAX: 0000000000000020 RBX: 000000eea7d3d8a2 RCX: 0000000000000005
RDX: ffffffff81889a9d RSI: ffffffff8cd797a0 RDI: 0000000000000004
RBP: 0000000000000004 R08: ffff8880582cbc00 R09: 000000000000000e
R10: 000000000000000e R11: 0000000000000105 R12: ffff88801ca693d0
R13: f800000000000000 R14: 00000000000003c0 R15: 0000000000048fc4
 check_buffer+0x24d/0x950 kernel/trace/ring_buffer.c:3495
 __rb_reserve_next+0x511/0xd50 kernel/trace/ring_buffer.c:3624
 rb_reserve_next_event kernel/trace/ring_buffer.c:3759 [inline]
 ring_buffer_lock_reserve+0xae1/0xed0 kernel/trace/ring_buffer.c:3818
 __trace_buffer_lock_reserve kernel/trace/trace.c:992 [inline]
 trace_event_buffer_lock_reserve+0x1d0/0x6e0 kernel/trace/trace.c:2902
 trace_event_buffer_reserve+0x29b/0x3c0 kernel/trace/trace_events.c:661
 do_trace_event_raw_event_bpf_trace_printk kernel/trace/bpf_trace.h:11 [inline]
 trace_event_raw_event_bpf_trace_printk+0x101/0x210 kernel/trace/bpf_trace.h:11
 trace_bpf_trace_printk+0x142/0x1a0 kernel/trace/bpf_trace.h:11
 ____bpf_trace_printk kernel/trace/bpf_trace.c:388 [inline]
 bpf_trace_printk+0x11f/0x190 kernel/trace/bpf_trace.c:371
 bpf_prog_9e1c00255e17e72e+0x38/0x3a
 bpf_dispatcher_nop_func include/linux/bpf.h:1213 [inline]
 __bpf_prog_run include/linux/filter.h:612 [inline]
 bpf_prog_run include/linux/filter.h:619 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2322 [inline]
 bpf_trace_run1+0x1c9/0x3b0 kernel/trace/bpf_trace.c:2360
 __bpf_trace_rcu_utilization+0xa2/0xe0 include/trace/events/rcu.h:27
 trace_rcu_utilization+0x179/0x1a0 include/trace/events/rcu.h:27
 rcu_core+0x12d/0x1720 kernel/rcu/tree.c:2439
 handle_softirqs+0x280/0x820 kernel/softirq.c:578
 __do_softirq kernel/softirq.c:612 [inline]
 invoke_softirq kernel/softirq.c:452 [inline]
 __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661
 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
 instr_sysvec_irq_work arch/x86/kernel/irq_work.c:17 [inline]
 sysvec_irq_work+0xa1/0xc0 arch/x86/kernel/irq_work.c:17
 </IRQ>
 <TASK>
 asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:723
RIP: 0010:rcu_read_unlock_special+0x88/0x4c0 kernel/rcu/tree_plugin.h:682
Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 a9 4e 93 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 40 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b
RSP: 0018:ffffc90003877c00 EFLAGS: 00000206
RAX: c214ef79de630300 RBX: 1ffff9200070ef88 RCX: c214ef79de630300
RDX: dffffc0000000000 RSI: ffffffff8aaaba40 RDI: ffffffff8afc6780
RBP: ffffc90003877cf0 R08: ffffffff90da3537 R09: 1ffffffff21b46a6
R10: dffffc0000000000 R11: fffffbfff21b46a7 R12: 0000000000000000
R13: dffffc0000000000 R14: 0000000000000246 R15: ffffffff8cd354d8
 __rcu_read_unlock+0x7c/0xd0 kernel/rcu/tree_plugin.h:426
 rcu_read_unlock+0x85/0xa0 include/linux/rcupdate.h:818
 dput+0xe6/0x1e0 fs/dcache.c:911
 __fput+0x5e5/0x970 fs/file_table.c:392
 task_work_run+0x1ce/0x250 kernel/task_work.c:239
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f80aeb8eb69
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffebb28b5b8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007f80aedb7ba0 RCX: 00007f80aeb8eb69
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f80aedb7ba0 R08: 0000000000000194 R09: 00000016bb28b8af
R10: 00000000003ffc48 R11: 0000000000000246 R12: 00000000000e09bc
R13: 00007ffebb28b6b0 R14: ffffffffffffffff R15: 00007ffebb28b6d0
 </TASK>

Crashes (17):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/08/03 07:09 linux-6.6.y 3a8ababb8b6a 7368264b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in dput
2025/07/30 03:49 linux-6.6.y dbcb8d8e4163 f8f2b4da .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in dput
2025/07/29 17:07 linux-6.6.y dbcb8d8e4163 c4a95487 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in dput
2025/07/28 13:28 linux-6.6.y dbcb8d8e4163 fb8f743d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in dput
2025/07/28 13:28 linux-6.6.y dbcb8d8e4163 fb8f743d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in dput
2025/07/27 23:25 linux-6.6.y dbcb8d8e4163 fb8f743d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in dput
2025/07/26 08:06 linux-6.6.y dbcb8d8e4163 fb8f743d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in dput
2025/07/26 01:07 linux-6.6.y dbcb8d8e4163 fb8f743d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in dput
2025/07/20 15:10 linux-6.6.y d96eb99e2f0e 7117feec .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in dput
2025/07/19 16:43 linux-6.6.y d96eb99e2f0e 7117feec .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in dput
2025/07/14 19:21 linux-6.6.y 9247f4e6573a d8fc7335 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in dput
2025/07/13 01:16 linux-6.6.y 59a2de10b81a 3cda49cf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in dput
2025/07/12 15:24 linux-6.6.y 59a2de10b81a 3cda49cf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in dput
2025/07/09 11:42 linux-6.6.y a5df3a702b2c f4e5e155 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in dput
2025/07/08 07:59 linux-6.6.y a5df3a702b2c 4f67c4ae .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in dput
2025/07/03 10:09 linux-6.6.y 3f5b4c104b7d 115ceea7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in dput
2025/06/17 20:59 linux-6.6.y c2603c511feb e77fae15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in dput
* Struck through repros no longer work on HEAD.