syzbot


INFO: rcu detected stall in unwind_next_frame (5)

Status: upstream: reported syz repro on 2025/10/14 01:28
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+0f5d9b52b3f467f78d36@syzkaller.appspotmail.com
First crash: 242d, last: 4d23h
Cause bisection: failed (error log, bisect log)
  
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [fs?] INFO: rcu detected stall in unwind_next_frame (5) 0 (1) 2025/10/14 01:28
Similar bugs (7)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in unwind_next_frame (2) kernel 1 1 781d 781d 0/29 auto-obsoleted due to no activity on 2023/10/24 10:24
linux-6.1 INFO: rcu detected stall in unwind_next_frame (2) 1 1 567d 567d 0/3 auto-obsoleted due to no activity on 2024/07/04 19:31
upstream INFO: rcu detected stall in unwind_next_frame (3) kernel 1 1 714d 714d 0/29 auto-obsoleted due to no activity on 2024/01/29 09:37
linux-6.1 INFO: rcu detected stall in unwind_next_frame 1 1 732d 732d 0/3 auto-obsoleted due to no activity on 2024/01/21 04:23
upstream INFO: rcu detected stall in unwind_next_frame (4) mm 1 7 352d 485d 0/29 auto-obsoleted due to no activity on 2025/01/25 06:35
linux-5.15 INFO: rcu detected stall in unwind_next_frame 1 1 52d 52d 0/3 upstream: reported on 2025/08/23 20:02
upstream INFO: rcu detected stall in unwind_next_frame kernel 1 2 2703d 2707d 8/29 fixed on 2018/07/09 18:05

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (1 GPs behind) idle=8e14/1/0x4000000000000000 softirq=18748/18750 fqs=1
rcu: 	(detected by 1, t=10502 jiffies, g=12053, q=759 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 5982 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:memset_orig+0x75/0xb0 arch/x86/lib/memset_64.S:92
Code: 89 47 30 48 89 47 38 48 8d 7f 40 75 d8 0f 1f 84 00 00 00 00 00 89 d1 83 e1 38 74 14 c1 e9 03 66 0f 1f 44 00 00 ff c9 48 89 07 <48> 8d 7f 08 75 f5 83 e2 07 74 0a ff ca 88 07 48 8d 7f 01 75 f6 4c
RSP: 0018:ffffc90000007c80 EFLAGS: 00000002
RAX: 0000000000000000 RBX: ffff888056c2a340 RCX: 0000000000000001
RDX: 0000000000000010 RSI: 0000000000000000 RDI: ffffc90000007ca0
RBP: 0000000000000000 R08: ffffc90000007caf R09: 0000000000000000
R10: ffffc90000007ca0 R11: fffff52000000f96 R12: dffffc0000000000
R13: dffffc0000000000 R14: ffffffff8b6cf420 R15: ffff8880b8627bc0
FS:  000055558512b500(0000) GS:ffff888125d3b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffba57b3000 CR3: 000000003058e000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 debug_object_activate+0x38/0x420 lib/debugobjects.c:806
 debug_hrtimer_activate kernel/time/hrtimer.c:438 [inline]
 debug_activate kernel/time/hrtimer.c:477 [inline]
 enqueue_hrtimer+0x30/0x3a0 kernel/time/hrtimer.c:1081
 __run_hrtimer kernel/time/hrtimer.c:1794 [inline]
 __hrtimer_run_queues+0x656/0xc60 kernel/time/hrtimer.c:1841
 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline]
 __sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1058
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
 sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1052
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_acquire+0x175/0x360 kernel/locking/lockdep.c:5872
Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 6b ec f1 10 <48> 3b 44 24 58 0f 85 f2 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e
RSP: 0018:ffffc90003987818 EFLAGS: 00000206
RAX: 0b2e9023536a4b00 RBX: 0000000000000000 RCX: 0b2e9023536a4b00
RDX: 0000000000000001 RSI: ffffffff8d9c68ab RDI: ffffffff8bc03b60
RBP: ffffffff8172ad05 R08: 0000000000000000 R09: ffffffff8172ad05
R10: ffffc900039879d8 R11: ffffffff81ab4450 R12: 0000000000000002
R13: ffffffff8e13a960 R14: 0000000000000000 R15: 0000000000000246
 rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 rcu_read_lock include/linux/rcupdate.h:841 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1169 [inline]
 unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:243 [inline]
 __kasan_slab_free+0x5b/0x80 mm/kasan/common.c:275
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2422 [inline]
 slab_free mm/slub.c:4695 [inline]
 kmem_cache_free+0x18f/0x400 mm/slub.c:4797
 file_free fs/file_table.c:71 [inline]
 __fput+0x6c2/0xa70 fs/file_table.c:481
 fput_close_sync+0x119/0x200 fs/file_table.c:573
 __do_sys_close fs/open.c:1587 [inline]
 __se_sys_close fs/open.c:1572 [inline]
 __x64_sys_close+0x7f/0x110 fs/open.c:1572
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ffba558db2a
Code: 48 3d 00 f0 ff ff 77 48 c3 0f 1f 80 00 00 00 00 48 83 ec 18 89 7c 24 0c e8 43 91 02 00 8b 7c 24 0c 89 c2 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 36 89 d7 89 44 24 0c e8 a3 91 02 00 8b 44 24
RSP: 002b:00007fffa7a45e40 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007ffba558db2a
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 0000000000000003 R08: 00007fffa7a4578c R09: 0079746972756365
R10: 00007fffa7a457f0 R11: 0000000000000293 R12: 0000000000000000
R13: 00007ffba57b1280 R14: 0000000000000003 R15: 00007fffa7a45ef0
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10499 jiffies! g12053 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=8549
rcu: rcu_preempt kthread starved for 10500 jiffies! g12053 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0
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:26760 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5325 [inline]
 __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
 __schedule_loop kernel/sched/core.c:7011 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:7026
 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x4b9/0x870 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
2025/10/10 01:13 net-next 07fdad3a9375 7e2882b3 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: rcu detected stall in unwind_next_frame
2025/09/23 00:01 upstream 07e27ad16399 0ac7291c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in unwind_next_frame
2025/08/24 08:34 upstream 8d245acc1e88 bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in unwind_next_frame
2025/08/21 21:53 upstream 32b7144f806e 0b9605c8 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in unwind_next_frame
2025/07/08 11:54 upstream d7b8f8e20813 4f67c4ae .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in unwind_next_frame
2025/06/30 08:08 upstream d0b3b7b22dfa fc9d8ee5 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in unwind_next_frame
2025/06/26 18:04 upstream ee88bddf7f2f 26d77996 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in unwind_next_frame
2025/06/21 06:19 upstream 11313e2f7812 d6cdfb8a .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in unwind_next_frame
2025/06/17 11:54 upstream 9afe652958c3 417d98fa .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in unwind_next_frame
2025/05/21 17:11 upstream 4a95bc121ccd dc5d3808 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in unwind_next_frame
2025/05/05 10:58 upstream 92a09c47464d b0714e37 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in unwind_next_frame
2025/04/27 14:22 upstream 5bc1018675ec c6b4fb39 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in unwind_next_frame
2025/04/18 14:58 upstream fc96b232f8e7 2a20f901 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in unwind_next_frame
2025/02/14 04:50 upstream ab68d7eb7b1a d9a046cf .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in unwind_next_frame
2025/08/22 02:49 linux-next 7fa4d8dc380f bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: rcu detected stall in unwind_next_frame
2025/04/03 00:31 bpf-next 0a87d6bb6fd2 996a9618 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-bpf-next-kasan-gce BUG: soft lockup in unwind_next_frame
* Struck through repros no longer work on HEAD.