syzbot

 sign-in | mailing list | source | docs
🐞 Open [871]
🐞 Fixed [141]
🐞 Invalid [985]
⬇ Missing Backports [73]
≡ Crashes
Kernel Health Bugs/Month Bug Lifetimes Fuzzing
💬 Send us feedback

INFO: rcu detected stall in sys_perf_event_open (2)

Status: upstream: reported C repro on 2024/09/23 05:55
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+5284a86a0b0a31ab266a@syzkaller.appspotmail.com
First crash: 485d, last: 3d10h
Fix commit to backport (bisect log) :
tree: upstream
commit f4bf3ca2e5cba655824b6e0893a98dfb33ed24e5
Author: Lingutla Chandrasekhar <clingutla@codeaurora.org>
Date: Fri Apr 7 23:05:26 2023 +0000

  softirq: Add trace points for tasklet entry/exit

[report pending]
  
▶ ▼ Discussions (2)
Title Replies (including bot) Last reply
Re: [PATCH 6.1] softirq: Add trace points for tasklet entry/exit 3 (3) 2025/08/21 22:05
[PATCH 6.1] softirq: Add trace points for tasklet entry/exit 1 (1) 2025/08/21 18:40
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2025/09/18 linux-6.1.y (ToT) 3db754f56897 C [report] INFO: rcu detected stall in smp_call_function
2025/09/18 upstream (ToT) 86cc796e5e9b C Didn't crash
▶ ▼ Similar bugs (17)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: rcu detected stall in sys_perf_event_open (2) origin:lts-only 1 C error 58 3d22h 743d 0/3 upstream: reported C repro on 2024/01/09 18:19
upstream INFO: rcu detected stall in sys_perf_event_open (3) perf 1 1 2206d 2206d 0/29 closed as invalid on 2020/01/08 05:23
linux-6.6 INFO: rcu detected stall in perf_event_open (2) origin:lts-only 1 C inconclusive 26 3d00h 73d 0/2 upstream: reported C repro on 2025/11/10 01:14
upstream INFO: rcu detected stall in sys_perf_event_open (4) perf 1 1 2205d 2205d 0/29 closed as invalid on 2020/01/09 08:13
upstream INFO: rcu detected stall in sys_perf_event_open (2) perf 1 8 2240d 2242d 0/29 closed as invalid on 2019/12/04 14:14
linux-6.1 INFO: rcu detected stall in sys_perf_event_open 1 1 590d 590d 0/3 auto-obsoleted due to no activity on 2024/09/19 01:45
linux-6.6 INFO: rcu detected stall in perf_event_open 1 C done 4 146d 160d 2/2 fixed on 2025/10/06 10:09
linux-5.15 INFO: rcu detected stall in sys_perf_event_open 1 1 1008d 1008d 0/3 auto-obsoleted due to no activity on 2023/08/17 04:33
upstream INFO: rcu detected stall in sys_perf_event_open perf 1 1 2685d 2683d 0/29 auto-closed as invalid on 2019/03/14 17:19
upstream BUG: soft lockup in perf_event_open (2) kernel 1 2 15d 44d 0/29 moderation: reported on 2025/12/09 01:40
android-5-15 BUG: soft lockup in sys_perf_event_open 1 1 625d 625d 0/2 auto-obsoleted due to no activity on 2024/08/04 07:07
upstream BUG: soft lockup in sys_perf_event_open perf 1 1 601d 597d 0/29 auto-obsoleted due to no activity on 2024/08/29 01:52
upstream BUG: soft lockup in perf_event_open trace bpf 1 2 210d 206d 0/29 auto-obsoleted due to no activity on 2025/09/23 09:29
upstream BUG: soft lockup in sys_perf_event_open (2) kvm fs 1 6 368d 476d 0/29 auto-obsoleted due to no activity on 2025/04/18 04:31
upstream INFO: rcu detected stall in perf_event_open (2) perf 1 1 1577d 1577d 0/29 auto-closed as invalid on 2021/11/26 20:49
upstream INFO: rcu detected stall in perf_event_open kernel 1 1 1674d 1674d 0/29 auto-closed as invalid on 2021/09/21 01:14
upstream INFO: rcu detected stall in __se_sys_perf_event_open perf 1 1 2028d 2028d 0/29 auto-closed as invalid on 2020/10/02 02:08
▶ ▼ Last patch testing requests (1)
Created Duration User Patch Repo Result
2025/08/12 15:47 2h08m sumanth.gavini@yahoo.com patch linux-6.1.y OK log
▶ ▼ Fix bisection attempts (1)
Created Duration User Patch Repo Result
2024/12/03 12:42 7h31m fix candidate upstream OK (1) job log

Sample crash report:
rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 1-.... } 2660 jiffies s: 27333 root: 0x2/.
rcu: blocking rcu_node structures (internal RCU debug):
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 18384 Comm: syz.3.6278 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:asm_sysvec_irq_work+0x0/0x20 arch/x86/include/asm/idtentry.h:722
Code: e9 b5 03 00 00 90 90 90 90 90 0f 01 ca fc 6a ff e8 b5 02 00 00 48 89 c4 48 89 e7 e8 9a 6e ea ff e9 95 03 00 00 90 90 90 90 90 <0f> 01 ca fc 6a ff e8 95 02 00 00 48 89 c4 48 89 e7 e8 6a 73 ea ff
RSP: 0018:ffffc900001e0958 EFLAGS: 00000006
RAX: 3a9083a904e5ea00 RBX: 1ffff9200003c138 RCX: 3a9083a904e5ea00
RDX: dffffc0000000000 RSI: ffffffff8a8c0620 RDI: ffffffff8adf0020
RBP: ffffc900001e0a80 R08: ffffffff90ad832f R09: 1ffffffff215b065
R10: dffffc0000000000 R11: fffffbfff215b066 R12: 0000000000000246
R13: dffffc0000000000 R14: ffff8880b8f3b900 R15: 0000000000000002
FS:  00007f5c3fbfe6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000004 CR3: 000000002ed20000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
RIP: 0010:rcu_read_unlock_special+0x7f/0x510 kernel/rcu/tree_plugin.h:685
Code: eb 03 48 b8 f1 f1 f1 f1 f8 f2 f2 f2 4a 89 04 2b 42 c7 44 2b 08 f8 f3 f3 f3 65 44 8b 35 92 50 95 7e 41 f7 c6 00 00 f0 00 74 40 <48> c7 44 24 40 0e 36 e0 45 4a c7 04 2b 00 00 00 00 42 c7 44 2b 08
RSP: 0018:ffffc900001e0980 EFLAGS: 00000206
 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:426
 rcu_read_unlock include/linux/rcupdate.h:823 [inline]
 hsr_announce+0x2ca/0x340 net/hsr/hsr_device.c:407
 call_timer_fn+0x1ac/0x670 kernel/time/timer.c:1701
 expire_timers kernel/time/timer.c:1752 [inline]
 __run_timers+0x53e/0x800 kernel/time/timer.c:2023
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:2036
 handle_softirqs+0x2a1/0x930 kernel/softirq.c:596
 __do_softirq kernel/softirq.c:630 [inline]
 invoke_softirq kernel/softirq.c:470 [inline]
 __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:679
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:691
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:__bad_area_nosemaphore+0x1d/0x750 arch/x86/mm/fault.c:793
Code: 00 5b 41 5e 41 5f eb 05 0f 1f 44 00 00 55 48 89 e5 41 57 41 56 41 55 41 54 53 48 83 e4 e0 48 81 ec c0 00 00 00 44 89 44 24 4c <89> 4c 24 48 48 89 54 24 30 49 89 f4 49 89 fe 65 48 8b 04 25 28 00
RSP: 0018:ffffc900044a7b40 EFLAGS: 00000282
RAX: ffffffff813969c3 RBX: ffffc900044a7c88 RCX: 0000000000000000
RDX: 0000000000000004 RSI: 0000000000000000 RDI: ffffc900044a7c88
RBP: ffffc900044a7c40 R08: 0000000000000001 R09: 1ffff1100e49c1fd
R10: dffffc0000000000 R11: ffffed100e49c1fe R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000004
 handle_page_fault arch/x86/mm/fault.c:1431 [inline]
 exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1487
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:608
RIP: 0010:__get_user_4+0x1c/0x30 arch/x86/lib/getuser.S:85
Code: 01 ca c3 90 90 90 90 90 90 90 90 90 90 90 48 ba fd ef ff ff ff 7f 00 00 48 39 d0 0f 83 90 00 00 00 48 19 d2 48 21 d0 0f 01 cb <8b> 10 31 c0 0f 01 ca c3 90 90 90 90 90 90 90 90 90 90 90 90 48 ba
RSP: 0018:ffffc900044a7d38 EFLAGS: 00050202
RAX: 0000000000000004 RBX: ffffc900044a7e20 RCX: 3a9083a904e5ea00
RDX: ffffffffffffffff RSI: ffffffff8a8c17a0 RDI: ffffffff8adf0020
RBP: ffffc900044a7f10 R08: ffffffff8e1f482f R09: 1ffffffff1c3e905
R10: dffffc0000000000 R11: fffffbfff1c3e906 R12: 0000000000000000
R13: 0000000000000004 R14: dffffc0000000000 R15: 0000000000000000
 perf_copy_attr+0x45/0x850 kernel/events/core.c:12059
 __do_sys_perf_event_open kernel/events/core.c:12400 [inline]
 __se_sys_perf_event_open+0xf5/0x1ec0 kernel/events/core.c:12378
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f5c4059acb9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f5c3fbfe028 EFLAGS: 00000246 ORIG_RAX: 000000000000012a
RAX: ffffffffffffffda RBX: 00007f5c40815fa0 RCX: 00007f5c4059acb9
RDX: ffffffffffffffff RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f5c40608bf7 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5c40816038 R14: 00007f5c40815fa0 R15: 00007ffc5ce59ea8
 </TASK>

Crashes (31):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/18 16:29 linux-6.1.y cd9b81672742 20d37d28 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in perf_event_open
2025/11/28 11:38 linux-6.1.y f6e38ae624cf d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in perf_event_open
2025/11/26 08:09 linux-6.1.y f6e38ae624cf 64219f15 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in perf_event_open
2025/11/22 14:20 linux-6.1.y f6e38ae624cf 4fb8ef37 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in perf_event_open
2025/09/09 04:26 linux-6.1.y 28c695c365e1 d291dd2d .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in perf_event_open
2025/02/28 09:23 linux-6.1.y 3a8358583626 6a8fcbc4 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in sys_perf_event_open
2024/11/22 03:43 linux-6.1.y b67dc5c9ade9 4b25d554 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in sys_perf_event_open
2025/11/10 11:23 linux-6.1.y f6e38ae624cf 4e1406b4 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in perf_event_open
2025/10/18 08:51 linux-6.1.y c2fda4b3f577 1c8c8cd8 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in perf_event_open
2025/10/14 22:18 linux-6.1.y 882efbdd9d34 b6605ba8 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in perf_event_open
2025/10/06 09:44 linux-6.1.y 882efbdd9d34 49379ee0 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in perf_event_open
2025/09/27 10:08 linux-6.1.y 7b34dc04e4ff 001c9061 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in perf_event_open
2025/09/14 01:11 linux-6.1.y 3db754f56897 e2beed91 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in perf_event_open
2025/08/16 16:05 linux-6.1.y 0bc96de781b4 1804e95e .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in perf_event_open
2025/08/10 03:31 linux-6.1.y 3594f306da12 32a0e5ed .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in perf_event_open
2025/07/11 06:25 linux-6.1.y dfc486ec9cce 3cda49cf .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in perf_event_open
2025/01/12 02:40 linux-6.1.y c63962be84ef 6dbc6a9b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in sys_perf_event_open
2024/09/23 05:54 linux-6.1.y e526b12bf916 6f888b75 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in sys_perf_event_open
2026/01/07 12:27 linux-6.1.y 50cbba13faa2 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in perf_event_open
2025/12/04 10:48 linux-6.1.y f6e38ae624cf d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in perf_event_open
2025/11/26 10:22 linux-6.1.y f6e38ae624cf 64219f15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in perf_event_open
2025/11/17 14:44 linux-6.1.y f6e38ae624cf ef766cd7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in perf_event_open
2025/11/03 02:47 linux-6.1.y f6e38ae624cf 2c50b6a9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in perf_event_open
2025/10/26 12:06 linux-6.1.y 8e6e2188d949 c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in perf_event_open
2025/10/14 14:28 linux-6.1.y 882efbdd9d34 b6605ba8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in perf_event_open
2025/10/03 15:05 linux-6.1.y 882efbdd9d34 49379ee0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in perf_event_open
2025/09/22 09:04 linux-6.1.y 363a599da6d9 67c37560 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in perf_event_open
2025/09/21 00:25 linux-6.1.y 363a599da6d9 67c37560 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in perf_event_open
2025/09/19 22:03 linux-6.1.y 363a599da6d9 67c37560 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in perf_event_open
2025/09/02 12:41 linux-6.1.y f89b6e15694c 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in perf_event_open
2025/08/10 01:37 linux-6.1.y 3594f306da12 32a0e5ed .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in perf_event_open
* Struck through repros no longer work on HEAD.