WARNING in trace_rb_cpu_prepare

Status: upstream: reported C repro on 2026/08/03 11:32
Subsystems: trace
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+fbe07bcf949966f3c00f@syzkaller.appspotmail.com
First crash: 99d, last: 1h26m
Cause bisection: the cause commit could be any of (bisect log):
  6a80838814ee tracing: Add show_event_triggers to expose active event triggers
  729757b96a66 tracing: Add show_event_filters to expose active event filters
  e4ef389e761b tracing: Check the return value of tracing_update_buffers()
  
▶ ▼ ✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
e96a8265 assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ WARNING in trace_rb_cpu_prepare 2026/08/01 00:00 2026/08/01 00:00 2026/08/01 00:26 7664cf44
▶ ▼ Discussions (2)
Title Replies (including bot) Last reply
[PATCH] ring-buffer: Do not WARN when trace_rb_cpu_prepare() fails to allocate 1 (1) 2026/11/04 22:25
[syzbot] [trace?] WARNING in trace_rb_cpu_prepare 1 (4) 2026/09/08 07:56
▶ ▼ Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-6-12 WARNING in trace_rb_cpu_prepare -1 7 15d 97d 0/1 premoderation: reported on 2026/08/01 06:47
linux-5.15 WARNING in trace_rb_cpu_prepare -1 syz 54 38m 96d 0/3 upstream: reported syz repro on 2026/08/01 23:00
linux-6.6 WARNING in trace_rb_cpu_prepare origin:lts-only -1 syz, C 45 2d05h 97d 0/2 upstream: reported C repro on 2026/08/01 09:59
linux-6.1 WARNING in trace_rb_cpu_prepare origin:upstream -1 syz, C 58 37m 90d 0/3 upstream: reported C repro on 2026/08/08 09:55
▶ ▼ Cause bisection attempts (3)
Created Duration User Patch Repo Result
2026/09/05 02:20 10h52m bisect upstream OK (3) job log
2026/08/26 18:37 0m bisect upstream error
2026/08/09 14:24 0m bisect upstream error

Sample crash report:
------------[ cut here ]------------
failed to allocate ring buffer on CPU 1
WARNING: kernel/trace/ring_buffer.c:8103 at trace_rb_cpu_prepare+0x330/0x3c0 kernel/trace/ring_buffer.c:8102, CPU#0: syz.2.31/6050
Modules linked in:
CPU: 0 UID: 0 PID: 6050 Comm: syz.2.31 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:trace_rb_cpu_prepare+0x332/0x3c0 kernel/trace/ring_buffer.c:8102
Code: 08 f0 48 0f ab 03 31 c0 48 83 c4 30 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc e8 87 2e fc ff 48 8d 3d 40 36 eb 0d 89 ee <67> 48 0f b9 3a b8 f4 ff ff ff eb d2 e8 6d 2e fc ff e9 ef fe ff ff
RSP: 0018:ffffc90004a377d0 EFLAGS: 00010293
RAX: ffffffff81ca5f89 RBX: dffffc0000000000 RCX: ffff888027b3be80
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffffff8fb595d0
RBP: 0000000000000001 R08: ffffffff8fb1e77f R09: 1ffffffff1f63cef
R10: dffffc0000000000 R11: fffffbfff1f63cf0 R12: 0000000000000000
R13: ffff88803e2a2908 R14: ffff88805d68b0a0 R15: 0000000000000000
FS:  00007f1a0c90e6c0(0000) GS:ffff888125bd1000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555867aea68 CR3: 000000002b852000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 cpuhp_invoke_callback+0x498/0x810 kernel/cpu.c:204
 cpuhp_issue_call+0x3f0/0x750 kernel/cpu.c:-1
 __cpuhp_state_add_instance_cpuslocked+0x225/0x560 kernel/cpu.c:2423
 __cpuhp_state_add_instance+0x25/0x40 kernel/cpu.c:2444
 cpuhp_state_add_instance include/linux/cpuhotplug.h:383 [inline]
 alloc_buffer+0x188f/0x1d70 kernel/trace/ring_buffer.c:2917
 __ring_buffer_alloc+0x2c/0x40 kernel/trace/ring_buffer.c:2959
 allocate_trace_buffer+0x1d2/0x950 kernel/trace/trace.c:8465
 allocate_trace_buffers kernel/trace/trace.c:8498 [inline]
 trace_array_create_systems+0x590/0xe60 kernel/trace/trace.c:8676
 trace_array_create kernel/trace/trace.c:8719 [inline]
 instance_mkdir+0xd5/0x140 kernel/trace/trace.c:8734
 tracefs_syscall_mkdir+0x11a/0x190 fs/tracefs/inode.c:121
 vfs_mkdir+0x408/0x620 fs/namei.c:5410
 filename_mkdirat+0x289/0x520 fs/namei.c:5443
 __do_sys_mkdirat fs/namei.c:5464 [inline]
 __se_sys_mkdirat+0x35/0x150 fs/namei.c:5461
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1a0d2ae159
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:00007f1a0c90e028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f1a0d535fa0 RCX: 00007f1a0d2ae159
RDX: 00000000000001ff RSI: 0000200000000140 RDI: ffffffffffffff9c
RBP: 00007f1a0d345024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1a0d536038 R14: 00007f1a0d535fa0 R15: 00007ffc0a111b18
 </TASK>
----------------
Code disassembly (best guess):
   0:	08 f0                	or     %dh,%al
   2:	48 0f ab 03          	bts    %rax,(%rbx)
   6:	31 c0                	xor    %eax,%eax
   8:	48 83 c4 30          	add    $0x30,%rsp
   c:	5b                   	pop    %rbx
   d:	41 5c                	pop    %r12
   f:	41 5d                	pop    %r13
  11:	41 5e                	pop    %r14
  13:	41 5f                	pop    %r15
  15:	5d                   	pop    %rbp
  16:	c3                   	ret
  17:	cc                   	int3
  18:	cc                   	int3
  19:	cc                   	int3
  1a:	cc                   	int3
  1b:	cc                   	int3
  1c:	e8 87 2e fc ff       	call   0xfffc2ea8
  21:	48 8d 3d 40 36 eb 0d 	lea    0xdeb3640(%rip),%rdi        # 0xdeb3668
  28:	89 ee                	mov    %ebp,%esi
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	b8 f4 ff ff ff       	mov    $0xfffffff4,%eax
  34:	eb d2                	jmp    0x8
  36:	e8 6d 2e fc ff       	call   0xfffc2ea8
  3b:	e9 ef fe ff ff       	jmp    0xffffff2f

Crashes (4401):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/08 07:55 upstream 28924df2a08f 680aa3e1 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in trace_rb_cpu_prepare
2026/09/04 05:16 upstream 8ab1afb2eb24 801f0966 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in trace_rb_cpu_prepare
2026/08/11 22:22 upstream d58772d8520c 37a258dd .config console log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root WARNING in trace_rb_cpu_prepare
2026/08/06 07:37 upstream 0d8395707651 cd5b1963 .config strace log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci2-upstream-fs WARNING in trace_rb_cpu_prepare
2026/08/06 06:38 upstream 0d8395707651 cd5b1963 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in trace_rb_cpu_prepare
2026/09/23 11:32 upstream fe2ec83746e5 abce1216 .config console log report syz / log [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in trace_rb_cpu_prepare
2026/08/19 23:42 upstream bd5f485f3f02 1e72964b .config console log report syz / log [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in trace_rb_cpu_prepare
2026/09/02 14:02 upstream 89a312991dc6 74e93e68 .config console log report syz / log [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in trace_rb_cpu_prepare
2026/11/06 02:08 linux-next ddfe51b0a0f5 5cecaf1f .config strace log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in trace_rb_cpu_prepare
2026/10/26 09:29 linux-next 20a33c6b6cbe 1d9ca40b .config console log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in trace_rb_cpu_prepare
2026/11/06 16:13 upstream f66469d9905b 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in trace_rb_cpu_prepare
2026/11/06 11:20 upstream d68ce4e71248 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root WARNING in trace_rb_cpu_prepare
2026/11/06 10:56 upstream d68ce4e71248 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in trace_rb_cpu_prepare
2026/11/06 09:51 upstream d68ce4e71248 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in trace_rb_cpu_prepare
2026/11/06 07:24 upstream d68ce4e71248 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in trace_rb_cpu_prepare
2026/11/06 06:26 upstream d68ce4e71248 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in trace_rb_cpu_prepare
2026/11/06 05:16 upstream d68ce4e71248 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in trace_rb_cpu_prepare
2026/11/05 23:41 upstream 05441d697f7f 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in trace_rb_cpu_prepare
2026/11/05 20:52 upstream 05441d697f7f 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in trace_rb_cpu_prepare
2026/11/05 19:36 upstream 05441d697f7f 2ee8459f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in trace_rb_cpu_prepare
2026/11/05 19:29 upstream 05441d697f7f 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root WARNING in trace_rb_cpu_prepare
2026/11/05 18:21 upstream 05441d697f7f 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root WARNING in trace_rb_cpu_prepare
2026/11/05 15:25 upstream 05441d697f7f 2ee8459f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in trace_rb_cpu_prepare
2026/11/05 11:50 upstream 05441d697f7f 2ee8459f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root WARNING in trace_rb_cpu_prepare
2026/11/05 08:33 upstream 05441d697f7f 2ee8459f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in trace_rb_cpu_prepare
2026/11/05 08:01 upstream 05441d697f7f 2ee8459f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in trace_rb_cpu_prepare
2026/11/05 04:40 upstream 05441d697f7f 2ee8459f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root WARNING in trace_rb_cpu_prepare
2026/11/05 03:17 upstream 05441d697f7f 73438ed0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in trace_rb_cpu_prepare
2026/11/04 19:17 upstream 05441d697f7f 5af5b6c6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root WARNING in trace_rb_cpu_prepare
2026/11/04 17:30 upstream 05441d697f7f 73438ed0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in trace_rb_cpu_prepare
2026/11/04 16:29 upstream 05441d697f7f 5af5b6c6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root WARNING in trace_rb_cpu_prepare
2026/11/04 11:05 upstream 05441d697f7f 5af5b6c6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in trace_rb_cpu_prepare
2026/11/04 09:49 upstream 05441d697f7f 5af5b6c6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root WARNING in trace_rb_cpu_prepare
2026/11/04 06:33 upstream 05441d697f7f 5af5b6c6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in trace_rb_cpu_prepare
2026/11/04 04:36 upstream 05441d697f7f 5af5b6c6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in trace_rb_cpu_prepare
2026/11/04 03:02 upstream 05441d697f7f d02c3949 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in trace_rb_cpu_prepare
2026/11/04 02:13 upstream 05441d697f7f d02c3949 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in trace_rb_cpu_prepare
2026/11/04 01:03 upstream 05441d697f7f e2d35131 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in trace_rb_cpu_prepare
2026/11/03 23:48 upstream 05441d697f7f d02c3949 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root WARNING in trace_rb_cpu_prepare
2026/11/03 21:42 upstream 05441d697f7f d02c3949 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in trace_rb_cpu_prepare
2026/11/03 18:11 upstream 05441d697f7f e2d35131 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in trace_rb_cpu_prepare
2026/11/03 14:33 upstream 6628e7d4c6b2 e2d35131 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in trace_rb_cpu_prepare
2026/11/03 06:40 upstream 6628e7d4c6b2 0a94d799 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in trace_rb_cpu_prepare
2026/11/03 05:40 upstream 6628e7d4c6b2 0a94d799 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root WARNING in trace_rb_cpu_prepare
2026/08/03 11:29 upstream 075b74841bd0 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in trace_rb_cpu_prepare
2026/07/31 20:11 upstream 8ba098e6b6ff 7664cf44 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in trace_rb_cpu_prepare
2026/07/30 11:27 upstream 11028ab62899 2377cd3d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in trace_rb_cpu_prepare
2026/11/05 16:45 upstream 05441d697f7f 5cecaf1f .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in trace_rb_cpu_prepare
2026/11/06 16:35 upstream f66469d9905b 5cecaf1f .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in trace_rb_cpu_prepare
2026/11/06 14:38 upstream f66469d9905b 5cecaf1f .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in trace_rb_cpu_prepare
2026/11/06 13:13 upstream f66469d9905b 5cecaf1f .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in trace_rb_cpu_prepare
2026/11/06 08:43 linux-next ddfe51b0a0f5 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in trace_rb_cpu_prepare
2026/11/06 01:05 linux-next ddfe51b0a0f5 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in trace_rb_cpu_prepare
2026/11/05 13:02 linux-next 8b7179210b22 2ee8459f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in trace_rb_cpu_prepare
2026/11/05 10:05 linux-next 8b7179210b22 2ee8459f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in trace_rb_cpu_prepare
2026/11/05 06:56 linux-next 8b7179210b22 2ee8459f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in trace_rb_cpu_prepare
2026/11/04 15:04 linux-next d6bcfc94eb4d 5af5b6c6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in trace_rb_cpu_prepare
2026/11/03 12:41 linux-next 2637bdec0535 0a94d799 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in trace_rb_cpu_prepare
2026/11/03 12:19 linux-next 2637bdec0535 0a94d799 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in trace_rb_cpu_prepare
2026/11/03 08:28 linux-next 2637bdec0535 0a94d799 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in trace_rb_cpu_prepare
2026/11/03 03:57 linux-next 2637bdec0535 0a94d799 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in trace_rb_cpu_prepare
2026/11/03 02:34 linux-next 2637bdec0535 0a94d799 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in trace_rb_cpu_prepare
2026/10/16 09:32 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7a19f0cc94ad 3f2522c6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in trace_rb_cpu_prepare
2026/10/11 21:31 git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux.git for-next a5ae1bf65cee 4f92358f .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-riscv64 WARNING in trace_rb_cpu_prepare
2026/09/27 20:37 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master 73ae59e97596 a3c7249d .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-compat WARNING in trace_rb_cpu_prepare
* Struck through repros no longer work on HEAD.