WARNING in trace_rb_cpu_prepare

Status: upstream: reported on 2026/08/01 09:59
Reported-by: syzbot+59657eaf8add48294429@syzkaller.appspotmail.com
First crash: 13d, last: 5d21h
Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING in trace_rb_cpu_prepare prio:low trace -1 syz 616 47m 10d 0/29 upstream: reported syz repro on 2026/08/03 11:32
android-6-12 WARNING in trace_rb_cpu_prepare -1 4 11h23m 13d 0/1 premoderation: reported on 2026/08/01 06:47
linux-5.15 WARNING in trace_rb_cpu_prepare -1 6 20h27m 12d 0/3 upstream: reported on 2026/08/01 23:00
linux-6.1 WARNING in trace_rb_cpu_prepare -1 5 21h04m 6d01h 0/3 upstream: reported on 2026/08/08 09:55

Sample crash report:
------------[ cut here ]------------
failed to allocate ring buffer on CPU 1
WARNING: CPU: 1 PID: 7330 at kernel/trace/ring_buffer.c:5864 trace_rb_cpu_prepare+0x2fa/0x330 kernel/trace/ring_buffer.c:5863
Modules linked in:
CPU: 1 PID: 7330 Comm: syz.4.314 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:trace_rb_cpu_prepare+0x2fa/0x330 kernel/trace/ring_buffer.c:5863
Code: 00 f0 48 0f ab 2b 31 c0 48 83 c4 38 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 24 01 fd ff 48 c7 c7 a0 ee ce 8a 89 de e8 c6 ce c6 ff <0f> 0b b8 f4 ff ff ff eb d5 e8 08 01 fd ff e9 32 ff ff ff e8 fe 00
RSP: 0018:ffffc9000471fab8 EFLAGS: 00010246
RAX: 37f353d9a3efd300 RBX: 0000000000000001 RCX: 0000000000080000
RDX: ffffc9000e78f000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: 0000000000000001 R08: ffff8880b8e28c53 R09: 1ffff110171c518a
R10: dffffc0000000000 R11: ffffed10171c518b R12: 0000000000000000
R13: ffff88802e770008 R14: ffff88805cd26010 R15: ffff88805cd260b0
FS:  00007f65ac7d76c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7ca30cf8b0 CR3: 00000000258b1000 CR4: 00000000003506e0
Call Trace:
 <TASK>
 cpuhp_invoke_callback+0x481/0x7e0 kernel/cpu.c:205
 cpuhp_issue_call+0x3ed/0x740 kernel/cpu.c:-1
 __cpuhp_state_add_instance_cpuslocked+0x22a/0x570 kernel/cpu.c:2460
 __cpuhp_state_add_instance+0x25/0x40 kernel/cpu.c:2481
 cpuhp_state_add_instance include/linux/cpuhotplug.h:396 [inline]
 __ring_buffer_alloc+0x30e/0x550 kernel/trace/ring_buffer.c:1866
 allocate_trace_buffer kernel/trace/trace.c:9282 [inline]
 allocate_trace_buffers+0x70/0x290 kernel/trace/trace.c:9314
 trace_array_create_systems+0x311/0xc70 kernel/trace/trace.c:9460
 trace_array_create kernel/trace/trace.c:9497 [inline]
 instance_mkdir+0xd1/0x130 kernel/trace/trace.c:9512
 tracefs_syscall_mkdir+0x128/0x1a0 fs/tracefs/inode.c:139
 vfs_mkdir+0x2a5/0x470 fs/namei.c:4168
 do_mkdirat+0x1dc/0x450 fs/namei.c:4191
 __do_sys_mkdirat fs/namei.c:4206 [inline]
 __se_sys_mkdirat fs/namei.c:4204 [inline]
 __x64_sys_mkdirat+0x89/0xa0 fs/namei.c:4204
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f65ab99e0d9
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:00007f65ac7d7028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f65abc26090 RCX: 00007f65ab99e0d9
RDX: 00000000000001ff RSI: 0000200000000140 RDI: ffffffffffffff9c
RBP: 00007f65aba35024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f65abc26128 R14: 00007f65abc26090 R15: 00007ffe63287348
 </TASK>

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/08 13:16 linux-6.6.y 6436c12a2ced 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in trace_rb_cpu_prepare
2026/08/05 11:02 linux-6.6.y aa0e49877a2e 52aa2820 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in trace_rb_cpu_prepare
2026/08/04 22:14 linux-6.6.y aa0e49877a2e d4abbeac .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in trace_rb_cpu_prepare
2026/08/01 09:59 linux-6.6.y a1153c0deb44 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in trace_rb_cpu_prepare
* Struck through repros no longer work on HEAD.