WARNING in trace_rb_cpu_prepare

Status: upstream: reported syz repro on 2026/08/01 23:00
Reported-by: syzbot+b8c64aaf011042278a71@syzkaller.appspotmail.com
First crash: 32d, last: 57m
▶ ▼ 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 1512 11m 30d 0/29 upstream: reported syz repro on 2026/08/03 11:32
android-6-12 WARNING in trace_rb_cpu_prepare -1 6 11d 32d 0/1 premoderation: reported on 2026/08/01 06:47
linux-6.6 WARNING in trace_rb_cpu_prepare -1 syz, C 14 16m 32d 0/2 upstream: reported C repro on 2026/08/01 09:59
linux-6.1 WARNING in trace_rb_cpu_prepare -1 syz 22 1d05h 25d 0/3 upstream: reported syz repro on 2026/08/08 09:55

Sample crash report:
------------[ cut here ]------------
failed to allocate ring buffer on CPU 1
WARNING: CPU: 1 PID: 4381 at kernel/trace/ring_buffer.c:5818 trace_rb_cpu_prepare+0x2a6/0x2f0 kernel/trace/ring_buffer.c:5817
Modules linked in:
CPU: 1 PID: 4381 Comm: syz.3.20 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:trace_rb_cpu_prepare+0x2a6/0x2f0 kernel/trace/ring_buffer.c:5817
Code: 48 0f ab 08 31 c0 48 83 c4 30 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 0a 21 fd ff 48 c7 c7 40 2f 2f 8a 8b 74 24 04 e8 2a 7b 39 08 <0f> 0b b8 f4 ff ff ff eb d3 e8 ec 20 fd ff 0f 0b e9 83 fd ff ff e8
RSP: 0018:ffffc9000358fac0 EFLAGS: 00010246
RAX: ea5f4681c1f70e00 RBX: ffff888058b94010 RCX: ffff888028d49dc0
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: ffff88807d3c7078 R08: ffff8880b912795b R09: 1ffff11017224f2b
R10: dffffc0000000000 R11: ffffed1017224f2c R12: 0000000000000000
R13: ffff88802b637588 R14: ffff88802b637588 R15: ffff888058b940b0
FS:  00007f55db6a66c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f55dc093840 CR3: 0000000075c2c000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 cpuhp_invoke_callback+0x481/0x7e0 kernel/cpu.c:201
 cpuhp_issue_call+0x3d3/0x760 kernel/cpu.c:-1
 __cpuhp_state_add_instance_cpuslocked+0x24b/0x6c0 kernel/cpu.c:2020
 __cpuhp_state_add_instance+0x21/0x30 kernel/cpu.c:2041
 cpuhp_state_add_instance include/linux/cpuhotplug.h:391 [inline]
 __ring_buffer_alloc+0x2d2/0x540 kernel/trace/ring_buffer.c:1844
 allocate_trace_buffer kernel/trace/trace.c:9249 [inline]
 allocate_trace_buffers+0x70/0x2c0 kernel/trace/trace.c:9271
 trace_array_create+0x2ac/0xc00 kernel/trace/trace.c:9427
 instance_mkdir+0xc8/0x120 kernel/trace/trace.c:9473
 tracefs_syscall_mkdir+0xb7/0x110 fs/tracefs/inode.c:87
 vfs_mkdir+0x386/0x570 fs/namei.c:4116
 do_mkdirat+0x1dd/0x5c0 fs/namei.c:4141
 __do_sys_mkdirat fs/namei.c:4156 [inline]
 __se_sys_mkdirat fs/namei.c:4154 [inline]
 __x64_sys_mkdirat+0x85/0x90 fs/namei.c:4154
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f55dc046159
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:00007f55db6a6028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f55dc2cdfa0 RCX: 00007f55dc046159
RDX: 00000000000001ff RSI: 0000200000000100 RDI: ffffffffffffff9c
RBP: 00007f55dc0dd024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f55dc2ce038 R14: 00007f55dc2cdfa0 R15: 00007ffd7d778078
 </TASK>

Crashes (17):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/31 00:14 linux-5.15.y 28c35638ec51 2f52988a .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING in trace_rb_cpu_prepare
2026/09/02 22:26 linux-5.15.y 0996e0926f6b 85995287 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING in trace_rb_cpu_prepare
2026/09/02 08:01 linux-5.15.y 28c35638ec51 587f6b29 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING in trace_rb_cpu_prepare
2026/08/31 23:56 linux-5.15.y 28c35638ec51 316d9396 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING in trace_rb_cpu_prepare
2026/08/31 00:01 linux-5.15.y 28c35638ec51 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING in trace_rb_cpu_prepare
2026/08/30 22:38 linux-5.15.y 28c35638ec51 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING in trace_rb_cpu_prepare
2026/08/25 22:03 linux-5.15.y 945fa863f02c a9a1fc32 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING in trace_rb_cpu_prepare
2026/08/25 22:02 linux-5.15.y 945fa863f02c a9a1fc32 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING in trace_rb_cpu_prepare
2026/08/25 08:57 linux-5.15.y 945fa863f02c 614e416a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING in trace_rb_cpu_prepare
2026/08/21 04:57 linux-5.15.y 0eb903b5b519 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING in trace_rb_cpu_prepare
2026/08/20 13:46 linux-5.15.y 0eb903b5b519 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING in trace_rb_cpu_prepare
2026/08/13 14:48 linux-5.15.y aabd761612db 359b2492 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING in trace_rb_cpu_prepare
2026/08/13 09:16 linux-5.15.y aabd761612db 359b2492 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING in trace_rb_cpu_prepare
2026/08/09 04:39 linux-5.15.y aabd761612db 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING in trace_rb_cpu_prepare
2026/08/03 18:40 linux-5.15.y 6e2fd6534337 6b7c9f71 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING in trace_rb_cpu_prepare
2026/08/03 06:21 linux-5.15.y 6e2fd6534337 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING in trace_rb_cpu_prepare
2026/08/01 23:00 linux-5.15.y 6e2fd6534337 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING in trace_rb_cpu_prepare
* Struck through repros no longer work on HEAD.