syzbot
WARNING in trace_rb_cpu_prepare
Status:
upstream: reported on 2026/08/01 09:59
Reported-by: syzbot+59657eaf8add48294429@syzkaller.appspotmail.com
First crash: 5d05h, last: 1d04h
Sample crash report:
------------[ cut here ]------------
failed to allocate ring buffer on CPU 0
WARNING: CPU: 1 PID: 9884 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: 9884 Comm: syz.0.1213 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:ffffc9000b96fab8 EFLAGS: 00010246
RAX: 7ce39e476e077c00 RBX: 0000000000000000 RCX: 0000000000080000
RDX: ffffc9000caf1000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: 0000000000000000 R08: ffff8880b8e28c53 R09: 1ffff110171c518a
R10: dffffc0000000000 R11: ffffed10171c518b R12: 0000000000000000
R13: ffff88802bd6c380 R14: ffff88805d7a8410 R15: ffff88805d7a84b0
FS: 00007fa135eea6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c2a8e17 CR3: 0000000063860000 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: 0033:0x7fa134f9e019
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:00007fa135eea028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007fa135225fa0 RCX: 00007fa134f9e019
RDX: 00000000000001ff RSI: 0000200000000600 RDI: ffffffffffffff9c
RBP: 00007fa13503500c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa135226038 R14: 00007fa135225fa0 R15: 00007fff5dd7b868
</TASK>
* Struck through repros no longer work on HEAD.