From: syzbot <syzbot+eb74dca0d1eb3ec227a7@syzkaller.appspotmail.com>
To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
mathieu.desnoyers@efficios.com, mhiramat@kernel.org,
rostedt@goodmis.org, syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] [trace?] WARNING in check_buffer
Date: Tue, 06 Oct 2026 14:58:33 -0700 [thread overview]
Message-ID: <6ac56f09.fe639fcc.32b100.000d.GAE@google.com> (raw)
In-Reply-To: <6aafebec.a6af0033.177e91.000d.GAE@google.com>
syzbot has found a reproducer for the following issue on:
HEAD commit: 69f80fef3153 Merge tag 'ata-7.3-rc7' of git://git.kernel.o..
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=1266a715580000
kernel config: https://syzkaller.appspot.com/x/.config?x=fc812281b37d1115
dashboard link: https://syzkaller.appspot.com/bug?extid=eb74dca0d1eb3ec227a7
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
userspace arch: i386
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1666a715580000
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+eb74dca0d1eb3ec227a7@syzkaller.appspotmail.com
0x90: [80897807093] delta:0 TIME EXTEND
0x98: [80897807093] delta:0 .
expected end:0xb0 last event actually ended at:0xb0
------------[ cut here ]------------
system_state != SYSTEM_BOOTING
WARNING: kernel/trace/ring_buffer.c:4783 at check_buffer.cold+0x1a2/0x1ef kernel/trace/ring_buffer.c:4783, CPU#2: syz-executor270/6036
Modules linked in:
CPU: 2 UID: 0 PID: 6036 Comm: syz-executor270 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:check_buffer.cold+0x1a2/0x1ef kernel/trace/ring_buffer.c:4783
Code: 03 0f b6 14 11 38 d0 7c 04 84 d2 75 5c 8b 2d cc 17 22 10 31 ff 89 ee e8 9f 78 e8 00 85 ed 0f 84 18 13 eb 00 e8 22 7e e8 00 90 <0f> 0b 90 e9 c3 10 eb 00 49 c7 c7 00 5e f6 8b e9 51 fe ff ff e8 38
RSP: 0000:ffffc900037cf9a0 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 1ffff920006f9f3a RCX: 0000000000000002
RDX: ffff888021a98000 RSI: ffffffff812327ce RDI: ffff888021a98000
RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000003 R11: 0000000000000001 R12: 0000000000005c85
R13: ffff88801d6c4000 R14: ffff88801cf70000 R15: ffffffff8bf659a0
FS: 0000000000000000(0000) GS:ffff888096b52000(0063) knlGS:00000000f5e91b40
CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 00000000f5e916d8 CR3: 0000000055cc8000 CR4: 0000000000352ef0
Call Trace:
<TASK>
__rb_reserve_next.constprop.0+0x486/0x1640 kernel/trace/ring_buffer.c:4873
rb_reserve_next_event kernel/trace/ring_buffer.c:5010 [inline]
ring_buffer_lock_reserve+0x49a/0x1220 kernel/trace/ring_buffer.c:5069
__trace_buffer_lock_reserve kernel/trace/trace.h:1677 [inline]
write_marker_to_buffer+0x88/0x5f0 kernel/trace/trace.c:5936
tracing_mark_write+0x215/0x3b0 kernel/trace/trace.c:6322
vfs_write+0x2aa/0x1050 fs/read_write.c:685
ksys_write+0x1f8/0x250 fs/read_write.c:739
do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:79 [inline]
do_int80_emulation+0x166/0x650 arch/x86/entry/syscall_32.c:166
asm_int80_emulation+0x1a/0x20 arch/x86/include/asm/idtentry.h:598
RIP: 0023:0xf7ee27eb
Code: 57 56 53 8b 44 24 14 f6 00 08 75 23 8b 44 24 18 8b 5c 24 1c 8b 4c 24 20 8b 54 24 24 8b 74 24 28 8b 7c 24 2c 8b 6c 24 30 cd 80 <5b> 5e 5f 5d c3 5b 5e 5f 5d e9 57 dd ff ff 66 90 66 90 66 90 90 55
RSP: 002b:00000000f5e9161c EFLAGS: 00000246 ORIG_RAX: 0000000000000004
RAX: ffffffffffffffda RBX: 0000000000000007 RCX: 00000000f7f2dde3
RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
</TASK>
----------------
Code disassembly (best guess):
0: 57 push %rdi
1: 56 push %rsi
2: 53 push %rbx
3: 8b 44 24 14 mov 0x14(%rsp),%eax
7: f6 00 08 testb $0x8,(%rax)
a: 75 23 jne 0x2f
c: 8b 44 24 18 mov 0x18(%rsp),%eax
10: 8b 5c 24 1c mov 0x1c(%rsp),%ebx
14: 8b 4c 24 20 mov 0x20(%rsp),%ecx
18: 8b 54 24 24 mov 0x24(%rsp),%edx
1c: 8b 74 24 28 mov 0x28(%rsp),%esi
20: 8b 7c 24 2c mov 0x2c(%rsp),%edi
24: 8b 6c 24 30 mov 0x30(%rsp),%ebp
28: cd 80 int $0x80
* 2a: 5b pop %rbx <-- trapping instruction
2b: 5e pop %rsi
2c: 5f pop %rdi
2d: 5d pop %rbp
2e: c3 ret
2f: 5b pop %rbx
30: 5e pop %rsi
31: 5f pop %rdi
32: 5d pop %rbp
33: e9 57 dd ff ff jmp 0xffffdd8f
38: 66 90 xchg %ax,%ax
3a: 66 90 xchg %ax,%ax
3c: 66 90 xchg %ax,%ax
3e: 90 nop
3f: 55 push %rbp
---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
prev parent reply other threads:[~2026-10-06 21:58 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-20 14:21 [syzbot] [trace?] WARNING in check_buffer syzbot
2026-09-20 20:16 ` Steven Rostedt
2026-10-06 21:58 ` syzbot [this message]
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