[v6.1] WARNING in trace_check_vprintf

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: dc5c83b7f5f8 Linux 6.1.178
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1167f2ea580000
kernel config: https://syzkaller.appspot.com/x/.config?x=31dfefc4a14efea3
dashboard link: https://syzkaller.appspot.com/bug?extid=ae301276c89ae21db82a
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a9aa438e39c2/disk-dc5c83b7.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a7b5afd2e170/vmlinux-dc5c83b7.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3c7673d370fb/bzImage-dc5c83b7.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ae3012...@syzkaller.appspotmail.com

------------[ cut here ]------------
fmt: 'level=%s
' current_buffer: ' <idle>-0 [000] ..... 94.756238: initcall_level: level='
WARNING: CPU: 1 PID: 4646 at kernel/trace/trace.c:3891 trace_check_vprintf+0xd4a/0x1080 kernel/trace/trace.c:3889
Modules linked in:
CPU: 1 PID: 4646 Comm: syz.4.86 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:trace_check_vprintf+0xd4a/0x1080 kernel/trace/trace.c:3889
Code: e8 db 24 fc ff c6 05 5f 90 86 0c 01 48 8b 7c 24 40 e8 5a 04 00 00 48 c7 c7 60 82 90 8a 48 8b 74 24 60 48 89 c2 e8 36 a9 c7 ff <0f> 0b e9 1c fe ff ff 48 8b 4c 24 38 80 e1 07 38 c1 0f 8c ca f7 ff
RSP: 0018:ffffc90004e0f8c0 EFLAGS: 00010246
RAX: 476693593f04eb00 RBX: 0000000000000000 RCX: 0000000000080000
RDX: ffffc9000e2f8000 RSI: 00000000000030f4 RDI: 00000000000030f5
RBP: ffff888024f800d8 R08: ffff8880b8f279db R09: 1ffff110171e4f3b
R10: dffffc0000000000 R11: ffffed10171e4f3c R12: ffffffff8a800540
R13: ffffc90004e0fa00 R14: dffffc0000000000 R15: 0000000000000002
FS: 00007f9ea09426c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c3ce363 CR3: 0000000027fdb000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
trace_event_printf+0xea/0x140 kernel/trace/trace_output.c:321
trace_raw_output_initcall_level+0x93/0xd0 include/trace/events/initcall.h:10
s_show+0x135/0x300 kernel/trace/trace.c:4694
seq_read_iter+0x8af/0xc50 fs/seq_file.c:272
seq_read+0x171/0x210 fs/seq_file.c:162
vfs_read+0x2db/0x960 fs/read_write.c:468
ksys_read+0x14d/0x260 fs/read_write.c:613
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f9e9f99de99
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:00007f9ea0942028 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f9e9fc25fa0 RCX: 00007f9e9f99de99
RDX: 0000000000001000 RSI: 0000200000000180 RDI: 0000000000000004
RBP: 00007f9e9fa33eaf R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9e9fc26038 R14: 00007f9e9fc25fa0 R15: 00007ffc2e5f8e38
</TASK>


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