From: syzbot <syzbot+ba80855313e6fa65717a@syzkaller.appspotmail.com>
To: andrii@kernel.org, ast@kernel.org, bpf@vger.kernel.org,
daniel@iogearbox.net, eddyz87@gmail.com, haoluo@google.com,
john.fastabend@gmail.com, jolsa@kernel.org, kpsingh@kernel.org,
linux-kernel@vger.kernel.org, martin.lau@linux.dev,
sdf@fomichev.me, song@kernel.org,
syzkaller-bugs@googlegroups.com, yonghong.song@linux.dev
Subject: Re: [syzbot] [bpf?] KMSAN: uninit-value in handle_bug
Date: Mon, 16 Mar 2026 23:45:27 -0700 [thread overview]
Message-ID: <69b8f887.050a0220.248e02.0127.GAE@google.com> (raw)
In-Reply-To: <69343e08.a70a0220.38f243.002c.GAE@google.com>
syzbot has found a reproducer for the following issue on:
HEAD commit: 2d1373e4246d Merge tag 'for-7.0-rc4-tag' of git://git.kern..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=146bc4da580000
kernel config: https://syzkaller.appspot.com/x/.config?x=963de479f54c6dbb
dashboard link: https://syzkaller.appspot.com/bug?extid=ba80855313e6fa65717a
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14b4a8da580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16773406580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/bef78207d3f7/disk-2d1373e4.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/35fd28ca5034/vmlinux-2d1373e4.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c2b759faae9e/bzImage-2d1373e4.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ba80855313e6fa65717a@syzkaller.appspotmail.com
------------[ cut here ]------------
=====================================================
BUG: KMSAN: uninit-value in vsnprintf+0x15be/0x1b00 lib/vsprintf.c:2912
vsnprintf+0x15be/0x1b00 lib/vsprintf.c:2912
vprintk_store+0x350/0x1550 kernel/printk/printk.c:2307
vprintk_emit+0x2c8/0xba0 kernel/printk/printk.c:2455
vprintk_default+0x3f/0x50 kernel/printk/printk.c:2494
vprintk+0x36/0x50 kernel/printk/printk_safe.c:82
__warn_printf lib/bug.c:190 [inline]
__report_bug+0xa10/0xe00 lib/bug.c:244
report_bug_entry+0x17c/0x220 lib/bug.c:269
handle_bug+0xe5/0x230 arch/x86/kernel/traps.c:430
exc_invalid_op+0x1f/0x50 arch/x86/kernel/traps.c:489
asm_exc_invalid_op+0x1f/0x30 arch/x86/include/asm/idtentry.h:616
reg_bounds_sanity_check+0x571/0x14e0 kernel/bpf/verifier.c:2817
reg_set_min_max+0x34b/0x450 kernel/bpf/verifier.c:17159
check_cond_jmp_op+0x3bf5/0x5370 kernel/bpf/verifier.c:17609
do_check_insn kernel/bpf/verifier.c:21168 [inline]
do_check+0xc7e8/0x1add0 kernel/bpf/verifier.c:21308
do_check_common+0x2705/0x4270 kernel/bpf/verifier.c:24650
do_check_main kernel/bpf/verifier.c:24733 [inline]
bpf_check+0x1f159/0x27e90 kernel/bpf/verifier.c:26056
bpf_prog_load+0x2b41/0x3140 kernel/bpf/syscall.c:3089
__sys_bpf+0x8e0/0xee0 kernel/bpf/syscall.c:6228
__do_sys_bpf kernel/bpf/syscall.c:6341 [inline]
__se_sys_bpf kernel/bpf/syscall.c:6339 [inline]
__x64_sys_bpf+0xa4/0xf0 kernel/bpf/syscall.c:6339
x64_sys_call+0x13d0/0x3ea0 arch/x86/include/generated/asm/syscalls_64.h:322
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x134/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Uninit was stored to memory at:
vsnprintf+0x15b7/0x1b00 lib/vsprintf.c:-1
vprintk_store+0x350/0x1550 kernel/printk/printk.c:2307
vprintk_emit+0x2c8/0xba0 kernel/printk/printk.c:2455
vprintk_default+0x3f/0x50 kernel/printk/printk.c:2494
vprintk+0x36/0x50 kernel/printk/printk_safe.c:82
__warn_printf lib/bug.c:190 [inline]
__report_bug+0xa10/0xe00 lib/bug.c:244
report_bug_entry+0x17c/0x220 lib/bug.c:269
handle_bug+0xe5/0x230 arch/x86/kernel/traps.c:430
exc_invalid_op+0x1f/0x50 arch/x86/kernel/traps.c:489
asm_exc_invalid_op+0x1f/0x30 arch/x86/include/asm/idtentry.h:616
Local variable pflags created at:
try_charge_memcg+0x63/0x1c20 mm/memcontrol.c:2367
obj_cgroup_charge_pages+0x69/0x330 mm/memcontrol.c:2857
CPU: 1 UID: 0 PID: 5997 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
=====================================================
---
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:[~2026-03-17 6:45 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-06 14:30 [syzbot] [bpf?] KMSAN: uninit-value in handle_bug syzbot
2026-03-17 6:45 ` syzbot [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=69b8f887.050a0220.248e02.0127.GAE@google.com \
--to=syzbot+ba80855313e6fa65717a@syzkaller.appspotmail.com \
--cc=andrii@kernel.org \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=eddyz87@gmail.com \
--cc=haoluo@google.com \
--cc=john.fastabend@gmail.com \
--cc=jolsa@kernel.org \
--cc=kpsingh@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=martin.lau@linux.dev \
--cc=sdf@fomichev.me \
--cc=song@kernel.org \
--cc=syzkaller-bugs@googlegroups.com \
--cc=yonghong.song@linux.dev \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox