From: Martin KaFai Lau <martin.lau@linux.dev>
To: syzbot <syzbot+9b8be5e35747291236c8@syzkaller.appspotmail.com>
Cc: andrii@kernel.org, ast@kernel.org, bpf@vger.kernel.org,
daniel@iogearbox.net, haoluo@google.com,
john.fastabend@gmail.com, jolsa@kernel.org, kpsingh@kernel.org,
linux-kernel@vger.kernel.org, sdf@google.com, song@kernel.org,
syzkaller-bugs@googlegroups.com, yonghong.song@linux.dev
Subject: Re: [syzbot] [bpf?] KMSAN: uninit-value in strnchr
Date: Mon, 8 Apr 2024 22:30:21 -0700 [thread overview]
Message-ID: <7c5ccbda-a4ea-4585-bb28-e1ae967cf741@linux.dev> (raw)
In-Reply-To: <0000000000009e2ff406130de279@google.com>
On 3/7/24 12:30 AM, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 04b8076df253 Merge tag 'firewire-fixes-6.8-rc7' of git://g..
> git tree: upstream
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=10bb9306180000
> kernel config: https://syzkaller.appspot.com/x/.config?x=80c7a82a572c0de3
> dashboard link: https://syzkaller.appspot.com/bug?extid=9b8be5e35747291236c8
> compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11093316180000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15a53082180000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/a4610b1ff2a7/disk-04b8076d.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/991e9d902d39/vmlinux-04b8076d.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/a5b8e8e98121/bzImage-04b8076d.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+9b8be5e35747291236c8@syzkaller.appspotmail.com
>
> =====================================================
> BUG: KMSAN: uninit-value in strnchr+0x90/0xd0 lib/string.c:388
> strnchr+0x90/0xd0 lib/string.c:388
> bpf_bprintf_prepare+0x1c2/0x23b0 kernel/bpf/helpers.c:829
> ____bpf_trace_printk kernel/trace/bpf_trace.c:385 [inline]
> bpf_trace_printk+0xec/0x3e0 kernel/trace/bpf_trace.c:375
> ___bpf_prog_run+0x2180/0xdb80 kernel/bpf/core.c:1986
> __bpf_prog_run32+0xb2/0xe0 kernel/bpf/core.c:2225
This is the same as the dev_map_lookup_elem report when running in interpreter
mode. It loads a different program to call bpf_trace_printk instead.
0: (6a) *(u16 *)(r10 -8) = 628106613
1: (bf) r1 = r10
2: (07) r1 += -8
3: (b7) r2 = 5
4: (bf) r3 = r1
5: (85) call bpf_trace_printk#-315920
6: (b7) r0 = 0
7: (95) exit
#syz dup: [syzbot] [bpf?] [net?] KMSAN: uninit-value in dev_map_lookup_elem
next prev parent reply other threads:[~2024-04-09 5:30 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-07 8:30 [syzbot] [bpf?] KMSAN: uninit-value in strnchr syzbot
2024-04-09 5:30 ` Martin KaFai Lau [this message]
2024-04-09 11:37 ` Edward Adam Davis
2024-04-10 0:22 ` syzbot
2024-04-09 11:37 ` [PATCH] bpf: fix " Edward Adam Davis
2024-04-09 11:52 ` Edward Adam Davis
2024-04-09 17:59 ` Martin KaFai Lau
2024-04-10 0:28 ` Edward Adam Davis
2024-04-11 12:13 ` Edward Adam Davis
2024-04-09 13:13 ` [syzbot] [bpf?] KMSAN: " Edward Adam Davis
2024-04-10 2:32 ` syzbot
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