linux-kernel - [syzbot] [bpf?] KMSAN: uninit-value in __bpf

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Message-ID: <00000000000011b2f00614076749@google.com>
Date: Tue, 19 Mar 2024 11:11:26 -0700
From: syzbot <syzbot+8ac8b7b2292ea867a162@...kaller.appspotmail.com>
To: andrii@...nel.org, ast@...nel.org, bpf@...r.kernel.org, 
	daniel@...earbox.net, eddyz87@...il.com, haoluo@...gle.com, 
	john.fastabend@...il.com, jolsa@...nel.org, kpsingh@...nel.org, 
	linux-kernel@...r.kernel.org, martin.lau@...ux.dev, sdf@...gle.com, 
	song@...nel.org, syzkaller-bugs@...glegroups.com, yonghong.song@...ux.dev
Subject: [syzbot] [bpf?] KMSAN: uninit-value in __bpf_strtoull

Hello,

syzbot found the following issue on:

HEAD commit:    741e9d668aa5 Merge tag 'scsi-misc' of git://git.kernel.org..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=113721f1180000
kernel config:  https://syzkaller.appspot.com/x/.config?x=48bb382b96e7eda7
dashboard link: https://syzkaller.appspot.com/bug?extid=8ac8b7b2292ea867a162
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: i386

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/7e1776e6e382/disk-741e9d66.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/69580881d554/vmlinux-741e9d66.xz
kernel image: https://storage.googleapis.com/syzbot-assets/65e4047a1117/bzImage-741e9d66.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8ac8b7b2292ea867a162@...kaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in __bpf_strtoull+0x245/0x5b0 kernel/bpf/helpers.c:465
 __bpf_strtoull+0x245/0x5b0 kernel/bpf/helpers.c:465
 __bpf_strtoll kernel/bpf/helpers.c:504 [inline]
 ____bpf_strtol kernel/bpf/helpers.c:525 [inline]
 bpf_strtol+0x7c/0x270 kernel/bpf/helpers.c:519
 ___bpf_prog_run+0x13fe/0xe0f0 kernel/bpf/core.c:1997
 __bpf_prog_run96+0xb5/0xe0 kernel/bpf/core.c:2236
 bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline]
 __bpf_prog_run include/linux/filter.h:657 [inline]
 bpf_prog_run_xdp include/net/xdp.h:514 [inline]
 bpf_test_run+0x43e/0xc30 net/bpf/test_run.c:423
 bpf_prog_test_run_xdp+0xeaa/0x1a40 net/bpf/test_run.c:1269
 bpf_prog_test_run+0x6b7/0xad0 kernel/bpf/syscall.c:4240
 __sys_bpf+0x6aa/0xd90 kernel/bpf/syscall.c:5649
 __do_sys_bpf kernel/bpf/syscall.c:5738 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5736 [inline]
 __ia32_sys_bpf+0xa0/0xe0 kernel/bpf/syscall.c:5736
 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
 __do_fast_syscall_32+0xba/0x120 arch/x86/entry/common.c:321
 do_fast_syscall_32+0x38/0x80 arch/x86/entry/common.c:346
 do_SYSENTER_32+0x1f/0x30 arch/x86/entry/common.c:384
 entry_SYSENTER_compat_after_hwframe+0x7a/0x84

Local variable stack created at:
 __bpf_prog_run96+0x45/0xe0 kernel/bpf/core.c:2236
 bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline]
 __bpf_prog_run include/linux/filter.h:657 [inline]
 bpf_prog_run_xdp include/net/xdp.h:514 [inline]
 bpf_test_run+0x43e/0xc30 net/bpf/test_run.c:423

CPU: 0 PID: 11097 Comm: syz-executor.0 Not tainted 6.8.0-syzkaller-11339-g741e9d668aa5 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
=====================================================


---
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