linux-kernel - [syzbot] [fs?] [mm?] KCSAN: data-race in bprm_execve / copy

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Message-ID: <67dc67f0.050a0220.25ae54.001f.GAE@google.com>
Date: Thu, 20 Mar 2025 12:09:36 -0700
From: syzbot <syzbot+1c486d0b62032c82a968@...kaller.appspotmail.com>
To: brauner@...nel.org, jack@...e.cz, kees@...nel.org, 
	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org, 
	linux-mm@...ck.org, syzkaller-bugs@...glegroups.com, viro@...iv.linux.org.uk
Subject: [syzbot] [fs?] [mm?] KCSAN: data-race in bprm_execve / copy_fs (4)

Hello,

syzbot found the following issue on:

HEAD commit:    a7f2e10ecd8f Merge tag 'hwmon-fixes-for-v6.14-rc8/6.14' of..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=114fee98580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f33d372c4021745
dashboard link: https://syzkaller.appspot.com/bug?extid=1c486d0b62032c82a968
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/614aabc71b48/disk-a7f2e10e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d47dd90a010a/vmlinux-a7f2e10e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/418d8cf8782b/bzImage-a7f2e10e.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1c486d0b62032c82a968@...kaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in bprm_execve / copy_fs

write to 0xffff8881044f8250 of 4 bytes by task 13692 on cpu 0:
 bprm_execve+0x748/0x9c0 fs/exec.c:1884
 do_execveat_common+0x769/0x7e0 fs/exec.c:1966
 do_execveat fs/exec.c:2051 [inline]
 __do_sys_execveat fs/exec.c:2125 [inline]
 __se_sys_execveat fs/exec.c:2119 [inline]
 __x64_sys_execveat+0x75/0x90 fs/exec.c:2119
 x64_sys_call+0x291e/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:323
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881044f8250 of 4 bytes by task 13686 on cpu 1:
 copy_fs+0x95/0xf0 kernel/fork.c:1770
 copy_process+0xc91/0x1f50 kernel/fork.c:2394
 kernel_clone+0x167/0x5e0 kernel/fork.c:2815
 __do_sys_clone3 kernel/fork.c:3119 [inline]
 __se_sys_clone3+0x1c1/0x200 kernel/fork.c:3098
 __x64_sys_clone3+0x31/0x40 kernel/fork.c:3098
 x64_sys_call+0x2d56/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:436
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000001 -> 0x00000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 13686 Comm: syz.1.3826 Not tainted 6.14.0-rc7-syzkaller-00074-ga7f2e10ecd8f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
==================================================================


---
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