[moderation] [fs?] KCSAN: data-race in init_file / prepare_creds (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 302f88ff3584 Merge tag 'for-linus' of git://git.kernel.org..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12ff4782580000
kernel config: https://syzkaller.appspot.com/x/.config?x=c0dd0a92e88efc24
dashboard link: https://syzkaller.appspot.com/bug?extid=0873b15fae924aab48d4
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
CC: [bra...@kernel.org ja...@suse.cz linux-...@vger.kernel.org linux-...@vger.kernel.org vi...@zeniv.linux.org.uk]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c645ea28adbb/disk-302f88ff.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6eb2ef992193/vmlinux-302f88ff.xz
kernel image: https://storage.googleapis.com/syzbot-assets/1a9bae01cf09/bzImage-302f88ff.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+0873b1...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in init_file / prepare_creds

write to 0xffff88810da31528 of 4 bytes by task 11425 on cpu 1:
get_cred_many include/linux/cred.h:202 [inline]
get_cred include/linux/cred.h:218 [inline]
init_file+0x2e/0x1d0 fs/file_table.c:155
alloc_empty_file+0x8b/0x200 fs/file_table.c:238
alloc_file fs/file_table.c:351 [inline]
alloc_file_pseudo+0xc6/0x160 fs/file_table.c:380
sock_alloc_file+0x9c/0x1e0 net/socket.c:470
sock_map_fd net/socket.c:500 [inline]
__sys_socket+0x116/0x180 net/socket.c:1692
__do_sys_socket net/socket.c:1697 [inline]
__se_sys_socket net/socket.c:1695 [inline]
__x64_sys_socket+0x3f/0x50 net/socket.c:1695
x64_sys_call+0x285a/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:42
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88810da31480 of 184 bytes by task 11424 on cpu 0:
prepare_creds+0x6c/0x4c0 kernel/cred.c:219
copy_creds+0x8f/0x3f0 kernel/cred.c:312
copy_process+0x658/0x1f90 kernel/fork.c:2033
kernel_clone+0x16c/0x5b0 kernel/fork.c:2599
__do_sys_clone kernel/fork.c:2742 [inline]
__se_sys_clone kernel/fork.c:2726 [inline]
__x64_sys_clone+0xe6/0x120 kernel/fork.c:2726
x64_sys_call+0x2c59/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:57
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 11424 Comm: syz.1.12764 Not tainted 6.16.0-rc7-syzkaller-00127-g302f88ff3584 #0 PREEMPT(voluntary)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
==================================================================


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