[moderation] [io-uring?] KCSAN: data-race in io_submit_sqes / prepare_creds

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 0f61b1860cc3 Linux 6.19-rc5
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=118e8052580000
kernel config: https://syzkaller.appspot.com/x/.config?x=c160236e1ef1e401
dashboard link: https://syzkaller.appspot.com/bug?extid=28bf9d76d89a9ce80187
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
CC: [ax...@kernel.dk io-u...@vger.kernel.org linux-...@vger.kernel.org]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/352f0edfdcea/disk-0f61b186.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/21694b81d992/vmlinux-0f61b186.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2c987d798e03/bzImage-0f61b186.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+28bf9d...@syzkaller.appspotmail.com

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

write to 0xffff8881031a6b28 of 4 bytes by task 12447 on cpu 1:
get_cred_many include/linux/cred.h:219 [inline]
get_cred include/linux/cred.h:235 [inline]
io_init_req io_uring/io_uring.c:2226 [inline]
io_submit_sqe io_uring/io_uring.c:2282 [inline]
io_submit_sqes+0x68b/0x11b0 io_uring/io_uring.c:2435
__do_sys_io_uring_enter io_uring/io_uring.c:3285 [inline]
__se_sys_io_uring_enter+0x1bd/0x1a30 io_uring/io_uring.c:3224
__x64_sys_io_uring_enter+0x78/0x90 io_uring/io_uring.c:3224
x64_sys_call+0x27e4/0x3000 arch/x86/include/generated/asm/syscalls_64.h:427
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xca/0x2b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881031a6a80 of 184 bytes by task 12448 on cpu 0:
prepare_creds+0x6e/0x550 kernel/cred.c:192
copy_creds+0x8f/0x340 kernel/cred.c:286
copy_process+0x638/0x1ef0 kernel/fork.c:2086
kernel_clone+0x16c/0x5c0 kernel/fork.c:2651
__do_sys_clone kernel/fork.c:2792 [inline]
__se_sys_clone kernel/fork.c:2776 [inline]
__x64_sys_clone+0xe6/0x120 kernel/fork.c:2776
x64_sys_call+0x12d0/0x3000 arch/x86/include/generated/asm/syscalls_64.h:57
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xca/0x2b0 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: 12448 Comm: syz.4.2930 Not tainted syzkaller #0 PREEMPT(voluntary)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
==================================================================


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