[syzbot] [io-uring?] KMSAN: uninit-value in io_nop

[syzbot <syzbot+9a8500a45c2cabdf9577@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    43fb83c17ba2 Merge tag 'soc-arm-6.13' of git://git.kernel...
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=134feb78580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=9f17942989df952c
dashboard link: https://syzkaller.appspot.com/bug?extid=9a8500a45c2cabdf9577
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=16f767f7980000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12f50ec0580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/e1e82262b7ac/disk-43fb83c1.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/7ca6e1c46dc5/vmlinux-43fb83c1.xz
kernel image: https://storage.googleapis.com/syzbot-assets/63aaea837532/bzImage-43fb83c1.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+9a8500a45c2cabdf9577@syzkaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in io_nop+0x549/0x8a0 io_uring/nop.c:55
 io_nop+0x549/0x8a0 io_uring/nop.c:55
 io_issue_sqe+0x420/0x2130 io_uring/io_uring.c:1712
 io_queue_sqe io_uring/io_uring.c:1922 [inline]
 io_submit_sqe io_uring/io_uring.c:2177 [inline]
 io_submit_sqes+0x11bc/0x2f80 io_uring/io_uring.c:2294
 __do_sys_io_uring_enter io_uring/io_uring.c:3365 [inline]
 __se_sys_io_uring_enter+0x423/0x4aa0 io_uring/io_uring.c:3300
 __x64_sys_io_uring_enter+0x11f/0x1a0 io_uring/io_uring.c:3300
 x64_sys_call+0xce5/0x3c30 arch/x86/include/generated/asm/syscalls_64.h:427
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at:
 __alloc_pages_noprof+0x9a7/0xe00 mm/page_alloc.c:4774
 alloc_pages_mpol_noprof+0x299/0x990 mm/mempolicy.c:2265
 alloc_pages_noprof+0x1bf/0x1e0 mm/mempolicy.c:2345
 alloc_slab_page mm/slub.c:2412 [inline]
 allocate_slab+0x320/0x12e0 mm/slub.c:2578
 new_slab mm/slub.c:2631 [inline]
 ___slab_alloc+0x12ef/0x35e0 mm/slub.c:3818
 __kmem_cache_alloc_bulk mm/slub.c:4895 [inline]
 kmem_cache_alloc_bulk_noprof+0x486/0x1330 mm/slub.c:4967
 __io_alloc_req_refill+0x84/0x5b0 io_uring/io_uring.c:958
 io_alloc_req io_uring/io_uring.h:411 [inline]
 io_submit_sqes+0x9a2/0x2f80 io_uring/io_uring.c:2283
 __do_sys_io_uring_enter io_uring/io_uring.c:3365 [inline]
 __se_sys_io_uring_enter+0x423/0x4aa0 io_uring/io_uring.c:3300
 __x64_sys_io_uring_enter+0x11f/0x1a0 io_uring/io_uring.c:3300
 x64_sys_call+0xce5/0x3c30 arch/x86/include/generated/asm/syscalls_64.h:427
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 0 UID: 0 PID: 5798 Comm: syz-executor426 Not tainted 6.12.0-syzkaller-03657-g43fb83c17ba2 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
=====================================================


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup