[syzbot] KMSAN: uninit-value in io_req_cqe_overflow

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: ac3859c02d7f block: kmsan: skip bio block merging logic fo..
git tree: https://github.com/google/kmsan.git master
console+strace: https://syzkaller.appspot.com/x/log.txt?x=1394e48b080000
kernel config: https://syzkaller.appspot.com/x/.config?x=8e64bc5364a1307e
dashboard link: https://syzkaller.appspot.com/bug?extid=12dde80bf174ac8ae285
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project.git 610139d2d9ce6746b3c617fb3e2f7886272d26ff), GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12cb6983080000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17744fbd080000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+12dde8...@syzkaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in io_req_cqe_overflow+0x1f8/0x220 io_uring/io_uring.c:687
io_req_cqe_overflow+0x1f8/0x220 io_uring/io_uring.c:687
__io_fill_cqe_req+0x4ad/0x830 io_uring/io_uring.h:121
__io_submit_flush_completions io_uring/io_uring.c:1192 [inline]
io_submit_flush_completions+0x11c/0x390 io_uring/io_uring.c:166
io_submit_state_end io_uring/io_uring.c:2025 [inline]
io_submit_sqes+0x7d3/0xd50 io_uring/io_uring.c:2137
__do_sys_io_uring_enter io_uring/io_uring.c:3053 [inline]
__se_sys_io_uring_enter+0x597/0x1d30 io_uring/io_uring.c:2983
__x64_sys_io_uring_enter+0x117/0x190 io_uring/io_uring.c:2983
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

Uninit was stored to memory at:
io_req_set_res io_uring/io_uring.h:156 [inline]
io_recv_finish io_uring/net.c:537 [inline]
io_recv+0x18ee/0x1d00 io_uring/net.c:845
io_issue_sqe+0x3b1/0x11d0 io_uring/io_uring.c:1576
io_queue_sqe io_uring/io_uring.c:1753 [inline]
io_submit_sqe+0xb40/0x1be0 io_uring/io_uring.c:2011
io_submit_sqes+0x542/0xd50 io_uring/io_uring.c:2122
__do_sys_io_uring_enter io_uring/io_uring.c:3053 [inline]
__se_sys_io_uring_enter+0x597/0x1d30 io_uring/io_uring.c:2983
__x64_sys_io_uring_enter+0x117/0x190 io_uring/io_uring.c:2983
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

Local variable msg created at:
io_recv+0x4b/0x1d00 io_uring/net.c:763
io_issue_sqe+0x3b1/0x11d0 io_uring/io_uring.c:1576

CPU: 0 PID: 3487 Comm: syz-executor126 Not tainted 6.0.0-rc2-syzkaller-47461-gac3859c02d7f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
=====================================================


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[syzbot]

Auto-closing this bug as obsolete.
No recent activity, existing reproducers are no longer triggering the issue.