[syzbot] [io-uring?] KMSAN: uninit-value in io_req_cqe_overflow (2)

[syzbot] [io-uring?] KMSAN: uninit-value in io_req_cqe_overflow (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    a5131c3fdf26 Merge tag 'x86-shstk-2024-05-13' of git://git..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=156ebcf4980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=64e100d74625a6a5
dashboard link: https://syzkaller.appspot.com/bug?extid=97d8b31fbab9db1efe55
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=1124b5b8980000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=155aa55c980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/81edac548743/disk-a5131c3f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/42f67aa888e5/vmlinux-a5131c3f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2e5cf5b3704d/bzImage-a5131c3f.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+97d8b31fbab9db1efe55@syzkaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in io_req_cqe_overflow+0x193/0x1c0 io_uring/io_uring.c:810
 io_req_cqe_overflow+0x193/0x1c0 io_uring/io_uring.c:810
 __io_submit_flush_completions+0x7eb/0x1be0 io_uring/io_uring.c:1464
 io_submit_flush_completions io_uring/io_uring.h:148 [inline]
 io_submit_state_end io_uring/io_uring.c:2234 [inline]
 io_submit_sqes+0x2b30/0x2f10 io_uring/io_uring.c:2350
 __do_sys_io_uring_enter io_uring/io_uring.c:3246 [inline]
 __se_sys_io_uring_enter+0x40f/0x3c80 io_uring/io_uring.c:3183
 __x64_sys_io_uring_enter+0x11f/0x1a0 io_uring/io_uring.c:3183
 x64_sys_call+0x2c0/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:427
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was stored to memory at:
 io_req_set_res io_uring/io_uring.h:215 [inline]
 io_recv_finish+0xf10/0x1560 io_uring/net.c:861
 io_recv+0x12ec/0x1ea0 io_uring/net.c:1175
 io_issue_sqe+0x429/0x22c0 io_uring/io_uring.c:1751
 io_queue_sqe io_uring/io_uring.c:1965 [inline]
 io_submit_sqe io_uring/io_uring.c:2220 [inline]
 io_submit_sqes+0x1266/0x2f10 io_uring/io_uring.c:2335
 __do_sys_io_uring_enter io_uring/io_uring.c:3246 [inline]
 __se_sys_io_uring_enter+0x40f/0x3c80 io_uring/io_uring.c:3183
 __x64_sys_io_uring_enter+0x11f/0x1a0 io_uring/io_uring.c:3183
 x64_sys_call+0x2c0/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:427
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:3877 [inline]
 slab_alloc_node mm/slub.c:3918 [inline]
 __do_kmalloc_node mm/slub.c:4038 [inline]
 __kmalloc+0x6e4/0x1060 mm/slub.c:4052
 kmalloc include/linux/slab.h:632 [inline]
 io_alloc_async_data+0xc0/0x220 io_uring/io_uring.c:1662
 io_msg_alloc_async io_uring/net.c:166 [inline]
 io_recvmsg_prep_setup io_uring/net.c:725 [inline]
 io_recvmsg_prep+0xbe8/0x1a20 io_uring/net.c:806
 io_init_req io_uring/io_uring.c:2135 [inline]
 io_submit_sqe io_uring/io_uring.c:2182 [inline]
 io_submit_sqes+0x1135/0x2f10 io_uring/io_uring.c:2335
 __do_sys_io_uring_enter io_uring/io_uring.c:3246 [inline]
 __se_sys_io_uring_enter+0x40f/0x3c80 io_uring/io_uring.c:3183
 __x64_sys_io_uring_enter+0x11f/0x1a0 io_uring/io_uring.c:3183
 x64_sys_call+0x2c0/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:427
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 1 PID: 5042 Comm: syz-executor135 Not tainted 6.9.0-syzkaller-01768-ga5131c3fdf26 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
=====================================================


---
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Re: [syzbot] [io-uring?] KMSAN: uninit-value in io_req_cqe_overflow (2)

[Jens Axboe]

#syz dup: [syzbot] [io-uring?] KMSAN: uninit-value in io_issue_sqe

-- 
Jens Axboe