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

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KMSAN: uninit-value in io_req_task_work_add_remote

=====================================================
BUG: KMSAN: uninit-value in io_req_local_work_add io_uring/io_uring.c:1193 [inline]
BUG: KMSAN: uninit-value in io_req_task_work_add_remote+0x592/0x5e0 io_uring/io_uring.c:1241
 io_req_local_work_add io_uring/io_uring.c:1193 [inline]
 io_req_task_work_add_remote+0x592/0x5e0 io_uring/io_uring.c:1241
 io_msg_remote_post io_uring/msg_ring.c:102 [inline]
 io_msg_data_remote io_uring/msg_ring.c:133 [inline]
 io_msg_ring_data io_uring/msg_ring.c:152 [inline]
 io_msg_ring+0x1c38/0x1ef0 io_uring/msg_ring.c:305
 io_issue_sqe+0x383/0x22c0 io_uring/io_uring.c:1711
 io_queue_sqe io_uring/io_uring.c:1925 [inline]
 io_submit_sqe io_uring/io_uring.c:2181 [inline]
 io_submit_sqes+0x1259/0x2f20 io_uring/io_uring.c:2296
 __do_sys_io_uring_enter io_uring/io_uring.c:3206 [inline]
 __se_sys_io_uring_enter+0x40c/0x3ca0 io_uring/io_uring.c:3143
 __x64_sys_io_uring_enter+0x11f/0x1a0 io_uring/io_uring.c:3143
 x64_sys_call+0x2d82/0x3c10 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+0x9d6/0xe70 mm/page_alloc.c:4719
 __alloc_pages_node_noprof include/linux/gfp.h:269 [inline]
 alloc_pages_node_noprof include/linux/gfp.h:296 [inline]
 alloc_slab_page mm/slub.c:2321 [inline]
 allocate_slab+0x203/0x1220 mm/slub.c:2484
 new_slab mm/slub.c:2537 [inline]
 ___slab_alloc+0x12ef/0x35e0 mm/slub.c:3723
 __kmem_cache_alloc_bulk mm/slub.c:4759 [inline]
 kmem_cache_alloc_bulk_noprof+0x486/0x1330 mm/slub.c:4831
 __io_alloc_req_refill+0x84/0x560 io_uring/io_uring.c:940
 io_alloc_req io_uring/io_uring.h:393 [inline]
 io_submit_sqes+0x171b/0x2f20 io_uring/io_uring.c:2285
 __do_sys_io_uring_enter io_uring/io_uring.c:3206 [inline]
 __se_sys_io_uring_enter+0x40c/0x3ca0 io_uring/io_uring.c:3143
 __x64_sys_io_uring_enter+0x11f/0x1a0 io_uring/io_uring.c:3143
 x64_sys_call+0x2d82/0x3c10 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: 5924 Comm: syz.0.16 Not tainted 6.10.0-syzkaller-12268-g7a3fad30fd8b-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
=====================================================


Tested on:

commit:         7a3fad30 Merge tag 'random-6.11-rc1-for-linus' of git:..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13a6fa19980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f26f43c6f7db5ad2
dashboard link: https://syzkaller.appspot.com/bug?extid=82609b8937a4458106ca
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=178ca779980000