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

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

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    99d99825fc07 Merge tag 'nfs-for-6.6-1' of git://git.linux-..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=10c292a8680000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e9fadcd263e8d242
dashboard link: https://syzkaller.appspot.com/bug?extid=8d9c06e026c513a69f2f
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=1358d7dfa80000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=14c99d9fa80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/7e9fa7fad7d0/disk-99d99825.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/424ca21fc443/vmlinux-99d99825.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d4de08b26e5b/bzImage-99d99825.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8d9c06e026c513a69f2f@syzkaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in io_fixup_rw_res io_uring/rw.c:273 [inline]
BUG: KMSAN: uninit-value in io_rw_fail+0x1a7/0x1b0 io_uring/rw.c:996
 io_fixup_rw_res io_uring/rw.c:273 [inline]
 io_rw_fail+0x1a7/0x1b0 io_uring/rw.c:996
 io_req_defer_failed+0x217/0x3e0 io_uring/io_uring.c:1030
 io_queue_sqe_fallback+0x1f4/0x260 io_uring/io_uring.c:2063
 io_submit_state_end io_uring/io_uring.c:2308 [inline]
 io_submit_sqes+0x2b83/0x2ff0 io_uring/io_uring.c:2426
 __do_sys_io_uring_enter io_uring/io_uring.c:3620 [inline]
 __se_sys_io_uring_enter+0x491/0x43f0 io_uring/io_uring.c:3554
 __x64_sys_io_uring_enter+0x11b/0x1a0 io_uring/io_uring.c:3554
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Uninit was created at:
 slab_post_alloc_hook+0x12f/0xb70 mm/slab.h:767
 slab_alloc_node mm/slub.c:3478 [inline]
 __kmem_cache_alloc_node+0x536/0x8d0 mm/slub.c:3517
 __do_kmalloc_node mm/slab_common.c:1022 [inline]
 __kmalloc+0x121/0x3c0 mm/slab_common.c:1036
 kmalloc include/linux/slab.h:603 [inline]
 io_alloc_async_data io_uring/io_uring.c:1745 [inline]
 io_req_prep_async+0x384/0x5a0 io_uring/io_uring.c:1766
 io_queue_sqe_fallback+0x95/0x260 io_uring/io_uring.c:2060
 io_submit_state_end io_uring/io_uring.c:2308 [inline]
 io_submit_sqes+0x2b83/0x2ff0 io_uring/io_uring.c:2426
 __do_sys_io_uring_enter io_uring/io_uring.c:3620 [inline]
 __se_sys_io_uring_enter+0x491/0x43f0 io_uring/io_uring.c:3554
 __x64_sys_io_uring_enter+0x11b/0x1a0 io_uring/io_uring.c:3554
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

CPU: 0 PID: 4988 Comm: syz-executor352 Not tainted 6.5.0-syzkaller-09276-g99d99825fc07 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
=====================================================


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

[Jens Axboe]

#syz fix: io_uring/rw: ensure io->bytes_done is always initialized

-- 
Jens Axboe