[syzbot] [crypto?] KMSAN: uninit-value in af_alg_free_sg (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    0dd3ee311255 Linux 6.7
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=169326ade80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=373206b1ae2fe3d4
dashboard link: https://syzkaller.appspot.com/bug?extid=3266db0c26d1fbbe3abb
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/983c6822f4f0/disk-0dd3ee31.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f7ac98ec5a78/vmlinux-0dd3ee31.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f568a85da78f/bzImage-0dd3ee31.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3266db0c26d1fbbe3abb@xxxxxxxxxxxxxxxxxxxxxxxxx

=====================================================
BUG: KMSAN: uninit-value in af_alg_free_sg+0x1a7/0x270 crypto/af_alg.c:547
 af_alg_free_sg+0x1a7/0x270 crypto/af_alg.c:547
 hash_sendmsg+0x1938/0x1c30 crypto/algif_hash.c:172
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 ____sys_sendmsg+0x9c2/0xd60 net/socket.c:2586
 ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2640
 __sys_sendmmsg+0x3c4/0x950 net/socket.c:2726
 __do_sys_sendmmsg net/socket.c:2755 [inline]
 __se_sys_sendmmsg net/socket.c:2752 [inline]
 __x64_sys_sendmmsg+0xbc/0x120 net/socket.c:2752
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

Uninit was created at:
 slab_post_alloc_hook+0x129/0xa70 mm/slab.h:768
 slab_alloc_node mm/slub.c:3478 [inline]
 __kmem_cache_alloc_node+0x5c9/0x970 mm/slub.c:3517
 __do_kmalloc_node mm/slab_common.c:1006 [inline]
 __kmalloc+0x121/0x3c0 mm/slab_common.c:1020
 kmalloc include/linux/slab.h:604 [inline]
 sock_kmalloc+0x128/0x1c0 net/core/sock.c:2688
 hash_accept_parent_nokey crypto/algif_hash.c:418 [inline]
 hash_accept_parent+0xbf/0x430 crypto/algif_hash.c:445
 af_alg_accept+0x1fc/0x810 crypto/af_alg.c:439
 hash_accept+0x340/0x790 crypto/algif_hash.c:254
 do_accept+0x606/0xa80 net/socket.c:1929
 __sys_accept4_file net/socket.c:1969 [inline]
 __sys_accept4+0x18e/0x360 net/socket.c:1999
 __do_sys_accept4 net/socket.c:2010 [inline]
 __se_sys_accept4 net/socket.c:2007 [inline]
 __x64_sys_accept4+0xb8/0x120 net/socket.c:2007
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

CPU: 1 PID: 6735 Comm: syz-executor.4 Not tainted 6.7.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
=====================================================


---
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@xxxxxxxxxxxxxxxx.

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 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