Re: [syzbot] [hams?] KMSAN: uninit-value in nr_route_frame

[syzbot <syzbot+f770ce3566e60e5573ac@syzkaller.appspotmail.com>]

Hello,

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

=====================================================
BUG: KMSAN: uninit-value in nr_route_frame+0x4a9/0xfc0 net/netrom/nr_route.c:787
 nr_route_frame+0x4a9/0xfc0 net/netrom/nr_route.c:787
 nr_xmit+0x5a/0x1c0 net/netrom/nr_dev.c:144
 __netdev_start_xmit include/linux/netdevice.h:4980 [inline]
 netdev_start_xmit include/linux/netdevice.h:4994 [inline]
 xmit_one net/core/dev.c:3547 [inline]
 dev_hard_start_xmit+0x244/0xa10 net/core/dev.c:3563
 __dev_queue_xmit+0x33ed/0x51c0 net/core/dev.c:4351
 dev_queue_xmit include/linux/netdevice.h:3171 [inline]
 raw_sendmsg+0x64e/0xc10 net/ieee802154/socket.c:299
 ieee802154_sock_sendmsg+0x91/0xc0 net/ieee802154/socket.c:96
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 ____sys_sendmsg+0x9c2/0xd60 net/socket.c:2584
 ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2638
 __sys_sendmsg net/socket.c:2667 [inline]
 __do_sys_sendmsg net/socket.c:2676 [inline]
 __se_sys_sendmsg net/socket.c:2674 [inline]
 __x64_sys_sendmsg+0x307/0x490 net/socket.c:2674
 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+0x63/0x6b

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:3819 [inline]
 slab_alloc_node mm/slub.c:3860 [inline]
 kmem_cache_alloc_node+0x5cb/0xbc0 mm/slub.c:3903
 kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:560
 __alloc_skb+0x33d/0x7a0 net/core/skbuff.c:651
 alloc_skb include/linux/skbuff.h:1296 [inline]
 alloc_skb_with_frags+0xc8/0xbd0 net/core/skbuff.c:6395
 sock_alloc_send_pskb+0xa80/0xbf0 net/core/sock.c:2783
 sock_alloc_send_skb include/net/sock.h:1855 [inline]
 raw_sendmsg+0x367/0xc10 net/ieee802154/socket.c:282
 ieee802154_sock_sendmsg+0x91/0xc0 net/ieee802154/socket.c:96
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 ____sys_sendmsg+0x9c2/0xd60 net/socket.c:2584
 ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2638
 __sys_sendmsg net/socket.c:2667 [inline]
 __do_sys_sendmsg net/socket.c:2676 [inline]
 __se_sys_sendmsg net/socket.c:2674 [inline]
 __x64_sys_sendmsg+0x307/0x490 net/socket.c:2674
 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+0x63/0x6b

CPU: 1 PID: 5501 Comm: syz-executor.0 Not tainted 6.8.0-rc6-syzkaller-g04b8076df253-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
=====================================================


Tested on:

commit:         04b8076d Merge tag 'firewire-fixes-6.8-rc7' of git://g..
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=149cd06c180000
kernel config:  https://syzkaller.appspot.com/x/.config?x=80c7a82a572c0de3
dashboard link: https://syzkaller.appspot.com/bug?extid=f770ce3566e60e5573ac
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1666dc36180000