Subject: [syzbot] [net?] KMSAN: uninit-value in geneve_xmit (3)

From: syzbot <[email-masked]>
Date: Wed, 03 Apr 2024 04:35:32 -0700

Hello,

syzbot found the following issue on:

HEAD commit:    928a87efa423 Merge tag 'gfs2-v6.8-fix' of git://git.kernel..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=10c17b4e180000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e2599baf258ef795
dashboard link: https://syzkaller.appspot.com/bug?extid=9ee20ec1de7b3168db09
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=16cd6479180000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=16cec009180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/7d66fa7ed5c7/disk-928a87ef.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/8b511d64cde0/vmlinux-928a87ef.xz
kernel image: https://storage.googleapis.com/syzbot-assets/8810588440a2/bzImage-928a87ef.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email-masked]

=====================================================
BUG: KMSAN: uninit-value in geneve_xmit_skb drivers/net/geneve.c:910 [inline]
BUG: KMSAN: uninit-value in geneve_xmit+0x302d/0x5420 drivers/net/geneve.c:1030
 geneve_xmit_skb drivers/net/geneve.c:910 [inline]
 geneve_xmit+0x302d/0x5420 drivers/net/geneve.c:1030
 __netdev_start_xmit include/linux/netdevice.h:4903 [inline]
 netdev_start_xmit include/linux/netdevice.h:4917 [inline]
 xmit_one net/core/dev.c:3531 [inline]
 dev_hard_start_xmit+0x247/0xa20 net/core/dev.c:3547
 __dev_queue_xmit+0x348d/0x52c0 net/core/dev.c:4335
 dev_queue_xmit include/linux/netdevice.h:3091 [inline]
 packet_xmit+0x9c/0x6c0 net/packet/af_packet.c:276
 packet_snd net/packet/af_packet.c:3081 [inline]
 packet_sendmsg+0x8bb0/0x9ef0 net/packet/af_packet.c:3113
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg+0x30f/0x380 net/socket.c:745
 __sys_sendto+0x685/0x830 net/socket.c:2191
 __do_sys_sendto net/socket.c:2203 [inline]
 __se_sys_sendto net/socket.c:2199 [inline]
 __x64_sys_sendto+0x125/0x1d0 net/socket.c:2199
 do_syscall_64+0xd5/0x1f0
 entry_SYSCALL_64_after_hwframe+0x6d/0x75

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:3804 [inline]
 slab_alloc_node mm/slub.c:3845 [inline]
 kmem_cache_alloc_node+0x613/0xc50 mm/slub.c:3888
 kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:577
 __alloc_skb+0x35b/0x7a0 net/core/skbuff.c:668
 alloc_skb include/linux/skbuff.h:1318 [inline]
 alloc_skb_with_frags+0xc8/0xbf0 net/core/skbuff.c:6504
 sock_alloc_send_pskb+0xa81/0xbf0 net/core/sock.c:2795
 packet_alloc_skb net/packet/af_packet.c:2930 [inline]
 packet_snd net/packet/af_packet.c:3024 [inline]
 packet_sendmsg+0x722d/0x9ef0 net/packet/af_packet.c:3113
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg+0x30f/0x380 net/socket.c:745
 __sys_sendto+0x685/0x830 net/socket.c:2191
 __do_sys_sendto net/socket.c:2203 [inline]
 __se_sys_sendto net/socket.c:2199 [inline]
 __x64_sys_sendto+0x125/0x1d0 net/socket.c:2199
 do_syscall_64+0xd5/0x1f0
 entry_SYSCALL_64_after_hwframe+0x6d/0x75

CPU: 0 PID: 5033 Comm: syz-executor346 Not tainted 6.9.0-rc1-syzkaller-00005-g928a87efa423 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
=====================================================

---
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