[syzbot] [openvswitch?] KMSAN: uninit-value in validate_set (2)

[syzbot <syzbot+b07a9da40df1576b8048@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    0af2f6be1b42 Linux 6.15-rc1
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=14e26d78580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=7cfe1169d7fc8523
dashboard link: https://syzkaller.appspot.com/bug?extid=b07a9da40df1576b8048
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=1367bb4c580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1495d23f980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/7526e189e315/disk-0af2f6be.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/60a25cc98e41/vmlinux-0af2f6be.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2d7bf8af0faf/bzImage-0af2f6be.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b07a9da40df1576b8048@syzkaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in validate_set+0x1a2/0x1640 net/openvswitch/flow_netlink.c:2879
 validate_set+0x1a2/0x1640 net/openvswitch/flow_netlink.c:2879
 __ovs_nla_copy_actions+0x2efc/0x61a0 net/openvswitch/flow_netlink.c:3383
 ovs_nla_copy_actions+0x36b/0x550 net/openvswitch/flow_netlink.c:3543
 get_flow_actions+0x99/0x1d0 net/openvswitch/datapath.c:1148
 ovs_nla_init_match_and_action+0x221/0x420 net/openvswitch/datapath.c:1198
 ovs_flow_cmd_set+0x320/0xec0 net/openvswitch/datapath.c:1236
 genl_family_rcv_msg_doit net/netlink/genetlink.c:1115 [inline]
 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
 genl_rcv_msg+0x1214/0x12c0 net/netlink/genetlink.c:1210
 netlink_rcv_skb+0x375/0x650 net/netlink/af_netlink.c:2534
 genl_rcv+0x40/0x60 net/netlink/genetlink.c:1219
 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
 netlink_unicast+0xf52/0x1260 net/netlink/af_netlink.c:1339
 netlink_sendmsg+0x10da/0x11e0 net/netlink/af_netlink.c:1883
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x30f/0x380 net/socket.c:727
 ____sys_sendmsg+0x890/0xda0 net/socket.c:2566
 ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2620
 __sys_sendmsg net/socket.c:2652 [inline]
 __do_sys_sendmsg net/socket.c:2657 [inline]
 __se_sys_sendmsg net/socket.c:2655 [inline]
 __x64_sys_sendmsg+0x212/0x3c0 net/socket.c:2655
 x64_sys_call+0x2e0f/0x3c80 arch/x86/include/generated/asm/syscalls_64.h:47
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x1e0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:4157 [inline]
 slab_alloc_node mm/slub.c:4200 [inline]
 kmem_cache_alloc_node_noprof+0x921/0xe10 mm/slub.c:4252
 kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:577
 __alloc_skb+0x366/0x7b0 net/core/skbuff.c:668
 alloc_skb include/linux/skbuff.h:1340 [inline]
 netlink_alloc_large_skb+0x1b4/0x280 net/netlink/af_netlink.c:1187
 netlink_sendmsg+0xa96/0x11e0 net/netlink/af_netlink.c:1858
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x30f/0x380 net/socket.c:727
 ____sys_sendmsg+0x890/0xda0 net/socket.c:2566
 ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2620
 __sys_sendmsg net/socket.c:2652 [inline]
 __do_sys_sendmsg net/socket.c:2657 [inline]
 __se_sys_sendmsg net/socket.c:2655 [inline]
 __x64_sys_sendmsg+0x212/0x3c0 net/socket.c:2655
 x64_sys_call+0x2e0f/0x3c80 arch/x86/include/generated/asm/syscalls_64.h:47
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x1e0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 1 UID: 0 PID: 5787 Comm: syz-executor365 Not tainted 6.15.0-rc1-syzkaller #0 PREEMPT(undef) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
=====================================================


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