syzbot has found a reproducer for the following issue on: HEAD commit: ca4ee40bf13d Partly revert "drm/hyperv: Remove reference t.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=1575c722580000 kernel config: https://syzkaller.appspot.com/x/.config?x=4b4f2aab682301f1 dashboard link: https://syzkaller.appspot.com/bug?extid=1543a7d954d9c6d00407 compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1044ec02580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10e3fe5a580000
Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/68f5e4558a91/disk-ca4ee40b.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/ea1eab60444d/vmlinux-ca4ee40b.xz kernel image: https://storage.googleapis.com/syzbot-assets/cc7e3debdec4/bzImage-ca4ee40b.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: [email protected] ===================================================== BUG: KMSAN: uninit-value in gso_features_check net/core/dev.c:3804 [inline] BUG: KMSAN: uninit-value in netif_skb_features+0x6fb/0x1870 net/core/dev.c:3828 gso_features_check net/core/dev.c:3804 [inline] netif_skb_features+0x6fb/0x1870 net/core/dev.c:3828 validate_xmit_skb+0xb6/0x2400 net/core/dev.c:4003 validate_xmit_skb_list+0xd4/0x320 net/core/dev.c:4065 sch_direct_xmit+0xd4/0xcf0 net/sched/sch_generic.c:332 __dev_xmit_skb net/core/dev.c:4179 [inline] __dev_queue_xmit+0x3016/0x5a50 net/core/dev.c:4795 dev_queue_xmit include/linux/netdevice.h:3384 [inline] packet_xmit+0x8f/0x710 net/packet/af_packet.c:275 packet_snd net/packet/af_packet.c:3077 [inline] packet_sendmsg+0x91d9/0xa320 net/packet/af_packet.c:3109 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0xfe7/0x1080 net/socket.c:2592 ___sys_sendmsg+0x271/0x3b0 net/socket.c:2646 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __x64_sys_sendmsg+0x211/0x3e0 net/socket.c:2681 x64_sys_call+0x1e20/0x3ea0 arch/x86/include/generated/asm/syscalls_64.h:47 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x134/0xf80 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:4466 [inline] slab_alloc_node mm/slub.c:4788 [inline] kmem_cache_alloc_node_noprof+0x3cd/0x12d0 mm/slub.c:4840 kmalloc_reserve net/core/skbuff.c:613 [inline] __alloc_skb+0x855/0x1190 net/core/skbuff.c:713 alloc_skb include/linux/skbuff.h:1383 [inline] alloc_skb_with_frags+0xc5/0xa60 net/core/skbuff.c:6750 sock_alloc_send_pskb+0xacb/0xc60 net/core/sock.c:2995 packet_alloc_skb net/packet/af_packet.c:2927 [inline] packet_snd net/packet/af_packet.c:3020 [inline] packet_sendmsg+0x7477/0xa320 net/packet/af_packet.c:3109 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0xfe7/0x1080 net/socket.c:2592 ___sys_sendmsg+0x271/0x3b0 net/socket.c:2646 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __x64_sys_sendmsg+0x211/0x3e0 net/socket.c:2681 x64_sys_call+0x1e20/0x3ea0 arch/x86/include/generated/asm/syscalls_64.h:47 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x134/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f CPU: 0 UID: 0 PID: 6045 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 ===================================================== --- If you want syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing.
