KMSAN: uninit-value in __ipv6_addr_type

Status: fixed on 2025/06/10 16:19
Subsystems: net
[Documentation on labels]
Reported-by: syzbot+93ab4a777bafb9d9f960@syzkaller.appspotmail.com
Fix commit: 27843ce6ba3d ipvlan: ensure network headers are in skb linear part
First crash: 533d, last: 532d
▶ ▼ Discussions (2)
Title Replies (including bot) Last reply
[PATCH net] ipvlan: ensure network headers are in skb linear part 2 (2) 2025/02/22 00:50
[syzbot] [net?] KMSAN: uninit-value in __ipv6_addr_type 0 (2) 2025/02/20 17:14
▶ ▼ Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KMSAN: kernel-infoleak in copyout (2) net 17 syz, C 6723 1156d 2324d 22/29 fixed on 2023/06/08 14:41
upstream KMSAN: kernel-infoleak in _copy_to_iter (7) net 21 syz, C 138977 1259d 1612d 22/29 fixed on 2023/02/24 13:50
upstream KMSAN: uninit-value in IP6_ECN_decapsulate net 7 syz, C 981 961d 2877d 25/29 fixed on 2023/12/21 03:45

Sample crash report:
=====================================================
BUG: KMSAN: uninit-value in __ipv6_addr_type+0xa2/0x490 net/ipv6/addrconf_core.c:47
 __ipv6_addr_type+0xa2/0x490 net/ipv6/addrconf_core.c:47
 ipv6_addr_type include/net/ipv6.h:555 [inline]
 ip6_route_output_flags_noref net/ipv6/route.c:2616 [inline]
 ip6_route_output_flags+0x51/0x720 net/ipv6/route.c:2651
 ip6_route_output include/net/ip6_route.h:93 [inline]
 ipvlan_route_v6_outbound+0x24e/0x520 drivers/net/ipvlan/ipvlan_core.c:476
 ipvlan_process_v6_outbound drivers/net/ipvlan/ipvlan_core.c:491 [inline]
 ipvlan_process_outbound drivers/net/ipvlan/ipvlan_core.c:541 [inline]
 ipvlan_xmit_mode_l3 drivers/net/ipvlan/ipvlan_core.c:605 [inline]
 ipvlan_queue_xmit+0xd72/0x1780 drivers/net/ipvlan/ipvlan_core.c:671
 ipvlan_start_xmit+0x5b/0x210 drivers/net/ipvlan/ipvlan_main.c:223
 __netdev_start_xmit include/linux/netdevice.h:5150 [inline]
 netdev_start_xmit include/linux/netdevice.h:5159 [inline]
 xmit_one net/core/dev.c:3735 [inline]
 dev_hard_start_xmit+0x247/0xa20 net/core/dev.c:3751
 __dev_queue_xmit+0x366a/0x57d0 net/core/dev.c:4584
 dev_queue_xmit include/linux/netdevice.h:3311 [inline]
 packet_xmit+0x9c/0x6c0 net/packet/af_packet.c:276
 packet_snd net/packet/af_packet.c:3132 [inline]
 packet_sendmsg+0x93e0/0xa7e0 net/packet/af_packet.c:3164
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg+0x30f/0x380 net/socket.c:733
 __sys_sendto+0x594/0x750 net/socket.c:2187
 __do_sys_sendto net/socket.c:2194 [inline]
 __se_sys_sendto net/socket.c:2190 [inline]
 __x64_sys_sendto+0x125/0x1d0 net/socket.c:2190
 x64_sys_call+0x346a/0x3c30 arch/x86/include/generated/asm/syscalls_64.h:45
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was stored to memory at:
 ipvlan_route_v6_outbound+0x18f/0x520 drivers/net/ipvlan/ipvlan_core.c:466
 ipvlan_process_v6_outbound drivers/net/ipvlan/ipvlan_core.c:491 [inline]
 ipvlan_process_outbound drivers/net/ipvlan/ipvlan_core.c:541 [inline]
 ipvlan_xmit_mode_l3 drivers/net/ipvlan/ipvlan_core.c:605 [inline]
 ipvlan_queue_xmit+0xd72/0x1780 drivers/net/ipvlan/ipvlan_core.c:671
 ipvlan_start_xmit+0x5b/0x210 drivers/net/ipvlan/ipvlan_main.c:223
 __netdev_start_xmit include/linux/netdevice.h:5150 [inline]
 netdev_start_xmit include/linux/netdevice.h:5159 [inline]
 xmit_one net/core/dev.c:3735 [inline]
 dev_hard_start_xmit+0x247/0xa20 net/core/dev.c:3751
 __dev_queue_xmit+0x366a/0x57d0 net/core/dev.c:4584
 dev_queue_xmit include/linux/netdevice.h:3311 [inline]
 packet_xmit+0x9c/0x6c0 net/packet/af_packet.c:276
 packet_snd net/packet/af_packet.c:3132 [inline]
 packet_sendmsg+0x93e0/0xa7e0 net/packet/af_packet.c:3164
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg+0x30f/0x380 net/socket.c:733
 __sys_sendto+0x594/0x750 net/socket.c:2187
 __do_sys_sendto net/socket.c:2194 [inline]
 __se_sys_sendto net/socket.c:2190 [inline]
 __x64_sys_sendto+0x125/0x1d0 net/socket.c:2190
 x64_sys_call+0x346a/0x3c30 arch/x86/include/generated/asm/syscalls_64.h:45
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:4121 [inline]
 slab_alloc_node mm/slub.c:4164 [inline]
 kmem_cache_alloc_node_noprof+0x907/0xe00 mm/slub.c:4216
 kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:587
 __alloc_skb+0x363/0x7b0 net/core/skbuff.c:678
 alloc_skb include/linux/skbuff.h:1331 [inline]
 alloc_skb_with_frags+0xc8/0xd00 net/core/skbuff.c:6612
 sock_alloc_send_pskb+0xa81/0xbf0 net/core/sock.c:2897
 packet_alloc_skb net/packet/af_packet.c:2981 [inline]
 packet_snd net/packet/af_packet.c:3075 [inline]
 packet_sendmsg+0x7722/0xa7e0 net/packet/af_packet.c:3164
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg+0x30f/0x380 net/socket.c:733
 __sys_sendto+0x594/0x750 net/socket.c:2187
 __do_sys_sendto net/socket.c:2194 [inline]
 __se_sys_sendto net/socket.c:2190 [inline]
 __x64_sys_sendto+0x125/0x1d0 net/socket.c:2190
 x64_sys_call+0x346a/0x3c30 arch/x86/include/generated/asm/syscalls_64.h:45
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 0 UID: 0 PID: 5860 Comm: syz-executor330 Not tainted 6.14.0-rc3-syzkaller-00079-g87a132e73910 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
=====================================================

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/02/20 22:38 upstream 87a132e73910 50668798 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in __ipv6_addr_type
2025/02/20 17:13 upstream 87a132e73910 50668798 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in __ipv6_addr_type
2025/02/20 02:59 upstream 6537cfb395f3 cbd8edab .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in __ipv6_addr_type
* Struck through repros no longer work on HEAD.