KMSAN: uninit-value in ip_route_output_key_hash

KMSAN: uninit-value in ip_route_output_key_hash_rcu (4)
Status: upstream: reported on 2021/01/13 20:47
Reported-by: syzbot+549e451574ba8bfd0fd6@syzkaller.appspotmail.com
First crash: 95d, last: 73d

similar bugs (3):
Kernel	Title	Count	Last	Reported	Patched	Status
upstream	KMSAN: uninit-value in ip_route_output_key_hash_rcu (2)	1	1064d	1064d	0/22	closed as invalid on 2018/06/27 15:18
upstream	KMSAN: uninit-value in ip_route_output_key_hash_rcu (3)	2	390d	415d	0/22	auto-closed as invalid on 2020/06/19 03:56
upstream	KMSAN: uninit-value in ip_route_output_key_hash_rcu	179	1072d	1103d	6/22	fixed on 2018/05/08 18:30

Sample crash report:

=====================================================
BUG: KMSAN: uninit-value in ip_route_output_key_hash_rcu+0xe5a/0x1ef0 net/ipv4/route.c:2588
CPU: 1 PID: 10940 Comm: syz-executor.3 Not tainted 5.10.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x21c/0x280 lib/dump_stack.c:118
 kmsan_report+0xfb/0x1e0 mm/kmsan/kmsan_report.c:118
 __msan_warning+0x5f/0xa0 mm/kmsan/kmsan_instr.c:197
 ip_route_output_key_hash_rcu+0xe5a/0x1ef0 net/ipv4/route.c:2588
 ip_route_output_key_hash+0x21b/0x2d0 net/ipv4/route.c:2507
 __ip_route_output_key include/net/route.h:126 [inline]
 xfrmi_xmit+0x4cf/0x1fd0 net/xfrm/xfrm_interface.c:376
 __netdev_start_xmit include/linux/netdevice.h:4718 [inline]
 netdev_start_xmit include/linux/netdevice.h:4732 [inline]
 xmit_one+0x2b6/0x760 net/core/dev.c:3564
 dev_hard_start_xmit net/core/dev.c:3580 [inline]
 __dev_queue_xmit+0x3426/0x4590 net/core/dev.c:4140
 dev_queue_xmit+0x4b/0x60 net/core/dev.c:4173
 packet_snd net/packet/af_packet.c:2992 [inline]
 packet_sendmsg+0x8778/0x9a60 net/packet/af_packet.c:3017
 sock_sendmsg_nosec net/socket.c:651 [inline]
 sock_sendmsg net/socket.c:671 [inline]
 ____sys_sendmsg+0xcfc/0x12f0 net/socket.c:2353
 ___sys_sendmsg net/socket.c:2407 [inline]
 __sys_sendmsg+0x6f1/0x840 net/socket.c:2440
 __do_sys_sendmsg net/socket.c:2449 [inline]
 __se_sys_sendmsg+0x97/0xb0 net/socket.c:2447
 __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2447
 do_syscall_64+0x9f/0x140 arch/x86/entry/common.c:48
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45e219
Code: 0d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 db b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f78eaed0c68 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045e219
RDX: 0000000000000000 RSI: 0000000020000580 RDI: 0000000000000003
RBP: 000000000119c068 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000119c034
R13: 00000000016afb5f R14: 00007f78eaed19c0 R15: 000000000119c034

Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:121 [inline]
 kmsan_internal_chain_origin+0xad/0x130 mm/kmsan/kmsan.c:289
 __msan_chain_origin+0x57/0xa0 mm/kmsan/kmsan_instr.c:147
 decode_session4 net/xfrm/xfrm_policy.c:3285 [inline]
 __xfrm_decode_session+0x1750/0x37c0 net/xfrm/xfrm_policy.c:3481
 xfrm_decode_session include/net/xfrm.h:1137 [inline]
 xfrmi_xmit+0x243/0x1fd0 net/xfrm/xfrm_interface.c:369
 __netdev_start_xmit include/linux/netdevice.h:4718 [inline]
 netdev_start_xmit include/linux/netdevice.h:4732 [inline]
 xmit_one+0x2b6/0x760 net/core/dev.c:3564
 dev_hard_start_xmit net/core/dev.c:3580 [inline]
 __dev_queue_xmit+0x3426/0x4590 net/core/dev.c:4140
 dev_queue_xmit+0x4b/0x60 net/core/dev.c:4173
 packet_snd net/packet/af_packet.c:2992 [inline]
 packet_sendmsg+0x8778/0x9a60 net/packet/af_packet.c:3017
 sock_sendmsg_nosec net/socket.c:651 [inline]
 sock_sendmsg net/socket.c:671 [inline]
 ____sys_sendmsg+0xcfc/0x12f0 net/socket.c:2353
 ___sys_sendmsg net/socket.c:2407 [inline]
 __sys_sendmsg+0x6f1/0x840 net/socket.c:2440
 __do_sys_sendmsg net/socket.c:2449 [inline]
 __se_sys_sendmsg+0x97/0xb0 net/socket.c:2447
 __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2447
 do_syscall_64+0x9f/0x140 arch/x86/entry/common.c:48
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:121 [inline]
 kmsan_internal_poison_shadow+0x5c/0xf0 mm/kmsan/kmsan.c:104
 kmsan_slab_alloc+0x8d/0xe0 mm/kmsan/kmsan_hooks.c:76
 slab_alloc_node mm/slub.c:2906 [inline]
 __kmalloc_node_track_caller+0xa48/0x1610 mm/slub.c:4512
 __kmalloc_reserve net/core/skbuff.c:142 [inline]
 __alloc_skb+0x318/0xb00 net/core/skbuff.c:210
 alloc_skb include/linux/skbuff.h:1094 [inline]
 alloc_skb_with_frags+0x1f3/0xc10 net/core/skbuff.c:5832
 sock_alloc_send_pskb+0xcc4/0xe80 net/core/sock.c:2329
 packet_alloc_skb net/packet/af_packet.c:2840 [inline]
 packet_snd net/packet/af_packet.c:2935 [inline]
 packet_sendmsg+0x6aab/0x9a60 net/packet/af_packet.c:3017
 sock_sendmsg_nosec net/socket.c:651 [inline]
 sock_sendmsg net/socket.c:671 [inline]
 ____sys_sendmsg+0xcfc/0x12f0 net/socket.c:2353
 ___sys_sendmsg net/socket.c:2407 [inline]
 __sys_sendmsg+0x6f1/0x840 net/socket.c:2440
 __do_sys_sendmsg net/socket.c:2449 [inline]
 __se_sys_sendmsg+0x97/0xb0 net/socket.c:2447
 __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2447
 do_syscall_64+0x9f/0x140 arch/x86/entry/common.c:48
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
=====================================================

Crashes (2):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Title
ci-upstream-kmsan-gce	2021/02/01 04:16	https://github.com/google/kmsan.git master	73d62e81	fc9fd31e	.config	log	report			info	KMSAN: uninit-value in ip_route_output_key_hash_rcu
ci-upstream-kmsan-gce	2021/01/09 19:12	https://github.com/google/kmsan.git master	73d62e81	2c1f2513	.config	log	report			info