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KMSAN: uninit-value in ip_tunnel_rcv (2)

Status: fixed on 2024/04/11 08:41
Subsystems: net
[Documentation on labels]
Fix commit: b0ec2abf9826 net: ip_tunnel: make sure to pull inner header in ip_tunnel_rcv()
First crash: 75d, last: 75d
Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KMSAN: uninit-value in ip_tunnel_rcv net C 7 113d 137d 0/26 closed as invalid on 2024/03/01 17:31
upstream KMSAN: uninit-value in IP6_ECN_decapsulate net C 981 153d 2069d 25/26 fixed on 2023/12/21 03:45

Sample crash report:
=====================================================
BUG: KMSAN: uninit-value in __INET_ECN_decapsulate include/net/inet_ecn.h:253 [inline]
BUG: KMSAN: uninit-value in INET_ECN_decapsulate include/net/inet_ecn.h:275 [inline]
BUG: KMSAN: uninit-value in IP_ECN_decapsulate include/net/inet_ecn.h:302 [inline]
BUG: KMSAN: uninit-value in ip_tunnel_rcv+0xed9/0x2ed0 net/ipv4/ip_tunnel.c:409
 __INET_ECN_decapsulate include/net/inet_ecn.h:253 [inline]
 INET_ECN_decapsulate include/net/inet_ecn.h:275 [inline]
 IP_ECN_decapsulate include/net/inet_ecn.h:302 [inline]
 ip_tunnel_rcv+0xed9/0x2ed0 net/ipv4/ip_tunnel.c:409
 __ipgre_rcv+0x9bc/0xbc0 net/ipv4/ip_gre.c:389
 ipgre_rcv net/ipv4/ip_gre.c:411 [inline]
 gre_rcv+0x423/0x19f0 net/ipv4/ip_gre.c:447
 gre_rcv+0x2a4/0x390 net/ipv4/gre_demux.c:163
 ip_protocol_deliver_rcu+0x264/0x1300 net/ipv4/ip_input.c:205
 ip_local_deliver_finish+0x2b8/0x440 net/ipv4/ip_input.c:233
 NF_HOOK include/linux/netfilter.h:314 [inline]
 ip_local_deliver+0x21f/0x490 net/ipv4/ip_input.c:254
 dst_input include/net/dst.h:461 [inline]
 ip_rcv_finish net/ipv4/ip_input.c:449 [inline]
 NF_HOOK include/linux/netfilter.h:314 [inline]
 ip_rcv+0x46f/0x760 net/ipv4/ip_input.c:569
 __netif_receive_skb_one_core net/core/dev.c:5534 [inline]
 __netif_receive_skb+0x1a6/0x5a0 net/core/dev.c:5648
 netif_receive_skb_internal net/core/dev.c:5734 [inline]
 netif_receive_skb+0x58/0x660 net/core/dev.c:5793
 tun_rx_batched+0x3ee/0x980 drivers/net/tun.c:1556
 tun_get_user+0x53b9/0x66e0 drivers/net/tun.c:2009
 tun_chr_write_iter+0x3af/0x5d0 drivers/net/tun.c:2055
 call_write_iter include/linux/fs.h:2087 [inline]
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0xb6b/0x1520 fs/read_write.c:590
 ksys_write+0x20f/0x4c0 fs/read_write.c:643
 __do_sys_write fs/read_write.c:655 [inline]
 __se_sys_write fs/read_write.c:652 [inline]
 __x64_sys_write+0x93/0xd0 fs/read_write.c:652
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

Uninit was created at:
 __alloc_pages+0x9a6/0xe00 mm/page_alloc.c:4590
 alloc_pages_mpol+0x62b/0x9d0 mm/mempolicy.c:2133
 alloc_pages+0x1be/0x1e0 mm/mempolicy.c:2204
 skb_page_frag_refill+0x2bf/0x7c0 net/core/sock.c:2909
 tun_build_skb drivers/net/tun.c:1686 [inline]
 tun_get_user+0xe0a/0x66e0 drivers/net/tun.c:1826
 tun_chr_write_iter+0x3af/0x5d0 drivers/net/tun.c:2055
 call_write_iter include/linux/fs.h:2087 [inline]
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0xb6b/0x1520 fs/read_write.c:590
 ksys_write+0x20f/0x4c0 fs/read_write.c:643
 __do_sys_write fs/read_write.c:655 [inline]
 __se_sys_write fs/read_write.c:652 [inline]
 __x64_sys_write+0x93/0xd0 fs/read_write.c:652
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

CPU: 1 PID: 7665 Comm: syz-executor.3 Not tainted 6.8.0-rc7-syzkaller-00020-g5847c9777c30 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
=====================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/03/07 00:31 upstream 5847c9777c30 f39a7eed .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in ip_tunnel_rcv
* Struck through repros no longer work on HEAD.