syzbot


KMSAN: uninit-value in llc_station_rcv

Status: fixed on 2023/12/21 01:43
Subsystems: net
[Documentation on labels]
Fix commit: 7b3ba18703a6 llc: verify mac len before reading mac header
First crash: 136d, last: 122d
Discussions (2)
Title Replies (including bot) Last reply
[PATCH net v2] llc: verify mac len before reading mac header 2 (2) 2023/11/02 05:51
[PATCH net] llc: verify mac len before reading mac header 8 (8) 2023/10/25 23:18
Last patch testing requests (1)
Created Duration User Patch Repo Result
2023/10/26 22:15 17m retest repro upstream report log

Sample crash report:
syz-executor154 uses obsolete (PF_INET,SOCK_PACKET)
=====================================================
BUG: KMSAN: uninit-value in llc_station_ac_send_test_r net/llc/llc_station.c:81 [inline]
BUG: KMSAN: uninit-value in llc_station_rcv+0x6fb/0x1290 net/llc/llc_station.c:111
 llc_station_ac_send_test_r net/llc/llc_station.c:81 [inline]
 llc_station_rcv+0x6fb/0x1290 net/llc/llc_station.c:111
 llc_rcv+0xc5d/0x14a0 net/llc/llc_input.c:218
 __netif_receive_skb_one_core net/core/dev.c:5523 [inline]
 __netif_receive_skb+0x1a6/0x5a0 net/core/dev.c:5637
 netif_receive_skb_internal net/core/dev.c:5723 [inline]
 netif_receive_skb+0x58/0x660 net/core/dev.c:5782
 tun_rx_batched+0x3ee/0x980 drivers/net/tun.c:1555
 tun_get_user+0x54c5/0x69c0 drivers/net/tun.c:2002
 tun_chr_write_iter+0x3af/0x5d0 drivers/net/tun.c:2048
 call_write_iter include/linux/fs.h:1956 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x8ef/0x15c0 fs/read_write.c:584
 ksys_write+0x20f/0x4c0 fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __x64_sys_write+0x93/0xd0 fs/read_write.c:646
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Uninit was created at:
 slab_post_alloc_hook+0x12f/0xb70 mm/slab.h:767
 slab_alloc_node mm/slub.c:3478 [inline]
 kmem_cache_alloc_node+0x577/0xa80 mm/slub.c:3523
 kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:559
 __alloc_skb+0x318/0x740 net/core/skbuff.c:650
 alloc_skb include/linux/skbuff.h:1286 [inline]
 alloc_skb_with_frags+0xc8/0xbd0 net/core/skbuff.c:6313
 sock_alloc_send_pskb+0xa80/0xbf0 net/core/sock.c:2795
 tun_alloc_skb drivers/net/tun.c:1531 [inline]
 tun_get_user+0x23d0/0x69c0 drivers/net/tun.c:1846
 tun_chr_write_iter+0x3af/0x5d0 drivers/net/tun.c:2048
 call_write_iter include/linux/fs.h:1956 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x8ef/0x15c0 fs/read_write.c:584
 ksys_write+0x20f/0x4c0 fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __x64_sys_write+0x93/0xd0 fs/read_write.c:646
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

CPU: 0 PID: 4998 Comm: syz-executor154 Not tainted 6.6.0-rc5-syzkaller-00072-g401644852d0b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023
=====================================================

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/10/12 20:10 upstream 401644852d0b fc170927 .config strace log report syz C [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce KMSAN: uninit-value in llc_station_rcv
2023/10/12 17:38 upstream 401644852d0b fc170927 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce KMSAN: uninit-value in llc_station_rcv
* Struck through repros no longer work on HEAD.