syzbot


KCSAN: data-race in tcp_v4_rcv / tcp_v4_rcv

Status: fixed on 2019/11/23 02:56
Subsystems: net
[Documentation on labels]
Fix commit: 7170a977743b net-backports: net: annotate accesses to sk->sk_incoming_cpu
First crash: 1724d, last: 1716d

Sample crash report:
==================================================================
BUG: KCSAN: data-race in tcp_v4_rcv / tcp_v4_rcv

write to 0xffff8880a5fcd37c of 4 bytes by interrupt on cpu 1:
 sk_incoming_cpu_update include/net/sock.h:953 [inline]
 tcp_v4_rcv+0x1b3c/0x1bb0 net/ipv4/tcp_ipv4.c:1934
 ip_protocol_deliver_rcu+0x4d/0x420 net/ipv4/ip_input.c:204
 ip_local_deliver_finish+0x110/0x140 net/ipv4/ip_input.c:231
 NF_HOOK include/linux/netfilter.h:305 [inline]
 NF_HOOK include/linux/netfilter.h:299 [inline]
 ip_local_deliver+0x133/0x210 net/ipv4/ip_input.c:252
 dst_input include/net/dst.h:442 [inline]
 ip_rcv_finish+0x121/0x160 net/ipv4/ip_input.c:413
 NF_HOOK include/linux/netfilter.h:305 [inline]
 NF_HOOK include/linux/netfilter.h:299 [inline]
 ip_rcv+0x18f/0x1a0 net/ipv4/ip_input.c:523
 __netif_receive_skb_one_core+0xa7/0xe0 net/core/dev.c:5010
 __netif_receive_skb+0x37/0xf0 net/core/dev.c:5124
 process_backlog+0x1d3/0x420 net/core/dev.c:5955
 napi_poll net/core/dev.c:6392 [inline]
 net_rx_action+0x3ae/0xa90 net/core/dev.c:6460
 __do_softirq+0x115/0x33f kernel/softirq.c:292
 do_softirq_own_stack+0x2a/0x40 arch/x86/entry/entry_64.S:1082
 do_softirq.part.0+0x6b/0x80 kernel/softirq.c:337
 do_softirq kernel/softirq.c:329 [inline]
 __local_bh_enable_ip+0x76/0x80 kernel/softirq.c:189

read to 0xffff8880a5fcd37c of 4 bytes by interrupt on cpu 0:
 sk_incoming_cpu_update include/net/sock.h:952 [inline]
 tcp_v4_rcv+0x181a/0x1bb0 net/ipv4/tcp_ipv4.c:1934
 ip_protocol_deliver_rcu+0x4d/0x420 net/ipv4/ip_input.c:204
 ip_local_deliver_finish+0x110/0x140 net/ipv4/ip_input.c:231
 NF_HOOK include/linux/netfilter.h:305 [inline]
 NF_HOOK include/linux/netfilter.h:299 [inline]
 ip_local_deliver+0x133/0x210 net/ipv4/ip_input.c:252
 dst_input include/net/dst.h:442 [inline]
 ip_rcv_finish+0x121/0x160 net/ipv4/ip_input.c:413
 NF_HOOK include/linux/netfilter.h:305 [inline]
 NF_HOOK include/linux/netfilter.h:299 [inline]
 ip_rcv+0x18f/0x1a0 net/ipv4/ip_input.c:523
 __netif_receive_skb_one_core+0xa7/0xe0 net/core/dev.c:5010
 __netif_receive_skb+0x37/0xf0 net/core/dev.c:5124
 process_backlog+0x1d3/0x420 net/core/dev.c:5955
 napi_poll net/core/dev.c:6392 [inline]
 net_rx_action+0x3ae/0xa90 net/core/dev.c:6460
 __do_softirq+0x115/0x33f kernel/softirq.c:292
 run_ksoftirqd+0x46/0x60 kernel/softirq.c:603
 smpboot_thread_fn+0x37d/0x4a0 kernel/smpboot.c:165

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 9 Comm: ksoftirqd/0 Not tainted 5.4.0-rc3+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2019/11/03 17:28 https://github.com/google/ktsan.git kcsan 05f2236801fe c9610487 .config console log report ci2-upstream-kcsan-gce
2019/11/02 01:59 https://github.com/google/ktsan.git kcsan 05f2236801fe 997ccc67 .config console log report ci2-upstream-kcsan-gce
2019/10/29 09:30 https://github.com/google/ktsan.git kcsan 05f2236801fe 5ea87a66 .config console log report ci2-upstream-kcsan-gce
2019/10/26 18:30 https://github.com/google/ktsan.git kcsan 05f2236801fe 25bb509e .config console log report ci2-upstream-kcsan-gce
* Struck through repros no longer work on HEAD.