Hello,
syzbot found the following crash on:
HEAD commit: 05f22368 x86, kcsan: Enable KCSAN for x86
git tree: https://github.com/google/ktsan.git kcsan
console output: https://syzkaller.appspot.com/x/log.txt?x=17f9952f600000
kernel config: https://syzkaller.appspot.com/x/.config?x=87d111955f40591f
dashboard link: https://syzkaller.appspot.com/bug?extid=0b3bfb9cbec193033650
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
Unfortunately, I don't have any reproducer for this crash yet.
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+0b3bfb9cbec193033650@xxxxxxxxxxxxxxxxxxxxxxxxx
IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): bridge_slave_0: link becomes ready
==================================================================
BUG: KCSAN: data-race in pcpu_alloc / pcpu_free_area
write to 0xffffffff86046740 of 4 bytes by task 7371 on cpu 0:
pcpu_update_empty_pages mm/percpu.c:575 [inline]
pcpu_block_update_hint_free mm/percpu.c:1012 [inline]
pcpu_free_area+0x448/0x6a0 mm/percpu.c:1267
free_percpu mm/percpu.c:1975 [inline]
free_percpu+0x152/0x440 mm/percpu.c:1955
xt_percpu_counter_free+0x82/0xa0 net/netfilter/x_tables.c:1862
cleanup_entry+0x12a/0x160 net/ipv6/netfilter/ip6_tables.c:672
__do_replace+0x439/0x510 net/ipv6/netfilter/ip6_tables.c:1102
do_replace net/ipv6/netfilter/ip6_tables.c:1157 [inline]
do_ip6t_set_ctl+0x26d/0x311 net/ipv6/netfilter/ip6_tables.c:1681
nf_sockopt net/netfilter/nf_sockopt.c:106 [inline]
nf_setsockopt+0x6e/0xb0 net/netfilter/nf_sockopt.c:115
ipv6_setsockopt net/ipv6/ipv6_sockglue.c:949 [inline]
ipv6_setsockopt+0x119/0x130 net/ipv6/ipv6_sockglue.c:933
tcp_setsockopt net/ipv4/tcp.c:3148 [inline]
tcp_setsockopt+0x7c/0xc0 net/ipv4/tcp.c:3142
sock_common_setsockopt+0x67/0x90 net/core/sock.c:3147
__sys_setsockopt+0x1ce/0x370 net/socket.c:2084
__do_sys_setsockopt net/socket.c:2100 [inline]
__se_sys_setsockopt net/socket.c:2097 [inline]
__x64_sys_setsockopt+0x70/0x90 net/socket.c:2097
do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x44/0xa9
read to 0xffffffff86046740 of 4 bytes by task 44 on cpu 1:
pcpu_alloc+0x3b0/0xcf0 mm/percpu.c:1729
__alloc_percpu_gfp+0x31/0x50 mm/percpu.c:1783
fib_nh_common_init+0x58/0x1e0 net/ipv4/fib_semantics.c:572
fib6_nh_init+0x2aa/0xee0 net/ipv6/route.c:3466
ip6_route_info_create+0x913/0xd40 net/ipv6/route.c:3655
ip6_route_add+0x30/0xd0 net/ipv6/route.c:3695
addrconf_add_mroute+0x177/0x1a0 net/ipv6/addrconf.c:2459
addrconf_add_dev+0x100/0x170 net/ipv6/addrconf.c:2477
addrconf_dev_config+0x170/0x280 net/ipv6/addrconf.c:3351
addrconf_notify+0x1fa/0x1480 net/ipv6/addrconf.c:3595
notifier_call_chain+0xd7/0x160 kernel/notifier.c:95
__raw_notifier_call_chain kernel/notifier.c:396 [inline]
raw_notifier_call_chain+0x37/0x50 kernel/notifier.c:403
call_netdevice_notifiers_info+0x48/0xc0 net/core/dev.c:1749
Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 44 Comm: kworker/1:1 Not tainted 5.4.0-rc3+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Workqueue: events linkwatch_event
==================================================================
---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx.
syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
