From: Eric Dumazet edumazet@google.com
[ Upstream commit c24b75e0f9239e78105f81c5f03a751641eb07ef ]
syzbot reported the following issue :
BUG: KCSAN: data-race in update_defense_level / update_defense_level
read to 0xffffffff861a6260 of 4 bytes by task 3006 on cpu 1: update_defense_level+0x621/0xb30 net/netfilter/ipvs/ip_vs_ctl.c:177 defense_work_handler+0x3d/0xd0 net/netfilter/ipvs/ip_vs_ctl.c:225 process_one_work+0x3d4/0x890 kernel/workqueue.c:2269 worker_thread+0xa0/0x800 kernel/workqueue.c:2415 kthread+0x1d4/0x200 drivers/block/aoe/aoecmd.c:1253 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352
write to 0xffffffff861a6260 of 4 bytes by task 7333 on cpu 0: update_defense_level+0xa62/0xb30 net/netfilter/ipvs/ip_vs_ctl.c:205 defense_work_handler+0x3d/0xd0 net/netfilter/ipvs/ip_vs_ctl.c:225 process_one_work+0x3d4/0x890 kernel/workqueue.c:2269 worker_thread+0xa0/0x800 kernel/workqueue.c:2415 kthread+0x1d4/0x200 drivers/block/aoe/aoecmd.c:1253 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352
Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 7333 Comm: kworker/0:5 Not tainted 5.4.0-rc3+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events defense_work_handler
Indeed, old_secure_tcp is currently a static variable, while it needs to be a per netns variable.
Fixes: a0840e2e165a ("IPVS: netns, ip_vs_ctl local vars moved to ipvs struct.") Signed-off-by: Eric Dumazet edumazet@google.com Reported-by: syzbot syzkaller@googlegroups.com Signed-off-by: Simon Horman horms@verge.net.au Signed-off-by: Sasha Levin sashal@kernel.org --- include/net/ip_vs.h | 1 + net/netfilter/ipvs/ip_vs_ctl.c | 15 +++++++-------- 2 files changed, 8 insertions(+), 8 deletions(-)
diff --git a/include/net/ip_vs.h b/include/net/ip_vs.h index 82bc9f0e8a769..f4e5ac8aa3668 100644 --- a/include/net/ip_vs.h +++ b/include/net/ip_vs.h @@ -891,6 +891,7 @@ struct netns_ipvs { struct delayed_work defense_work; /* Work handler */ int drop_rate; int drop_counter; + int old_secure_tcp; atomic_t dropentry; /* locks in ctl.c */ spinlock_t dropentry_lock; /* drop entry handling */ diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c index 6155fd6386bf4..5ec80818ace2c 100644 --- a/net/netfilter/ipvs/ip_vs_ctl.c +++ b/net/netfilter/ipvs/ip_vs_ctl.c @@ -98,7 +98,6 @@ static bool __ip_vs_addr_is_local_v6(struct net *net, static void update_defense_level(struct netns_ipvs *ipvs) { struct sysinfo i; - static int old_secure_tcp = 0; int availmem; int nomem; int to_change = -1; @@ -179,35 +178,35 @@ static void update_defense_level(struct netns_ipvs *ipvs) spin_lock(&ipvs->securetcp_lock); switch (ipvs->sysctl_secure_tcp) { case 0: - if (old_secure_tcp >= 2) + if (ipvs->old_secure_tcp >= 2) to_change = 0; break; case 1: if (nomem) { - if (old_secure_tcp < 2) + if (ipvs->old_secure_tcp < 2) to_change = 1; ipvs->sysctl_secure_tcp = 2; } else { - if (old_secure_tcp >= 2) + if (ipvs->old_secure_tcp >= 2) to_change = 0; } break; case 2: if (nomem) { - if (old_secure_tcp < 2) + if (ipvs->old_secure_tcp < 2) to_change = 1; } else { - if (old_secure_tcp >= 2) + if (ipvs->old_secure_tcp >= 2) to_change = 0; ipvs->sysctl_secure_tcp = 1; } break; case 3: - if (old_secure_tcp < 2) + if (ipvs->old_secure_tcp < 2) to_change = 1; break; } - old_secure_tcp = ipvs->sysctl_secure_tcp; + ipvs->old_secure_tcp = ipvs->sysctl_secure_tcp; if (to_change >= 0) ip_vs_protocol_timeout_change(ipvs, ipvs->sysctl_secure_tcp > 1);