From: Ben Hutchings <ben@decadent.org.uk>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: akpm@linux-foundation.org, Denis Kirjanov <kda@linux-powerpc.org>,
"Eric Dumazet" <edumazet@google.com>,
"David S. Miller" <davem@davemloft.net>
Subject: [PATCH 3.16 06/10] ipv4: fix a race in update_or_create_fnhe()
Date: Thu, 09 May 2019 15:08:17 +0100 [thread overview]
Message-ID: <lsq.1557410897.156917509@decadent.org.uk> (raw)
In-Reply-To: <lsq.1557410896.171359878@decadent.org.uk>
3.16.67-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Eric Dumazet <edumazet@google.com>
commit caa415270c732505240bb60171c44a7838c555e8 upstream.
nh_exceptions is effectively used under rcu, but lacks proper
barriers. Between kzalloc() and setting of nh->nh_exceptions(),
we need a proper memory barrier.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Fixes: 4895c771c7f00 ("ipv4: Add FIB nexthop exceptions.")
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
include/net/ip_fib.h | 2 +-
net/ipv4/fib_semantics.c | 8 +++++---
net/ipv4/route.c | 6 +++---
3 files changed, 9 insertions(+), 7 deletions(-)
--- a/include/net/ip_fib.h
+++ b/include/net/ip_fib.h
@@ -89,7 +89,7 @@ struct fib_nh {
int nh_saddr_genid;
struct rtable __rcu * __percpu *nh_pcpu_rth_output;
struct rtable __rcu *nh_rth_input;
- struct fnhe_hash_bucket *nh_exceptions;
+ struct fnhe_hash_bucket __rcu *nh_exceptions;
};
/*
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -157,9 +157,12 @@ static void rt_fibinfo_free(struct rtabl
static void free_nh_exceptions(struct fib_nh *nh)
{
- struct fnhe_hash_bucket *hash = nh->nh_exceptions;
+ struct fnhe_hash_bucket *hash;
int i;
+ hash = rcu_dereference_protected(nh->nh_exceptions, 1);
+ if (!hash)
+ return;
for (i = 0; i < FNHE_HASH_SIZE; i++) {
struct fib_nh_exception *fnhe;
@@ -206,8 +209,7 @@ static void free_fib_info_rcu(struct rcu
change_nexthops(fi) {
if (nexthop_nh->nh_dev)
dev_put(nexthop_nh->nh_dev);
- if (nexthop_nh->nh_exceptions)
- free_nh_exceptions(nexthop_nh);
+ free_nh_exceptions(nexthop_nh);
rt_fibinfo_free_cpus(nexthop_nh->nh_pcpu_rth_output);
rt_fibinfo_free(&nexthop_nh->nh_rth_input);
} endfor_nexthops(fi);
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -635,12 +635,12 @@ static void update_or_create_fnhe(struct
spin_lock_bh(&fnhe_lock);
- hash = nh->nh_exceptions;
+ hash = rcu_dereference(nh->nh_exceptions);
if (!hash) {
hash = kzalloc(FNHE_HASH_SIZE * sizeof(*hash), GFP_ATOMIC);
if (!hash)
goto out_unlock;
- nh->nh_exceptions = hash;
+ rcu_assign_pointer(nh->nh_exceptions, hash);
}
hash += hval;
@@ -1293,7 +1293,7 @@ static void ip_del_fnhe(struct fib_nh *n
static struct fib_nh_exception *find_exception(struct fib_nh *nh, __be32 daddr)
{
- struct fnhe_hash_bucket *hash = nh->nh_exceptions;
+ struct fnhe_hash_bucket *hash = rcu_dereference(nh->nh_exceptions);
struct fib_nh_exception *fnhe;
u32 hval;
next prev parent reply other threads:[~2019-05-09 14:13 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-09 14:08 [PATCH 3.16 00/10] 3.16.67-rc1 review Ben Hutchings
2019-05-09 14:08 ` [PATCH 3.16 08/10] fork: record start_time late Ben Hutchings
2019-05-09 14:08 ` [PATCH 3.16 09/10] timer/debug: Change /proc/timer_stats from 0644 to 0600 Ben Hutchings
2019-05-09 14:08 ` [PATCH 3.16 10/10] percpu: stop printing kernel addresses Ben Hutchings
2019-05-09 14:08 ` [PATCH 3.16 04/10] spi: omap-100k: Remove unused definitions Ben Hutchings
2019-05-09 14:08 ` [PATCH 3.16 03/10] inet: update the IP ID generation algorithm to higher standards Ben Hutchings
2019-05-09 14:08 ` [PATCH 3.16 07/10] KVM: VMX: Fix x2apic check in vmx_msr_bitmap_mode() Ben Hutchings
2019-05-09 14:08 ` [PATCH 3.16 05/10] vxlan: Fix big-endian declaration of VNI Ben Hutchings
2019-05-09 14:08 ` [PATCH 3.16 01/10] Revert "brcmfmac: assure SSID length from firmware is limited" Ben Hutchings
2019-05-09 14:08 ` [PATCH 3.16 02/10] brcmfmac: add length checks in scheduled scan result handler Ben Hutchings
2019-05-09 14:08 ` Ben Hutchings [this message]
2019-05-09 17:38 ` [PATCH 3.16 00/10] 3.16.67-rc1 review Guenter Roeck
2019-05-09 19:00 ` Ben Hutchings
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