On 06/06/2017 05:27 PM, Eric Dumazet wrote:
On Tue, 2017-06-06 at 18:00 -0600, David Ahern wrote:
On 6/6/17 3:06 PM, Ben Greear wrote:
This bug has been around forever, and we recently got an intern and
stuck him with
trying to reproduce it on the latest kernel. It is still here. I'm not
super excited
about trying to fix this, but we can easily test patches if someone has a
patch to try.
Can you try this (whitespace damaged on paste, but it is moving the lock
ahead of the fn_sernum check):
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index deea901746c8..7a44c49055c0 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -378,6 +378,7 @@ static int fib6_dump_table(struct fib6_table *table,
struct sk_buff *skb,
cb->args[5] = w->root->fn_sernum;
}
} else {
+ read_lock_bh(&table->tb6_lock);
if (cb->args[5] != w->root->fn_sernum) {
/* Begin at the root if the tree changed */
cb->args[5] = w->root->fn_sernum;
@@ -387,7 +388,6 @@ static int fib6_dump_table(struct fib6_table *table,
struct sk_buff *skb,
} else
w->skip = 0;
- read_lock_bh(&table->tb6_lock);
res = fib6_walk_continue(w);
read_unlock_bh(&table->tb6_lock);
if (res <= 0) {
Good catch, but it looks like similar fix is needed a few lines before.
We will test this tomorrow.
Thanks,
Ben
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index
deea901746c8570c5e801e40592c91e3b62812e0..b214443dc8346cef3690df7f27cc48a864028865
100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -372,12 +372,13 @@ static int fib6_dump_table(struct fib6_table *table,
struct sk_buff *skb,
read_lock_bh(&table->tb6_lock);
res = fib6_walk(net, w);
- read_unlock_bh(&table->tb6_lock);
if (res > 0) {
cb->args[4] = 1;
cb->args[5] = w->root->fn_sernum;
}
+ read_unlock_bh(&table->tb6_lock);
} else {
+ read_lock_bh(&table->tb6_lock);
if (cb->args[5] != w->root->fn_sernum) {
/* Begin at the root if the tree changed */
cb->args[5] = w->root->fn_sernum;
@@ -387,7 +388,6 @@ static int fib6_dump_table(struct fib6_table *table, struct
sk_buff *skb,
} else
w->skip = 0;
- read_lock_bh(&table->tb6_lock);
res = fib6_walk_continue(w);
read_unlock_bh(&table->tb6_lock);
if (res <= 0) {
--
Ben Greear <gree...@candelatech.com>
Candela Technologies Inc http://www.candelatech.com
