This is a note to let you know that I've just added the patch titled
ipv4: Fix data-races around sysctl_fib_notify_on_flag_change.
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ipv4-fix-data-races-around-sysctl_fib_notify_on_flag.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 9aa6f4cced2c928ce2f202bef7c6a419240f5e60
Author: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
Date: Fri Jul 22 11:22:05 2022 -0700
ipv4: Fix data-races around sysctl_fib_notify_on_flag_change.
[ Upstream commit 96b9bd8c6d125490f9adfb57d387ef81a55a103e ]
While reading sysctl_fib_notify_on_flag_change, it can be changed
concurrently. Thus, we need to add READ_ONCE() to its readers.
Fixes: 680aea08e78c ("net: ipv4: Emit notification when fib hardware flags are changed")
Signed-off-by: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index a9cd9c2bd84e..19c6e7b93d3d 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -1037,6 +1037,7 @@ fib_find_matching_alias(struct net *net, const struct fib_rt_info *fri)
void fib_alias_hw_flags_set(struct net *net, const struct fib_rt_info *fri)
{
+ u8 fib_notify_on_flag_change;
struct fib_alias *fa_match;
struct sk_buff *skb;
int err;
@@ -1058,14 +1059,16 @@ void fib_alias_hw_flags_set(struct net *net, const struct fib_rt_info *fri)
WRITE_ONCE(fa_match->offload, fri->offload);
WRITE_ONCE(fa_match->trap, fri->trap);
+ fib_notify_on_flag_change = READ_ONCE(net->ipv4.sysctl_fib_notify_on_flag_change);
+
/* 2 means send notifications only if offload_failed was changed. */
- if (net->ipv4.sysctl_fib_notify_on_flag_change == 2 &&
+ if (fib_notify_on_flag_change == 2 &&
READ_ONCE(fa_match->offload_failed) == fri->offload_failed)
goto out;
WRITE_ONCE(fa_match->offload_failed, fri->offload_failed);
- if (!net->ipv4.sysctl_fib_notify_on_flag_change)
+ if (!fib_notify_on_flag_change)
goto out;
skb = nlmsg_new(fib_nlmsg_size(fa_match->fa_info), GFP_ATOMIC);
