diff mbox series

[v1,net,01/15] igmp: Fix data-races around sysctl_igmp_llm_reports.

Message ID 20220715171755.38497-2-kuniyu@amazon.com (mailing list archive)
State Accepted
Commit f6da2267e71106474fbc0943dc24928b9cb79119
Delegated to: Netdev Maintainers
Headers show
Series sysctl: Fix data-races around ipv4_net_table (Round 3). | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net, async
netdev/fixes_present success Fixes tag present in non-next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 6 this patch: 6
netdev/cc_maintainers warning 1 maintainers not CCed: yoshfuji@linux-ipv6.org
netdev/build_clang success Errors and warnings before: 6 this patch: 6
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 6 this patch: 6
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 69 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Kuniyuki Iwashima July 15, 2022, 5:17 p.m. UTC 
While reading sysctl_igmp_llm_reports, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its readers.

This test can be packed into a helper, so such changes will be in the
follow-up series after net is merged into net-next.

  if (ipv4_is_local_multicast(pmc->multiaddr) &&
      !READ_ONCE(net->ipv4.sysctl_igmp_llm_reports))

Fixes: df2cf4a78e48 ("IGMP: Inhibit reports for local multicast groups")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
---
CC: Philip Downey <pdowney@brocade.com>
---
 net/ipv4/igmp.c | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)
diff mbox series

Patch

diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c
index b65d074d9620..cf75fff170e4 100644
--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -467,7 +467,8 @@  static struct sk_buff *add_grec(struct sk_buff *skb, struct ip_mc_list *pmc,
 
 	if (pmc->multiaddr == IGMP_ALL_HOSTS)
 		return skb;
-	if (ipv4_is_local_multicast(pmc->multiaddr) && !net->ipv4.sysctl_igmp_llm_reports)
+	if (ipv4_is_local_multicast(pmc->multiaddr) &&
+	    !READ_ONCE(net->ipv4.sysctl_igmp_llm_reports))
 		return skb;
 
 	mtu = READ_ONCE(dev->mtu);
@@ -593,7 +594,7 @@  static int igmpv3_send_report(struct in_device *in_dev, struct ip_mc_list *pmc)
 			if (pmc->multiaddr == IGMP_ALL_HOSTS)
 				continue;
 			if (ipv4_is_local_multicast(pmc->multiaddr) &&
-			     !net->ipv4.sysctl_igmp_llm_reports)
+			    !READ_ONCE(net->ipv4.sysctl_igmp_llm_reports))
 				continue;
 			spin_lock_bh(&pmc->lock);
 			if (pmc->sfcount[MCAST_EXCLUDE])
@@ -736,7 +737,8 @@  static int igmp_send_report(struct in_device *in_dev, struct ip_mc_list *pmc,
 	if (type == IGMPV3_HOST_MEMBERSHIP_REPORT)
 		return igmpv3_send_report(in_dev, pmc);
 
-	if (ipv4_is_local_multicast(group) && !net->ipv4.sysctl_igmp_llm_reports)
+	if (ipv4_is_local_multicast(group) &&
+	    !READ_ONCE(net->ipv4.sysctl_igmp_llm_reports))
 		return 0;
 
 	if (type == IGMP_HOST_LEAVE_MESSAGE)
@@ -920,7 +922,8 @@  static bool igmp_heard_report(struct in_device *in_dev, __be32 group)
 
 	if (group == IGMP_ALL_HOSTS)
 		return false;
-	if (ipv4_is_local_multicast(group) && !net->ipv4.sysctl_igmp_llm_reports)
+	if (ipv4_is_local_multicast(group) &&
+	    !READ_ONCE(net->ipv4.sysctl_igmp_llm_reports))
 		return false;
 
 	rcu_read_lock();
@@ -1045,7 +1048,7 @@  static bool igmp_heard_query(struct in_device *in_dev, struct sk_buff *skb,
 		if (im->multiaddr == IGMP_ALL_HOSTS)
 			continue;
 		if (ipv4_is_local_multicast(im->multiaddr) &&
-		    !net->ipv4.sysctl_igmp_llm_reports)
+		    !READ_ONCE(net->ipv4.sysctl_igmp_llm_reports))
 			continue;
 		spin_lock_bh(&im->lock);
 		if (im->tm_running)
@@ -1296,7 +1299,8 @@  static void __igmp_group_dropped(struct ip_mc_list *im, gfp_t gfp)
 #ifdef CONFIG_IP_MULTICAST
 	if (im->multiaddr == IGMP_ALL_HOSTS)
 		return;
-	if (ipv4_is_local_multicast(im->multiaddr) && !net->ipv4.sysctl_igmp_llm_reports)
+	if (ipv4_is_local_multicast(im->multiaddr) &&
+	    !READ_ONCE(net->ipv4.sysctl_igmp_llm_reports))
 		return;
 
 	reporter = im->reporter;
@@ -1338,7 +1342,8 @@  static void igmp_group_added(struct ip_mc_list *im)
 #ifdef CONFIG_IP_MULTICAST
 	if (im->multiaddr == IGMP_ALL_HOSTS)
 		return;
-	if (ipv4_is_local_multicast(im->multiaddr) && !net->ipv4.sysctl_igmp_llm_reports)
+	if (ipv4_is_local_multicast(im->multiaddr) &&
+	    !READ_ONCE(net->ipv4.sysctl_igmp_llm_reports))
 		return;
 
 	if (in_dev->dead)
@@ -1642,7 +1647,7 @@  static void ip_mc_rejoin_groups(struct in_device *in_dev)
 		if (im->multiaddr == IGMP_ALL_HOSTS)
 			continue;
 		if (ipv4_is_local_multicast(im->multiaddr) &&
-		    !net->ipv4.sysctl_igmp_llm_reports)
+		    !READ_ONCE(net->ipv4.sysctl_igmp_llm_reports))
 			continue;
 
 		/* a failover is happening and switches