diff mbox series

[v1,net,04/15] igmp: Fix data-races around sysctl_igmp_qrv.

Message ID 20220715171755.38497-5-kuniyu@amazon.com (mailing list archive)
State Accepted
Commit 8ebcc62c738f68688ee7c6fec2efe5bc6d3d7e60
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: 7 this patch: 7
netdev/cc_maintainers fail 1 blamed authors not CCed: fbl@redhat.com; 3 maintainers not CCed: yoshfuji@linux-ipv6.org fbl@redhat.com ap420073@gmail.com
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: 7 this patch: 7
netdev/checkpatch warning WARNING: line length of 82 exceeds 80 columns WARNING: line length of 85 exceeds 80 columns WARNING: line length of 86 exceeds 80 columns WARNING: line length of 97 exceeds 80 columns
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_qrv, 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.

  qrv ?: READ_ONCE(net->ipv4.sysctl_igmp_qrv);

Fixes: a9fe8e29945d ("ipv4: implement igmp_qrv sysctl to tune igmp robustness variable")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
---
CC: Hannes Frederic Sowa <hannes@stressinduktion.org>
---
 drivers/net/amt.c |  4 ++--
 net/ipv4/igmp.c   | 24 +++++++++++++-----------
 2 files changed, 15 insertions(+), 13 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/amt.c b/drivers/net/amt.c
index be2719a3ba70..89563d1b2a3b 100644
--- a/drivers/net/amt.c
+++ b/drivers/net/amt.c
@@ -563,7 +563,7 @@  static struct sk_buff *amt_build_igmp_gq(struct amt_dev *amt)
 	ihv3->nsrcs	= 0;
 	ihv3->resv	= 0;
 	ihv3->suppress	= false;
-	ihv3->qrv	= amt->net->ipv4.sysctl_igmp_qrv;
+	ihv3->qrv	= READ_ONCE(amt->net->ipv4.sysctl_igmp_qrv);
 	ihv3->csum	= 0;
 	csum		= &ihv3->csum;
 	csum_start	= (void *)ihv3;
@@ -3095,7 +3095,7 @@  static int amt_newlink(struct net *net, struct net_device *dev,
 		goto err;
 	}
 	if (amt->mode == AMT_MODE_RELAY) {
-		amt->qrv = amt->net->ipv4.sysctl_igmp_qrv;
+		amt->qrv = READ_ONCE(amt->net->ipv4.sysctl_igmp_qrv);
 		amt->qri = 10;
 		dev->needed_headroom = amt->stream_dev->needed_headroom +
 				       AMT_RELAY_HLEN;
diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c
index cd7839db34da..e3ab0cb61624 100644
--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -827,7 +827,7 @@  static void igmp_ifc_event(struct in_device *in_dev)
 	struct net *net = dev_net(in_dev->dev);
 	if (IGMP_V1_SEEN(in_dev) || IGMP_V2_SEEN(in_dev))
 		return;
-	WRITE_ONCE(in_dev->mr_ifc_count, in_dev->mr_qrv ?: net->ipv4.sysctl_igmp_qrv);
+	WRITE_ONCE(in_dev->mr_ifc_count, in_dev->mr_qrv ?: READ_ONCE(net->ipv4.sysctl_igmp_qrv));
 	igmp_ifc_start_timer(in_dev, 1);
 }
 
@@ -1009,7 +1009,7 @@  static bool igmp_heard_query(struct in_device *in_dev, struct sk_buff *skb,
 		 * received value was zero, use the default or statically
 		 * configured value.
 		 */
-		in_dev->mr_qrv = ih3->qrv ?: net->ipv4.sysctl_igmp_qrv;
+		in_dev->mr_qrv = ih3->qrv ?: READ_ONCE(net->ipv4.sysctl_igmp_qrv);
 		in_dev->mr_qi = IGMPV3_QQIC(ih3->qqic)*HZ ?: IGMP_QUERY_INTERVAL;
 
 		/* RFC3376, 8.3. Query Response Interval:
@@ -1189,7 +1189,7 @@  static void igmpv3_add_delrec(struct in_device *in_dev, struct ip_mc_list *im,
 	pmc->interface = im->interface;
 	in_dev_hold(in_dev);
 	pmc->multiaddr = im->multiaddr;
-	pmc->crcount = in_dev->mr_qrv ?: net->ipv4.sysctl_igmp_qrv;
+	pmc->crcount = in_dev->mr_qrv ?: READ_ONCE(net->ipv4.sysctl_igmp_qrv);
 	pmc->sfmode = im->sfmode;
 	if (pmc->sfmode == MCAST_INCLUDE) {
 		struct ip_sf_list *psf;
@@ -1240,9 +1240,11 @@  static void igmpv3_del_delrec(struct in_device *in_dev, struct ip_mc_list *im)
 			swap(im->tomb, pmc->tomb);
 			swap(im->sources, pmc->sources);
 			for (psf = im->sources; psf; psf = psf->sf_next)
-				psf->sf_crcount = in_dev->mr_qrv ?: net->ipv4.sysctl_igmp_qrv;
+				psf->sf_crcount = in_dev->mr_qrv ?:
+					READ_ONCE(net->ipv4.sysctl_igmp_qrv);
 		} else {
-			im->crcount = in_dev->mr_qrv ?: net->ipv4.sysctl_igmp_qrv;
+			im->crcount = in_dev->mr_qrv ?:
+				READ_ONCE(net->ipv4.sysctl_igmp_qrv);
 		}
 		in_dev_put(pmc->interface);
 		kfree_pmc(pmc);
@@ -1349,7 +1351,7 @@  static void igmp_group_added(struct ip_mc_list *im)
 	if (in_dev->dead)
 		return;
 
-	im->unsolicit_count = net->ipv4.sysctl_igmp_qrv;
+	im->unsolicit_count = READ_ONCE(net->ipv4.sysctl_igmp_qrv);
 	if (IGMP_V1_SEEN(in_dev) || IGMP_V2_SEEN(in_dev)) {
 		spin_lock_bh(&im->lock);
 		igmp_start_timer(im, IGMP_INITIAL_REPORT_DELAY);
@@ -1363,7 +1365,7 @@  static void igmp_group_added(struct ip_mc_list *im)
 	 * IN() to IN(A).
 	 */
 	if (im->sfmode == MCAST_EXCLUDE)
-		im->crcount = in_dev->mr_qrv ?: net->ipv4.sysctl_igmp_qrv;
+		im->crcount = in_dev->mr_qrv ?: READ_ONCE(net->ipv4.sysctl_igmp_qrv);
 
 	igmp_ifc_event(in_dev);
 #endif
@@ -1754,7 +1756,7 @@  static void ip_mc_reset(struct in_device *in_dev)
 
 	in_dev->mr_qi = IGMP_QUERY_INTERVAL;
 	in_dev->mr_qri = IGMP_QUERY_RESPONSE_INTERVAL;
-	in_dev->mr_qrv = net->ipv4.sysctl_igmp_qrv;
+	in_dev->mr_qrv = READ_ONCE(net->ipv4.sysctl_igmp_qrv);
 }
 #else
 static void ip_mc_reset(struct in_device *in_dev)
@@ -1888,7 +1890,7 @@  static int ip_mc_del1_src(struct ip_mc_list *pmc, int sfmode,
 #ifdef CONFIG_IP_MULTICAST
 		if (psf->sf_oldin &&
 		    !IGMP_V1_SEEN(in_dev) && !IGMP_V2_SEEN(in_dev)) {
-			psf->sf_crcount = in_dev->mr_qrv ?: net->ipv4.sysctl_igmp_qrv;
+			psf->sf_crcount = in_dev->mr_qrv ?: READ_ONCE(net->ipv4.sysctl_igmp_qrv);
 			psf->sf_next = pmc->tomb;
 			pmc->tomb = psf;
 			rv = 1;
@@ -1952,7 +1954,7 @@  static int ip_mc_del_src(struct in_device *in_dev, __be32 *pmca, int sfmode,
 		/* filter mode change */
 		pmc->sfmode = MCAST_INCLUDE;
 #ifdef CONFIG_IP_MULTICAST
-		pmc->crcount = in_dev->mr_qrv ?: net->ipv4.sysctl_igmp_qrv;
+		pmc->crcount = in_dev->mr_qrv ?: READ_ONCE(net->ipv4.sysctl_igmp_qrv);
 		WRITE_ONCE(in_dev->mr_ifc_count, pmc->crcount);
 		for (psf = pmc->sources; psf; psf = psf->sf_next)
 			psf->sf_crcount = 0;
@@ -2131,7 +2133,7 @@  static int ip_mc_add_src(struct in_device *in_dev, __be32 *pmca, int sfmode,
 #ifdef CONFIG_IP_MULTICAST
 		/* else no filters; keep old mode for reports */
 
-		pmc->crcount = in_dev->mr_qrv ?: net->ipv4.sysctl_igmp_qrv;
+		pmc->crcount = in_dev->mr_qrv ?: READ_ONCE(net->ipv4.sysctl_igmp_qrv);
 		WRITE_ONCE(in_dev->mr_ifc_count, pmc->crcount);
 		for (psf = pmc->sources; psf; psf = psf->sf_next)
 			psf->sf_crcount = 0;