diff mbox series

[net-next,03/13] ipv6: annotate data-races around cnf.mtu6

Message ID 20240226155055.1141336-4-edumazet@google.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series ipv6: lockless accesses to devconf | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1260 this patch: 1260
netdev/build_tools success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers success CCed 5 of 5 maintainers
netdev/build_clang success Errors and warnings before: 958 this patch: 958
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 1300 this patch: 1300
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 52 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-02-27--03-00 (tests: 1456)

Commit Message

Eric Dumazet Feb. 26, 2024, 3:50 p.m. UTC 
idev->cnf.mtu6 might be read locklessly, add appropriate READ_ONCE()
and WRITE_ONCE() annotations.

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 include/net/ip6_route.h | 2 +-
 net/ipv6/addrconf.c     | 4 ++--
 net/ipv6/ndisc.c        | 4 ++--
 net/ipv6/route.c        | 6 +++---
 4 files changed, 8 insertions(+), 8 deletions(-)
diff mbox series

Patch

diff --git a/include/net/ip6_route.h b/include/net/ip6_route.h
index 52a51c69aa9de2fe1e6d351997f5b3d94862521a..a30c6aa9e5cf3e442cd29e2d169ba0b0d46a1f46 100644
--- a/include/net/ip6_route.h
+++ b/include/net/ip6_route.h
@@ -332,7 +332,7 @@  static inline unsigned int ip6_dst_mtu_maybe_forward(const struct dst_entry *dst
 	rcu_read_lock();
 	idev = __in6_dev_get(dst->dev);
 	if (idev)
-		mtu = idev->cnf.mtu6;
+		mtu = READ_ONCE(idev->cnf.mtu6);
 	rcu_read_unlock();
 
 out:
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 0d7746b113cc65303b5c2ec223b3331c3598ded6..f1a346dbaceade70fb55fa98b33c47e6824298d3 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -3671,7 +3671,7 @@  static int addrconf_notify(struct notifier_block *this, unsigned long event,
 
 		if (idev) {
 			rt6_mtu_change(dev, dev->mtu);
-			idev->cnf.mtu6 = dev->mtu;
+			WRITE_ONCE(idev->cnf.mtu6, dev->mtu);
 			break;
 		}
 
@@ -3763,7 +3763,7 @@  static int addrconf_notify(struct notifier_block *this, unsigned long event,
 			if (idev->cnf.mtu6 != dev->mtu &&
 			    dev->mtu >= IPV6_MIN_MTU) {
 				rt6_mtu_change(dev, dev->mtu);
-				idev->cnf.mtu6 = dev->mtu;
+				WRITE_ONCE(idev->cnf.mtu6, dev->mtu);
 			}
 			WRITE_ONCE(idev->tstamp, jiffies);
 			inet6_ifinfo_notify(RTM_NEWLINK, idev);
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index 8523f0595b01899a9f6cf82809c1b4bcfc233202..e96d79cd34d27ca304c5f71b6db41b99d2dd8856 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -1578,8 +1578,8 @@  static enum skb_drop_reason ndisc_router_discovery(struct sk_buff *skb)
 
 		if (mtu < IPV6_MIN_MTU || mtu > skb->dev->mtu) {
 			ND_PRINTK(2, warn, "RA: invalid mtu: %d\n", mtu);
-		} else if (in6_dev->cnf.mtu6 != mtu) {
-			in6_dev->cnf.mtu6 = mtu;
+		} else if (READ_ONCE(in6_dev->cnf.mtu6) != mtu) {
+			WRITE_ONCE(in6_dev->cnf.mtu6, mtu);
 			fib6_metric_set(rt, RTAX_MTU, mtu);
 			rt6_mtu_change(skb->dev, mtu);
 		}
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 707d65bc9c0e5e9b2900063f0ac86c3c5e299088..66c685b0b6199fee3bc39768eab5a6fb831bd2f5 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1596,7 +1596,7 @@  static unsigned int fib6_mtu(const struct fib6_result *res)
 
 		rcu_read_lock();
 		idev = __in6_dev_get(dev);
-		mtu = idev->cnf.mtu6;
+		mtu = READ_ONCE(idev->cnf.mtu6);
 		rcu_read_unlock();
 	}
 
@@ -3249,8 +3249,8 @@  u32 ip6_mtu_from_fib6(const struct fib6_result *res,
 
 		mtu = IPV6_MIN_MTU;
 		idev = __in6_dev_get(dev);
-		if (idev && idev->cnf.mtu6 > mtu)
-			mtu = idev->cnf.mtu6;
+		if (idev)
+			mtu = max_t(u32, mtu, READ_ONCE(idev->cnf.mtu6));
 	}
 
 	mtu = min_t(unsigned int, mtu, IP6_MAX_MTU);