diff mbox series

[net,1/5] ipv6: ioam: block BH from ioam6_output()

Message ID 20240531132636.2637995-2-edumazet@google.com (mailing list archive)
State Accepted
Commit 2fe40483ec257de2a0d819ef88e3e76c7e261319
Delegated to: Netdev Maintainers
Headers show
Series dst_cache: fix possible races | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 902 this patch: 902
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers warning 1 maintainers not CCed: dsahern@kernel.org
netdev/build_clang success Errors and warnings before: 906 this patch: 906
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 Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 906 this patch: 906
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 22 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-2024-06-03--15-00 (tests: 1041)

Commit Message

Eric Dumazet May 31, 2024, 1:26 p.m. UTC 
As explained in commit 1378817486d6 ("tipc: block BH
before using dst_cache"), net/core/dst_cache.c
helpers need to be called with BH disabled.

Disabling preemption in ioam6_output() is not good enough,
because ioam6_output() is called from process context,
lwtunnel_output() only uses rcu_read_lock().

We might be interrupted by a softirq, re-enter ioam6_output()
and corrupt dst_cache data structures.

Fix the race by using local_bh_disable() instead of
preempt_disable().

Fixes: 8cb3bf8bff3c ("ipv6: ioam: Add support for the ip6ip6 encapsulation")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Justin Iurman <justin.iurman@uliege.be>
---
 net/ipv6/ioam6_iptunnel.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)
diff mbox series

Patch

diff --git a/net/ipv6/ioam6_iptunnel.c b/net/ipv6/ioam6_iptunnel.c
index 7563f8c6aa87cf9f7841ee78dcea2a16f60ac344..bf7120ecea1ebe834e70073710be0c1692d7ad1d 100644
--- a/net/ipv6/ioam6_iptunnel.c
+++ b/net/ipv6/ioam6_iptunnel.c
@@ -351,9 +351,9 @@  static int ioam6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
 		goto drop;
 
 	if (!ipv6_addr_equal(&orig_daddr, &ipv6_hdr(skb)->daddr)) {
-		preempt_disable();
+		local_bh_disable();
 		dst = dst_cache_get(&ilwt->cache);
-		preempt_enable();
+		local_bh_enable();
 
 		if (unlikely(!dst)) {
 			struct ipv6hdr *hdr = ipv6_hdr(skb);
@@ -373,9 +373,9 @@  static int ioam6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
 				goto drop;
 			}
 
-			preempt_disable();
+			local_bh_disable();
 			dst_cache_set_ip6(&ilwt->cache, dst, &fl6.saddr);
-			preempt_enable();
+			local_bh_enable();
 		}
 
 		skb_dst_drop(skb);