[PATCH AUTOSEL 5.10 18/38] bpf, net: Use DEV_STAT_INC()

[PATCH AUTOSEL 5.10 18/38] bpf, net: Use DEV_STAT_INC()

[Sasha Levin]

From: yunshui <jiangyunshui@kylinos.cn>

[ Upstream commit d9cbd8343b010016fcaabc361c37720dcafddcbe ]

syzbot/KCSAN reported that races happen when multiple CPUs updating
dev->stats.tx_error concurrently. Adopt SMP safe DEV_STATS_INC() to
update the dev->stats fields.

Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: yunshui <jiangyunshui@kylinos.cn>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20240523033520.4029314-1-jiangyunshui@kylinos.cn
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/core/filter.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/net/core/filter.c b/net/core/filter.c
index a3101cdfd47b9..001da7ccb7089 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -2266,12 +2266,12 @@ static int __bpf_redirect_neigh_v6(struct sk_buff *skb, struct net_device *dev,
 
 	err = bpf_out_neigh_v6(net, skb, dev, nh);
 	if (unlikely(net_xmit_eval(err)))
-		dev->stats.tx_errors++;
+		DEV_STATS_INC(dev, tx_errors);
 	else
 		ret = NET_XMIT_SUCCESS;
 	goto out_xmit;
 out_drop:
-	dev->stats.tx_errors++;
+	DEV_STATS_INC(dev, tx_errors);
 	kfree_skb(skb);
 out_xmit:
 	return ret;
@@ -2379,12 +2379,12 @@ static int __bpf_redirect_neigh_v4(struct sk_buff *skb, struct net_device *dev,
 
 	err = bpf_out_neigh_v4(net, skb, dev, nh);
 	if (unlikely(net_xmit_eval(err)))
-		dev->stats.tx_errors++;
+		DEV_STATS_INC(dev, tx_errors);
 	else
 		ret = NET_XMIT_SUCCESS;
 	goto out_xmit;
 out_drop:
-	dev->stats.tx_errors++;
+	DEV_STATS_INC(dev, tx_errors);
 	kfree_skb(skb);
 out_xmit:
 	return ret;
-- 
2.43.0

[PATCH AUTOSEL 5.10 37/38] libbpf: Add NULL checks to bpf_object__{prev_map,next_map}

[Sasha Levin]

From: Andreas Ziegler <ziegler.andreas@siemens.com>

[ Upstream commit cedc12c5b57f7efa6dbebfb2b140e8675f5a2616 ]

In the current state, an erroneous call to
bpf_object__find_map_by_name(NULL, ...) leads to a segmentation
fault through the following call chain:

  bpf_object__find_map_by_name(obj = NULL, ...)
  -> bpf_object__for_each_map(pos, obj = NULL)
  -> bpf_object__next_map((obj = NULL), NULL)
  -> return (obj = NULL)->maps

While calling bpf_object__find_map_by_name with obj = NULL is
obviously incorrect, this should not lead to a segmentation
fault but rather be handled gracefully.

As __bpf_map__iter already handles this situation correctly, we
can delegate the check for the regular case there and only add
a check in case the prev or next parameter is NULL.

Signed-off-by: Andreas Ziegler <ziegler.andreas@siemens.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20240703083436.505124-1-ziegler.andreas@siemens.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 tools/lib/bpf/libbpf.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 015ed8253f739..33cdcfe106344 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -9005,7 +9005,7 @@ __bpf_map__iter(const struct bpf_map *m, const struct bpf_object *obj, int i)
 struct bpf_map *
 bpf_map__next(const struct bpf_map *prev, const struct bpf_object *obj)
 {
-	if (prev == NULL)
+	if (prev == NULL && obj != NULL)
 		return obj->maps;
 
 	return __bpf_map__iter(prev, obj, 1);
@@ -9014,7 +9014,7 @@ bpf_map__next(const struct bpf_map *prev, const struct bpf_object *obj)
 struct bpf_map *
 bpf_map__prev(const struct bpf_map *next, const struct bpf_object *obj)
 {
-	if (next == NULL) {
+	if (next == NULL && obj != NULL) {
 		if (!obj->nr_maps)
 			return NULL;
 		return obj->maps + obj->nr_maps - 1;
-- 
2.43.0