2020-01-13 18:21:38

by Felix Fietkau

[permalink] [raw]
Subject: [PATCH 5.5] cfg80211: fix page refcount issue in A-MSDU decap

The fragments attached to a skb can be part of a compound page. In that case,
page_ref_inc will increment the refcount for the wrong page. Fix this by
using get_page instead, which calls page_ref_inc on the compound head and
also checks for overflow.

Fixes: 2b67f944f88c ("cfg80211: reuse existing page fragments in A-MSDU rx")
Cc: [email protected]
Signed-off-by: Felix Fietkau <[email protected]>
---
net/wireless/util.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/wireless/util.c b/net/wireless/util.c
index 5b4ed5bbc542..8481e9ac33da 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -564,7 +564,7 @@ __frame_add_frag(struct sk_buff *skb, struct page *page,
struct skb_shared_info *sh = skb_shinfo(skb);
int page_offset;

- page_ref_inc(page);
+ get_page(page);
page_offset = ptr - page_address(page);
skb_add_rx_frag(skb, sh->nr_frags, page, page_offset, len, size);
}
--
2.24.0