From 814e0477621127badcfbd50c6f5139e9203a2295 Mon Sep 17 00:00:00 2001 From: Willem de Bruijn Date: Sat, 9 Jan 2021 17:18:34 -0500 Subject: esp: avoid unneeded kmap_atomic call [ Upstream commit 9bd6b629c39e3fa9e14243a6d8820492be1a5b2e ] esp(6)_output_head uses skb_page_frag_refill to allocate a buffer for the esp trailer. It accesses the page with kmap_atomic to handle highmem. But skb_page_frag_refill can return compound pages, of which kmap_atomic only maps the first underlying page. skb_page_frag_refill does not return highmem, because flag __GFP_HIGHMEM is not set. ESP uses it in the same manner as TCP. That also does not call kmap_atomic, but directly uses page_address, in skb_copy_to_page_nocache. Do the same for ESP. This issue has become easier to trigger with recent kmap local debugging feature CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP. Fixes: cac2661c53f3 ("esp4: Avoid skb_cow_data whenever possible") Fixes: 03e2a30f6a27 ("esp6: Avoid skb_cow_data whenever possible") Signed-off-by: Willem de Bruijn Acked-by: Steffen Klassert Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/ipv6/esp6.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) (limited to 'net/ipv6') diff --git a/net/ipv6/esp6.c b/net/ipv6/esp6.c index a3b403ba8f8f..7a739f16d82b 100644 --- a/net/ipv6/esp6.c +++ b/net/ipv6/esp6.c @@ -226,7 +226,6 @@ static void esp_output_fill_trailer(u8 *tail, int tfclen, int plen, __u8 proto) int esp6_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) { u8 *tail; - u8 *vaddr; int nfrags; struct page *page; struct sk_buff *trailer; @@ -259,14 +258,10 @@ int esp6_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info page = pfrag->page; get_page(page); - vaddr = kmap_atomic(page); - - tail = vaddr + pfrag->offset; + tail = page_address(page) + pfrag->offset; esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); - kunmap_atomic(vaddr); - nfrags = skb_shinfo(skb)->nr_frags; __skb_fill_page_desc(skb, nfrags, page, pfrag->offset, -- cgit v1.2.3