| Message ID | 20210109221834.3459768-1-willemdebruijn.kernel@gmail.com |
|---|---|
| Headers | show |
| Series | skb frag: kmap_atomic fixes | expand |
On Sat, Jan 09, 2021 at 05:18:34PM -0500, Willem de Bruijn wrote: > From: Willem de Bruijn <willemb@google.com> > > 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 <willemb@google.com> > Cc: Steffen Klassert <steffen.klassert@secunet.com> As this patchset goes through the net tree: Acked-by: Steffen Klassert <steffen.klassert@secunet.com> Thanks!
Hello: This series was applied to netdev/net.git (refs/heads/master): On Sat, 9 Jan 2021 17:18:31 -0500 you wrote: > From: Willem de Bruijn <willemb@google.com> > > skb frags may be backed by highmem and/or compound pages. Various > code calls kmap_atomic to safely access highmem pages. But this > needs additional care for compound pages. Fix a few issues: > > patch 1 expect kmap mappings with CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP > patch 2 fixes kmap_atomic + compound page support in skb_seq_read > patch 3 fixes kmap_atomic + compound page support in esp > > [...] Here is the summary with links: - [net,v2,1/3] net: support kmap_local forced debugging in skb_frag_foreach https://git.kernel.org/netdev/net/c/29766bcffad0 - [net,v2,2/3] net: compound page support in skb_seq_read https://git.kernel.org/netdev/net/c/97550f6fa592 - [net,v2,3/3] esp: avoid unneeded kmap_atomic call https://git.kernel.org/netdev/net/c/9bd6b629c39e You are awesome, thank you! -- Deet-doot-dot, I am a bot. https://korg.docs.kernel.org/patchwork/pwbot.html
From: Willem de Bruijn <willemb@google.com> skb frags may be backed by highmem and/or compound pages. Various code calls kmap_atomic to safely access highmem pages. But this needs additional care for compound pages. Fix a few issues: patch 1 expect kmap mappings with CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP patch 2 fixes kmap_atomic + compound page support in skb_seq_read patch 3 fixes kmap_atomic + compound page support in esp changes v1->v2 - in patch 2, increase frag_off size from u16 to u32 Willem de Bruijn (3): net: support kmap_local forced debugging in skb_frag_foreach net: compound page support in skb_seq_read esp: avoid unneeded kmap_atomic call include/linux/skbuff.h | 3 ++- net/core/skbuff.c | 28 +++++++++++++++++++++++----- net/ipv4/esp4.c | 7 +------ net/ipv6/esp6.c | 7 +------ 4 files changed, 27 insertions(+), 18 deletions(-)