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bpf: use __GFP_COMP while allocating page 

Helper bpg_msg_pull_data() can allocate multiple pages while
linearizing multiple scatterlist elements into one shared page.
However, if the shared page has size > PAGE_SIZE, using
copy_page_to_iter() causes below warning.

e.g.
[ 6367.019832] WARNING: CPU: 2 PID: 7410 at lib/iov_iter.c:825
page_copy_sane.part.8+0x0/0x8

To avoid above warning, use __GFP_COMP while allocating multiple
contiguous pages.

Fixes: 015632bb30 ("bpf: sk_msg program helper bpf_sk_msg_pull_data")
Signed-off-by: Tushar Dave <tushar.n.dave@oracle.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Tushar Dave 2018-09-12 22:15:29 +02:00 committed by Daniel Borkmann
parent dd066823db
commit 4c3d795cb0
1 changed files with 2 additions and 1 deletions
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3
net/core/filter.c
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@ -2344,7 +2344,8 @@ BPF_CALL_4(bpf_msg_pull_data,
if (unlikely(bytes_sg_total > copy))
return -EINVAL;
page = alloc_pages(__GFP_NOWARN | GFP_ATOMIC, get_order(copy));
page = alloc_pages(__GFP_NOWARN | GFP_ATOMIC | __GFP_COMP,
get_order(copy));
if (unlikely(!page))
return -ENOMEM;
p = page_address(page);