Commit 4c3d795c authored Sep 12, 2018 by Tushar Dave Committed by Daniel Borkmann Sep 12, 2018

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: 015632bb ("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>

parent dd066823

net/core/filter.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -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);

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