net: Fix oops when splicing skbs from a frag_list.
Lennert Buytenhek wrote:
> Since 4fb669948116d928ae44262ab7743732c574630d ("net: Optimize memory
> usage when splicing from sockets.") I'm seeing this oops (e.g. in
> 2.6.30-rc3) when splicing from a TCP socket to /dev/null on a driver
> (mv643xx_eth) that uses LRO in the skb mode (lro_receive_skb) rather
> than the frag mode:
My patch incorrectly assumed skb->sk was always valid, but for
"frag_listed" skbs we can only use skb->sk of their parent.
Reported-by: Lennert Buytenhek <buytenh@wantstofly.org>
Debugged-by: Lennert Buytenhek <buytenh@wantstofly.org>
Tested-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index ce6356c..f091a5a 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -1365,9 +1365,8 @@
static inline struct page *linear_to_page(struct page *page, unsigned int *len,
unsigned int *offset,
- struct sk_buff *skb)
+ struct sk_buff *skb, struct sock *sk)
{
- struct sock *sk = skb->sk;
struct page *p = sk->sk_sndmsg_page;
unsigned int off;
@@ -1405,13 +1404,14 @@
*/
static inline int spd_fill_page(struct splice_pipe_desc *spd, struct page *page,
unsigned int *len, unsigned int offset,
- struct sk_buff *skb, int linear)
+ struct sk_buff *skb, int linear,
+ struct sock *sk)
{
if (unlikely(spd->nr_pages == PIPE_BUFFERS))
return 1;
if (linear) {
- page = linear_to_page(page, len, &offset, skb);
+ page = linear_to_page(page, len, &offset, skb, sk);
if (!page)
return 1;
} else
@@ -1442,7 +1442,8 @@
static inline int __splice_segment(struct page *page, unsigned int poff,
unsigned int plen, unsigned int *off,
unsigned int *len, struct sk_buff *skb,
- struct splice_pipe_desc *spd, int linear)
+ struct splice_pipe_desc *spd, int linear,
+ struct sock *sk)
{
if (!*len)
return 1;
@@ -1465,7 +1466,7 @@
/* the linear region may spread across several pages */
flen = min_t(unsigned int, flen, PAGE_SIZE - poff);
- if (spd_fill_page(spd, page, &flen, poff, skb, linear))
+ if (spd_fill_page(spd, page, &flen, poff, skb, linear, sk))
return 1;
__segment_seek(&page, &poff, &plen, flen);
@@ -1481,8 +1482,8 @@
* pipe is full or if we already spliced the requested length.
*/
static int __skb_splice_bits(struct sk_buff *skb, unsigned int *offset,
- unsigned int *len,
- struct splice_pipe_desc *spd)
+ unsigned int *len, struct splice_pipe_desc *spd,
+ struct sock *sk)
{
int seg;
@@ -1492,7 +1493,7 @@
if (__splice_segment(virt_to_page(skb->data),
(unsigned long) skb->data & (PAGE_SIZE - 1),
skb_headlen(skb),
- offset, len, skb, spd, 1))
+ offset, len, skb, spd, 1, sk))
return 1;
/*
@@ -1502,7 +1503,7 @@
const skb_frag_t *f = &skb_shinfo(skb)->frags[seg];
if (__splice_segment(f->page, f->page_offset, f->size,
- offset, len, skb, spd, 0))
+ offset, len, skb, spd, 0, sk))
return 1;
}
@@ -1528,12 +1529,13 @@
.ops = &sock_pipe_buf_ops,
.spd_release = sock_spd_release,
};
+ struct sock *sk = skb->sk;
/*
* __skb_splice_bits() only fails if the output has no room left,
* so no point in going over the frag_list for the error case.
*/
- if (__skb_splice_bits(skb, &offset, &tlen, &spd))
+ if (__skb_splice_bits(skb, &offset, &tlen, &spd, sk))
goto done;
else if (!tlen)
goto done;
@@ -1545,14 +1547,13 @@
struct sk_buff *list = skb_shinfo(skb)->frag_list;
for (; list && tlen; list = list->next) {
- if (__skb_splice_bits(list, &offset, &tlen, &spd))
+ if (__skb_splice_bits(list, &offset, &tlen, &spd, sk))
break;
}
}
done:
if (spd.nr_pages) {
- struct sock *sk = skb->sk;
int ret;
/*