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net: Fix oops when splicing skbs from a frag_list. 

Lennert Buytenhek wrote:
> Since 4fb6699481 ("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>
This commit is contained in:
Jarek Poplawski 2009-04-30 05:41:19 -07:00 committed by David S. Miller
parent 93af7aca44
commit 7a67e56fd3
1 changed files with 14 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

27
net/core/skbuff.c
View File

@ -1365,9 +1365,8 @@ static void sock_spd_release(struct splice_pipe_desc *spd, unsigned int i)
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 @@ new_page:
*/
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 void __segment_seek(struct page **page, unsigned int *poff,
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 @@ static inline int __splice_segment(struct page *page, unsigned int poff,
/* 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 @@ static inline int __splice_segment(struct page *page, unsigned int poff,
* 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 @@ static int __skb_splice_bits(struct sk_buff *skb, unsigned int *offset,
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 @@ static int __skb_splice_bits(struct sk_buff *skb, unsigned int *offset,
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 @@ int skb_splice_bits(struct sk_buff *skb, unsigned int offset,
.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 @@ int skb_splice_bits(struct sk_buff *skb, unsigned int offset,
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;
/*