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| author | Herbert Xu <herbert@gondor.apana.org.au> | 2005-09-01 17:48:59 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2005-09-01 17:48:59 -0700 |
| commit | ef015786152adaff5a6a8bf0c8ea2f70cee8059d (patch) | |
| tree | 3042db7e451c61aefc60c1463bb6e307ca510638 | |
| parent | d80d99d643090c3cf2b1f9fb3fadd1256f7e384f (diff) | |
| download | linux-ef015786152adaff5a6a8bf0c8ea2f70cee8059d.tar.gz linux-ef015786152adaff5a6a8bf0c8ea2f70cee8059d.tar.bz2 linux-ef015786152adaff5a6a8bf0c8ea2f70cee8059d.zip | |
[TCP]: Fix sk_forward_alloc underflow in tcp_sendmsg
I've finally found a potential cause of the sk_forward_alloc underflows
that people have been reporting sporadically.
When tcp_sendmsg tacks on extra bits to an existing TCP_PAGE we don't
check sk_forward_alloc even though a large amount of time may have
elapsed since we allocated the page. In the mean time someone could've
come along and liberated packets and reclaimed sk_forward_alloc memory.
This patch makes tcp_sendmsg check sk_forward_alloc every time as we
do in do_tcp_sendpages.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | include/net/sock.h | 5 | ||||
| -rw-r--r-- | net/ipv4/tcp.c | 14 |
2 files changed, 11 insertions, 8 deletions
diff --git a/include/net/sock.h b/include/net/sock.h index e51e626e9af1..cf628261da52 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -1232,9 +1232,8 @@ static inline struct page *sk_stream_alloc_page(struct sock *sk) { struct page *page = NULL; - if (sk_stream_wmem_schedule(sk, PAGE_SIZE)) - page = alloc_pages(sk->sk_allocation, 0); - else { + page = alloc_pages(sk->sk_allocation, 0); + if (!page) { sk->sk_prot->enter_memory_pressure(); sk_stream_moderate_sndbuf(sk); } diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 854f6d0c4bb3..cbcc9fc47783 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -769,19 +769,23 @@ new_segment: if (off == PAGE_SIZE) { put_page(page); TCP_PAGE(sk) = page = NULL; + TCP_OFF(sk) = off = 0; } - } + } else + BUG_ON(off); + + if (copy > PAGE_SIZE - off) + copy = PAGE_SIZE - off; + + if (!sk_stream_wmem_schedule(sk, copy)) + goto wait_for_memory; if (!page) { /* Allocate new cache page. */ if (!(page = sk_stream_alloc_page(sk))) goto wait_for_memory; - off = 0; } - if (copy > PAGE_SIZE - off) - copy = PAGE_SIZE - off; - /* Time to copy data. We are close to * the end! */ err = skb_copy_to_page(sk, from, skb, page, |