From: Coly Li colyli@suse.de
commit cf83a17edeeb36195596d2dae060a7c381db35f1 upstream.
commit a10674bf2406 ("tcp: detecting the misuse of .sendpage for Slab objects") adds the checks for Slab pages, but the pages don't have page_count are still missing from the check.
Network layer's sendpage method is not designed to send page_count 0 pages neither, therefore both PageSlab() and page_count() should be both checked for the sending page. This is exactly what sendpage_ok() does.
This patch uses sendpage_ok() in do_tcp_sendpages() to detect misused .sendpage, to make the code more robust.
Fixes: a10674bf2406 ("tcp: detecting the misuse of .sendpage for Slab objects") Suggested-by: Eric Dumazet eric.dumazet@gmail.com Signed-off-by: Coly Li colyli@suse.de Cc: Vasily Averin vvs@virtuozzo.com Cc: David S. Miller davem@davemloft.net Cc: stable@vger.kernel.org Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- net/ipv4/tcp.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -971,7 +971,8 @@ ssize_t do_tcp_sendpages(struct sock *sk long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
if (IS_ENABLED(CONFIG_DEBUG_VM) && - WARN_ONCE(PageSlab(page), "page must not be a Slab one")) + WARN_ONCE(!sendpage_ok(page), + "page must not be a Slab one and have page_count > 0")) return -EINVAL;
/* Wait for a connection to finish. One exception is TCP Fast Open