From: Coly Li <[email protected]>
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 <[email protected]>
Signed-off-by: Coly Li <[email protected]>
Cc: Vasily Averin <[email protected]>
Cc: David S. Miller <[email protected]>
Cc: [email protected]
Signed-off-by: David S. Miller <[email protected]>
(cherry-picked from ms cf83a17edeeb ("tcp: use sendpage_ok() to detect misused
.sendpage"))
Signed-off-by: Andrey Zhadchenko <[email protected]>
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 538d63c..f8dbf6f 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -962,7 +962,8 @@ ssize_t do_tcp_sendpages(struct sock *sk, struct page
*page, int offset,
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
--
1.8.3.1
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