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From: Coly Li <>
Cc:, Coly Li <>,
	Eric Dumazet <>,
	Vasily Averin <>,
	"David S . Miller" <>,
Subject: [PATCH v6 3/6] tcp: use sendpage_ok() to detect misused .sendpage
Date: Tue, 18 Aug 2020 20:47:33 +0800	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

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()

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 <>
Signed-off-by: Coly Li <>
Cc: Vasily Averin <>
Cc: David S. Miller <>
 net/ipv4/tcp.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 31f3b858db81..d96c7549895a 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -970,7 +970,8 @@ ssize_t do_tcp_sendpages(struct sock *sk, struct page *page, int offset,
 	long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
-	    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

  parent reply	other threads:[~2020-08-18 12:48 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-18 12:47 [PATCH v6 0/6] Introduce sendpage_ok() to detect misused sendpage in network related drivers Coly Li
2020-08-18 12:47 ` [PATCH v6 1/6] net: introduce helper sendpage_ok() in include/linux/net.h Coly Li
2020-08-18 12:47 ` [PATCH v6 2/6] nvme-tcp: check page by sendpage_ok() before calling kernel_sendpage() Coly Li
2020-08-18 12:47 ` Coly Li [this message]
2020-08-18 12:47 ` [PATCH v6 4/6] drbd: code cleanup by using sendpage_ok() to check page for kernel_sendpage() Coly Li
2020-08-18 12:47 ` [PATCH v6 5/6] scsi: libiscsi: use sendpage_ok() in iscsi_tcp_segment_map() Coly Li
2020-08-18 12:47 ` [PATCH v6 6/6] libceph: use sendpage_ok() in ceph_tcp_sendpage() Coly Li

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