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authorChunwei Chen <tuxoko@gmail.com>2014-04-23 12:35:09 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-06-07 13:25:40 -0700
commita757a4e215574f2c92fc990275fa5e02159771e1 (patch)
treede2d29cefe83ba059411276745a9f6145ee19d2f
parent534cc5572c710370d2bfe4e6b382950fd52c2c00 (diff)
downloadlinux-linaro-stable-a757a4e215574f2c92fc990275fa5e02159771e1.tar.gz
libceph: fix corruption when using page_count 0 page in rbd
commit 178eda29ca721842f2146378e73d43e0044c4166 upstream. It has been reported that using ZFSonLinux on rbd will result in memory corruption. The bug report can be found here: https://github.com/zfsonlinux/spl/issues/241 http://tracker.ceph.com/issues/7790 The reason is that ZFS will send pages with page_count 0 into rbd, which in turns send them to tcp_sendpage. However, tcp_sendpage cannot deal with page_count 0, as it will do get_page and put_page, and erroneously free the page. This type of issue has been noted before, and handled in iscsi, drbd, etc. So, rbd should also handle this. This fix address this issue by fall back to slower sendmsg when page_count 0 detected. Cc: Sage Weil <sage@inktank.com> Cc: Yehuda Sadeh <yehuda@inktank.com> Signed-off-by: Chunwei Chen <tuxoko@gmail.com> Reviewed-by: Ilya Dryomov <ilya.dryomov@inktank.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--net/ceph/messenger.c20
1 files changed, 19 insertions, 1 deletions
diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index eb0a46a49bd4..b9d7df175700 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -556,7 +556,7 @@ static int ceph_tcp_sendmsg(struct socket *sock, struct kvec *iov,
return r;
}
-static int ceph_tcp_sendpage(struct socket *sock, struct page *page,
+static int __ceph_tcp_sendpage(struct socket *sock, struct page *page,
int offset, size_t size, bool more)
{
int flags = MSG_DONTWAIT | MSG_NOSIGNAL | (more ? MSG_MORE : MSG_EOR);
@@ -569,6 +569,24 @@ static int ceph_tcp_sendpage(struct socket *sock, struct page *page,
return ret;
}
+static int ceph_tcp_sendpage(struct socket *sock, struct page *page,
+ int offset, size_t size, bool more)
+{
+ int ret;
+ struct kvec iov;
+
+ /* sendpage cannot properly handle pages with page_count == 0,
+ * we need to fallback to sendmsg if that's the case */
+ if (page_count(page) >= 1)
+ return __ceph_tcp_sendpage(sock, page, offset, size, more);
+
+ iov.iov_base = kmap(page) + offset;
+ iov.iov_len = size;
+ ret = ceph_tcp_sendmsg(sock, &iov, 1, size, more);
+ kunmap(page);
+
+ return ret;
+}
/*
* Shutdown/close the socket for the given connection.