From a4107026976f06c9a6ce8cc84a763564ee39d901 Mon Sep 17 00:00:00 2001
From: Sage Weil <sage@inktank.com>
Date: Mon, 30 Jul 2012 16:20:25 -0700
Subject: [PATCH] libceph: (re)initialize bio_iter on start of message receive
Previously, we were opportunistically initializing the bio_iter if it
appeared to be uninitialized in the middle of the read path. The problem
is that a sequence like:
- start reading message
- initialize bio_iter
- read half a message
- messenger fault, reconnect
- restart reading message
- ** bio_iter now non-NULL, not reinitialized **
- read past end of bio, crash
Instead, initialize the bio_iter unconditionally when we allocate/claim
the message for read.
Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Alex Elder <elder@inktank.com>
Reviewed-by: Yehuda Sadeh <yehuda@inktank.com>
---
net/ceph/messenger.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index e65b15d5d8b9..f1bd3bbb0c46 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -1872,6 +1872,11 @@ static int read_partial_message(struct ceph_connection *con)
else
con->in_msg_pos.page_pos = 0;
con->in_msg_pos.data_pos = 0;
+
+#ifdef CONFIG_BLOCK
+ if (m->bio)
+ init_bio_iter(m->bio, &m->bio_iter, &m->bio_seg);
+#endif
}
/* front */
@@ -1888,10 +1893,6 @@ static int read_partial_message(struct ceph_connection *con)
if (ret <= 0)
return ret;
}
-#ifdef CONFIG_BLOCK
- if (m->bio && !m->bio_iter)
- init_bio_iter(m->bio, &m->bio_iter, &m->bio_seg);
-#endif
/* (page) data */
while (con->in_msg_pos.data_pos < data_len) {
@@ -1902,7 +1903,7 @@ static int read_partial_message(struct ceph_connection *con)
return ret;
#ifdef CONFIG_BLOCK
} else if (m->bio) {
-
+ BUG_ON(!m->bio_iter);
ret = read_partial_message_bio(con,
&m->bio_iter, &m->bio_seg,
data_len, do_datacrc);
--
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