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>
diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index e65b15d..f1bd3bb 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -1872,6 +1872,11 @@
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 @@
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 @@
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);