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authorsantosh.shilimkar@oracle.com <santosh.shilimkar@oracle.com>2015-08-23 01:45:33 +0300
committerDavid S. Miller <davem@davemloft.net>2015-08-25 23:35:31 +0300
commitdfcec251d22bab947d10cf37e9ad67085cf7f097 (patch)
treedd9ef3f30a176b7aebe4dd24f9c73a1ff49939a9 /net/rds/send.c
parent1c3be624f40acd6f2bd0f22ade081ac2467e8617 (diff)
downloadlinux-dfcec251d22bab947d10cf37e9ad67085cf7f097.tar.xz
RDS: make sure rds_send_drop_to properly takes the m_rs_lock
rds_send_drop_to() is used during socket tear down to find all the messages on the socket and flush them . It can race with the acking code unless it takes the m_rs_lock on each and every message. This plugs a hole where we didn't take m_rs_lock on any message that didn't have the RDS_MSG_ON_CONN set. Taking m_rs_lock avoids double frees and other memory corruptions as the ack code trusts the message m_rs pointer on a socket that had actually been freed. We must take m_rs_lock to access m_rs. Because of lock nesting and rs access, we also need to acquire rs_lock. Reviewed-by: Ajaykumar Hotchandani <ajaykumar.hotchandani@oracle.com> Signed-off-by: Santosh Shilimkar <ssantosh@kernel.org> Signed-off-by: Santosh Shilimkar <santosh.shilimkar@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/rds/send.c')
-rw-r--r--net/rds/send.c16
1 files changed, 15 insertions, 1 deletions
diff --git a/net/rds/send.c b/net/rds/send.c
index faad1be61ab6..b40c2ea8e89a 100644
--- a/net/rds/send.c
+++ b/net/rds/send.c
@@ -778,8 +778,22 @@ void rds_send_drop_to(struct rds_sock *rs, struct sockaddr_in *dest)
while (!list_empty(&list)) {
rm = list_entry(list.next, struct rds_message, m_sock_item);
list_del_init(&rm->m_sock_item);
-
rds_message_wait(rm);
+
+ /* just in case the code above skipped this message
+ * because RDS_MSG_ON_CONN wasn't set, run it again here
+ * taking m_rs_lock is the only thing that keeps us
+ * from racing with ack processing.
+ */
+ spin_lock_irqsave(&rm->m_rs_lock, flags);
+
+ spin_lock(&rs->rs_lock);
+ __rds_send_complete(rs, rm, RDS_RDMA_CANCELED);
+ spin_unlock(&rs->rs_lock);
+
+ rm->m_rs = NULL;
+ spin_unlock_irqrestore(&rm->m_rs_lock, flags);
+
rds_message_put(rm);
}
}