Hi!
[ Upstream commit 0c85a7e87465f2d4cbc768e245f4f45b2f299b05 ]
In case of rs failure in rds_send_remove_from_sock(), the 'rm' resource is freed and later under spinlock, causing potential use-after-free. Set the free pointer to NULL to avoid undefined behavior.
This patch is crazy. Take a look at Message-ID: 20210419084953.GA28564@amd. Or just look at the patch :-).
Best regards, Pavel
+++ b/net/rds/message.c @@ -180,6 +180,7 @@ void rds_message_put(struct rds_message *rm) rds_message_purge(rm); kfree(rm);
rm = NULL;} EXPORT_SYMBOL_GPL(rds_message_put); diff --git a/net/rds/send.c b/net/rds/send.c index 985d0b7713ac..fe5264b9d4b3 100644 --- a/net/rds/send.c +++ b/net/rds/send.c @@ -665,7 +665,7 @@ static void rds_send_remove_from_sock(struct list_head *messages, int status) unlock_and_drop: spin_unlock_irqrestore(&rm->m_rs_lock, flags); rds_message_put(rm);
if (was_on_sock)
if (was_on_sock && rm) rds_message_put(rm);