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authorEmily Shaffer <emilyshaffer@google.com>2019-09-30 22:03:55 (GMT)
committerJunio C Hamano <gitster@pobox.com>2019-10-02 05:56:54 (GMT)
commit65904b8b2b27c71a96d8a9c37c19bcc8f2d1380c (patch)
treebe344801a58957b8f19b2eb9de64f213da643065 /promisor-remote.c
parent8464f94aeb2a5eb1ba834460b695b171b95e3fc0 (diff)
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promisor-remote: skip move_to_tail when no-op
Previously, when promisor_remote_move_to_tail() is called for a promisor_remote which is currently the final element in promisors, a cycle is created in the promisors linked list. This cycle leads to a double free later on in promisor_remote_clear() when the final element of the promisors list is removed: promisors is set to promisors->next (a no-op, as promisors->next == promisors); the previous value of promisors is free()'d; then the new value of promisors (which is equal to the previous value of promisors) is also free()'d. This double-free error was unrecoverable for the user without removing the filter or re-cloning the repo and hoping to miss this edge case. Now, when promisor_remote_move_to_tail() would be a no-op, just do a no-op. In cases of promisor_remote_move_to_tail() where r is not already at the tail of the list, it works as before. Helped-by: Jeff King <peff@peff.net> Signed-off-by: Emily Shaffer <emilyshaffer@google.com> Acked-by: Christian Couder <christian.couder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'promisor-remote.c')
-rw-r--r--promisor-remote.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/promisor-remote.c b/promisor-remote.c
index 9bc296c..9bd5b79 100644
--- a/promisor-remote.c
+++ b/promisor-remote.c
@@ -89,6 +89,9 @@ static struct promisor_remote *promisor_remote_lookup(const char *remote_name,
static void promisor_remote_move_to_tail(struct promisor_remote *r,
struct promisor_remote *previous)
{
+ if (r->next == NULL)
+ return;
+
if (previous)
previous->next = r->next;
else