From a5626cd14a7f27538033e1e110f9a827c0189526 Mon Sep 17 00:00:00 2001

From: Krzysztof Kotlenga <k.kotlenga@sims.pl>

Date: Thu, 24 Sep 2015 00:34:51 +0200

Subject: [PATCH] sd-event: fix prepare priority queue comparison function

Otherwise a disabled event source can get swapped with an enabled one

and cause a severe sd-event malfunction.

http://lists.freedesktop.org/archives/systemd-devel/2015-September/034356.html

Cherry-picked from: 8046c4576a68977a1089d2585866bfab8152661b

Resolves: #1266479

---

 src/libsystemd/sd-event/sd-event.c | 12 ++++++------

 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/libsystemd/sd-event/sd-event.c b/src/libsystemd/sd-event/sd-event.c

index c6350be9f..1f1e6fe91 100644

--- a/src/libsystemd/sd-event/sd-event.c

+++ b/src/libsystemd/sd-event/sd-event.c

@@ -231,6 +231,12 @@ static int prepare_prioq_compare(const void *a, const void *b) {

         assert(x->prepare);

         assert(y->prepare);

+        /* Enabled ones first */

+        if (x->enabled != SD_EVENT_OFF && y->enabled == SD_EVENT_OFF)

+                return -1;

+        if (x->enabled == SD_EVENT_OFF && y->enabled != SD_EVENT_OFF)

+                return 1;

+

         /* Move most recently prepared ones last, so that we can stop

          * preparing as soon as we hit one that has already been

          * prepared in the current iteration */

@@ -239,12 +245,6 @@ static int prepare_prioq_compare(const void *a, const void *b) {

         if (x->prepare_iteration > y->prepare_iteration)

                 return 1;

-        /* Enabled ones first */

-        if (x->enabled != SD_EVENT_OFF && y->enabled == SD_EVENT_OFF)

-                return -1;

-        if (x->enabled == SD_EVENT_OFF && y->enabled != SD_EVENT_OFF)

-                return 1;

-

         /* Lower priority values first */

         if (x->priority < y->priority)

                 return -1;