From af06737e7e3e536c5043adfc943e4b4600d19e36 Mon Sep 17 00:00:00 2001
From: Julian Oes <julian@oes.ch>
Date: Wed, 25 May 2016 21:50:23 +0200
Subject: [PATCH] sdlog2: fix Segfault on Eagle (#4638)
Since orb_exist doesn't work on the Snapdragon Linux side, we need to do
an additional orb_check after the orb_subscribe_multi, otherwise we copy
garbage.
The segfault was triggered by a count/length information about ESC
packets which lead to access outside the struct in the garbage case.
---
src/modules/sdlog2/sdlog2.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/src/modules/sdlog2/sdlog2.c b/src/modules/sdlog2/sdlog2.c
index 1c07400fd8..db783325a5 100644
--- a/src/modules/sdlog2/sdlog2.c
+++ b/src/modules/sdlog2/sdlog2.c
@@ -917,8 +917,13 @@ bool copy_if_updated_multi(orb_id_t topic, int multi_instance, int *handle, void
*handle = orb_subscribe_multi(topic, multi_instance);
/* copy first data */
if (*handle >= 0) {
- orb_copy(topic, *handle, buffer);
- updated = true;
+
+ /* but only if it has really been updated */
+ orb_check(*handle, &updated);
+
+ if (updated) {
+ orb_copy(topic, *handle, buffer);
+ }
}
}
} else {
--
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