Module: xenomai-3
Branch: stable-3.0.x
Commit: 984d13432547d9cb9283162e3efd6b2224acb2a9
URL:
http://git.xenomai.org/?p=xenomai-3.git;a=commit;h=984d13432547d9cb9283162e3efd6b2224acb2a9
Author: Philippe Gerum <r...@xenomai.org>
Date: Thu Apr 26 11:03:50 2018 +0200
copperplate/heapobj-pshared: fix reservation in allocation bitmap
This is a severe bug which would cause an already reserved page range
to be returned twice in specific situations depending on the bitmap
contents at the time of the second allocation.
---
lib/copperplate/heapobj-pshared.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/lib/copperplate/heapobj-pshared.c
b/lib/copperplate/heapobj-pshared.c
index a3c5484..d4324df 100644
--- a/lib/copperplate/heapobj-pshared.c
+++ b/lib/copperplate/heapobj-pshared.c
@@ -289,8 +289,12 @@ static int reserve_page_range(uint32_t *bitmap, int
bitwords, int nrpages)
*/
for (n = 0, seq = 0; n < bitwords; n++) {
v = bitmap[n];
+ if (v == -1U) {
+ seq = 0;
+ continue;
+ }
b = 0;
- while (v != -1U) {
+ for (;;) {
r = __ctz(v);
if (r) {
seq += r;
@@ -316,8 +320,11 @@ static int reserve_page_range(uint32_t *bitmap, int
bitwords, int nrpages)
* keep searching for one which is at least
* nrpages-bit long.
*/
- if (v == -1U && b < 32)
- seq = 0;
+ if (v == -1U) {
+ if (b < 32)
+ seq = 0;
+ break;
+ }
}
}
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