X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fcommon%2Fcompat%2Fcompat-poll.c;h=4893768a098543815207c90283eb9591d97a3a4a;hp=cff9f44b8e17c369a4b015866a825044bb43ef48;hb=53efb85a242809ed5ed21e9ab40effa696ecbc6f;hpb=d21b0d71990ac6ec4272c1f80f0ca544103628b3

diff --git a/src/common/compat/compat-poll.c b/src/common/compat/compat-poll.c
index cff9f44b8..4893768a0 100644
--- a/src/common/compat/compat-poll.c
+++ b/src/common/compat/compat-poll.c
@@ -23,6 +23,8 @@
 
 #include <common/defaults.h>
 #include <common/error.h>
+#include <common/macros.h>
+#include <common/utils.h>
 
 #include "poll.h"
 
@@ -40,11 +42,21 @@ static int resize_poll_event(struct compat_poll_event_array *array,
 
 	assert(array);
 
+	/* Refuse to resize the array more than the max size. */
+	if (new_size > poll_max_size) {
+		goto error;
+	}
+
 	ptr = realloc(array->events, new_size * sizeof(*ptr));
 	if (ptr == NULL) {
 		PERROR("realloc epoll add");
 		goto error;
 	}
+	if (new_size > array->alloc_size) {
+		/* Zero newly allocated memory */
+		memset(ptr + array->alloc_size, 0,
+			(new_size - array->alloc_size) * sizeof(*ptr));
+	}
 	array->events = ptr;
 	array->alloc_size = new_size;
 
@@ -163,7 +175,9 @@ int compat_poll_add(struct lttng_poll_event *events, int fd,
 	/* Check for a needed resize of the array. */
 	if (current->nb_fd > current->alloc_size) {
 		/* Expand it by a power of two of the current size. */
-		new_size = current->alloc_size << 1UL;
+		new_size = max_t(int,
+				1U << utils_get_count_order_u32(current->nb_fd),
+				current->alloc_size << 1UL);
 		ret = resize_poll_event(current, new_size);
 		if (ret < 0) {
 			goto error;
@@ -200,11 +214,6 @@ int compat_poll_del(struct lttng_poll_event *events, int fd)
 	/* Ease our life a bit. */
 	current = &events->current;
 
-	/* Safety check on size */
-	if (new_size > poll_max_size) {
-		new_size = poll_max_size;
-	}
-
 	/* Check if we need to shrink it down. */
 	if ((current->nb_fd << 1UL) <= current->alloc_size &&
 			current->nb_fd >= current->init_size) {
@@ -212,7 +221,9 @@ int compat_poll_del(struct lttng_poll_event *events, int fd)
 		 * Shrink if nb_fd multiplied by two is <= than the actual size and we
 		 * are above the initial size.
 		 */
-		new_size = current->alloc_size >> 1UL;
+		new_size = max_t(int,
+				utils_get_count_order_u32(current->nb_fd) >> 1U,
+				current->alloc_size >> 1U);
 		ret = resize_poll_event(current, new_size);
 		if (ret < 0) {
 			goto error;