lib: data-stack - start sentry checks immediately after the reserved buffer

Our sentries are written with byte-precision, no need to round up before
doing the checks.

Signed-off-by: Phil Carmody <phil@dovecot.fi>

diff --git a/src/lib/data-stack.c b/src/lib/data-stack.c
index 7a8cf7e87f277b5ef67d39f324185f1aa02263f2..53b95a4b240154544d23005c72309a3b966edb4a 100644 (file)
--- a/src/lib/data-stack.c
+++ b/src/lib/data-stack.c
@@ -101,12 +101,11 @@ static void data_stack_last_buffer_reset(bool preserve_data ATTR_UNUSED)
 {
        if (last_buffer_block != NULL) {
 #ifdef DEBUG
-               unsigned char *last_alloc_end, *p;
-               unsigned int i;
+               unsigned char *last_alloc_end, *p, *pend;
 
                last_alloc_end = data_stack_after_last_alloc(current_block);
-               p = last_alloc_end + MEM_ALIGN(sizeof(size_t)) + MEM_ALIGN(last_buffer_size);
-
+               p = last_alloc_end + MEM_ALIGN(sizeof(size_t)) + last_buffer_size;
+               pend = last_alloc_end + ALLOC_SIZE(last_buffer_size);
 #endif
                /* reset t_buffer_get() mark - not really needed but makes it
                   easier to notice if t_malloc()/t_push()/t_pop() is called
@@ -116,10 +115,9 @@ static void data_stack_last_buffer_reset(bool preserve_data ATTR_UNUSED)
                last_buffer_block = NULL;
 
 #ifdef DEBUG
-               for (i = 0; i < SENTRY_COUNT; i++) {
-                       if (p[i] != CLEAR_CHR)
+               while (p < pend)
+                       if (*p++ != CLEAR_CHR)
                                i_panic("t_buffer_get(): buffer overflow");
-               }
 
                if (!preserve_data) {
                        p = last_alloc_end;