Commit 7233890d8540a908c480949878fa482f9c9ce6b7
2012-04-29T10:03:01
Protect the freeing of current_hash under mutex_lock to prevent racing on it when set_curblock is hit concurrently.
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diff --git a/cgminer.c b/cgminer.c
index 37af3b9..e330935 100644
--- a/cgminer.c
+++ b/cgminer.c
@@ -161,7 +161,9 @@ static pthread_mutex_t *stgd_lock;
#ifdef HAVE_CURSES
static pthread_mutex_t curses_lock;
#endif
+static pthread_mutex_t ch_lock;
static pthread_rwlock_t blk_lock;
+
pthread_rwlock_t netacc_lock;
double total_mhashes_done;
@@ -2419,23 +2421,25 @@ static void restart_threads(void)
static void set_curblock(char *hexstr, unsigned char *hash)
{
unsigned char hash_swap[32];
- char *old_hash = NULL;
struct timeval tv_now;
+ char *old_hash;
- /* Don't free current_hash directly to avoid dereferencing it when
- * we might be accessing its data elsewhere */
- if (current_hash)
- old_hash = current_hash;
strcpy(current_block, hexstr);
gettimeofday(&tv_now, NULL);
get_timestamp(blocktime, &tv_now);
swap256(hash_swap, hash);
+
+ /* Don't free current_hash directly to avoid dereferencing when read
+ * elsewhere */
+ mutex_lock(&ch_lock);
+ old_hash = current_hash;
current_hash = bin2hex(hash_swap, 16);
+ free(old_hash);
+ mutex_unlock(&ch_lock);
+
if (unlikely(!current_hash))
quit (1, "set_curblock OOM");
applog(LOG_INFO, "New block: %s...", current_hash);
- if (old_hash)
- free(old_hash);
}
/* Search to see if this string is from a block that has been seen before */
@@ -4706,6 +4710,7 @@ int main(int argc, char *argv[])
#endif
mutex_init(&control_lock);
mutex_init(&sharelog_lock);
+ mutex_init(&ch_lock);
rwlock_init(&blk_lock);
rwlock_init(&netacc_lock);