rtos/linux: fix use of memory after it is freed

Discovered by clang static analyzer

Change-Id: I9f64a67f281b95562d8fd6e2ebb0ae3f79ae8039
Signed-off-by: Tomas Vanek <vanekt@fbl.cz>
Reviewed-on: http://openocd.zylin.com/5371
Tested-by: jenkins
Reviewed-by: Oleksij Rempel <linux@rempel-privat.de>

diff --git a/src/rtos/linux.c b/src/rtos/linux.c
index 74172b70a43c189b27d69cfe9e5e33f9c8cf72e0..9e59c41a52372843349ba238f83d7cdf3c2a88ad 100644 (file)
--- a/src/rtos/linux.c
+++ b/src/rtos/linux.c
@@ -621,17 +621,17 @@ struct threads *liste_del_task(struct threads *task_list, struct threads **t,
        struct threads *prev)
 {
        LOG_INFO("del task %" PRId64, (*t)->threadid);
-       prev->next = (*t)->next;
-
-       if (prev == task_list)
-               task_list = prev;
+       if (prev)
+               prev->next = (*t)->next;
+       else
+               task_list = (*t)->next;
 
        /*  free content of threads */
        if ((*t)->context)
                free((*t)->context);
 
        free(*t);
-       *t = prev;
+       *t = prev ? prev : task_list;
        return task_list;
 }
 
@@ -725,6 +725,7 @@ int linux_get_tasks(struct target *target, int context)
 
                /*  check that this thread is not one the current threads already
                 *  created */
+               uint32_t base_addr;
 #ifdef PID_CHECK
 
                if (!current_pid(linux_os, t->pid)) {
@@ -745,12 +746,13 @@ int linux_get_tasks(struct target *target, int context)
                                t->context =
                                        cpu_context_read(target, t->base_addr,
                                                &t->thread_info_addr);
+                       base_addr = next_task(target, t);
                } else {
                        /*LOG_INFO("thread %s is a current thread already created",t->name); */
+                       base_addr = next_task(target, t);
                        free(t);
                }
 
-               uint32_t base_addr = next_task(target, t);
                t = calloc(1, sizeof(struct threads));
                t->base_addr = base_addr;
        }
@@ -1178,7 +1180,7 @@ int linux_gdb_T_packet(struct connection *connection,
 
        if (linux_os->threads_needs_update == 0) {
                struct threads *temp = linux_os->thread_list;
-               struct threads *prev = linux_os->thread_list;
+               struct threads *prev = NULL;
 
                while (temp != NULL) {
                        if (temp->threadid == threadid) {