Gary-Hobson commented on code in PR #13129:
URL: https://github.com/apache/nuttx/pull/13129#discussion_r1736362033
##########
sched/task/task_setup.c:
##########
@@ -170,6 +170,16 @@ static int nxtask_assign_pid(FAR struct tcb_s *tcb)
for (i = 0; i < g_npidhash / 2; i++)
{
+ if (g_pidhash[i] == NULL)
+ {
+ /* If the pid is not used, skip it.
+ * This may be triggered when a context switch occurs
+ * during mm_malloc and a thread is destroyed.
+ */
Review Comment:
Thread switching may occur during malloc, there are two situations that need
to be handled:
1. When switching, a new thread is created and g_pidhash is also expanded.
When returning, g_pidhash has changed and there may be empty elements in it. At
this time, accessing g_pidhash will access an illegal pointer
3. When switching, a thread exits, a member of g_pidhash is cleared, which
can also lead to illegal pointer access in subsequent iterations.
Since thread switching can only occur during the malloc/free process, the
other parts are protected by the critical section and thread switching will not
occur.
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