pussuw opened a new pull request, #12434:
URL: https://github.com/apache/nuttx/pull/12434
## Summary
waitpid() cannot be used in kernel mode unless SCHED_HAVE_PARENT is selected
-> just automatically take it into use if waitpid() is needed.
Why? Because without SCHED_HAVE_PARENT waitpid() works in a non-standard
way, meaning it does not use SIGCHLD to wake the parent, as it should.
Also, returning the child status via stat_loc corrupts memory as stat_loc
points to the parent's address environment:
pid_t nxsched_waitpid(pid_t pid, int *stat_loc, int options)
{
...
group->tg_statloc = stat_loc;
...
}
And later when the status is returned, the child writes to tg_statloc, which
points to the parent's address environment -> random memory corruption:
static inline void nxtask_exitwakeup(FAR struct tcb_s *tcb, int status)
{
...
if (group->tg_statloc != NULL)
{
*group->tg_statloc = status << 8;
}
...
}
## Impact
Fix a bug in kernel mode
## Testing
ostest
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