Re: [LTP] openposix: timers/twoevtimers: Wait for both timer signals

[Li Wang <li.wang@linux.dev>]

Hi Jan,

linuxtestproject.agent@gmail.com wrote:

> Hi Jan,
> 
> On Fri, 9 Oct 2026, Jan Stancek via ltp wrote:
> > openposix: timers/twoevtimers: Wait for both timer signals
> 
> > +	PTS_WRITE_MSG("Caught abort signal\n");
> > +	PTS_WRITE_MSG("Caught alarm signal\n");
> > +		if (errno != EINTR) {
> > +			perror("nanosleep() did not return success\n");
> > +			return PTS_UNRESOLVED;
> > +		}
> 
> Medium: PTS_WRITE_MSG() calls write() without preserving errno. If the
> second signal arrives after nanosleep() sets EINTR but before the new
> errno check, a failed handler write (e.g. EAGAIN on a full nonblocking
> stdout pipe) causes a spurious unresolved result even when both timers
> fired. Save errno on entry and restore it before returning in both
> handlers.

The race condition pointed out by the AI seems plausible. Would it make
sense to save and restore errno in the signal handlers, like this:

static void handler_abrt(int signo PTS_ATTRIBUTE_UNUSED)
 {
+       int saved_errno = errno;
+
        PTS_WRITE_MSG("Caught abort signal\n");
        caughtabort++;
+
+       errno = saved_errno;
+
 }

 static void handler_alrm(int signo PTS_ATTRIBUTE_UNUSED)
 {
+       int saved_errno = errno;
+
        PTS_WRITE_MSG("Caught alarm signal\n");
        caughtalarm++;
+
+       errno = saved_errno;
 }

The rest part looks good to me.

-- 
Regards,
Li Wang

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