On Wed, May 17, 2017 at 07:50:31PM +0200, Florian Weimer wrote:
> On 05/17/2017 07:36 PM, Markus Trippelsdorf wrote:
> > Since:
> > commit cfafcd117da0216520568c195cb2f6cd1980c4bb
> > Author: Peter Zijlstra <pet...@infradead.org>
> > Date: Wed Mar 22 11:35:58 2017 +0100
> >
> > futex: Rework futex_lock_pi() to use rt_mutex_*_proxy_lock()
> >
> > glibc's nptl/tst-robustpi8 testcase fails:
> >
> > glibc-build % ./nptl/tst-robustpi8
> > tst-robustpi8: ../nptl/pthread_mutex_lock.c:424: __pthread_mutex_lock_full:
> > Assertion `INTERNAL_SYSCALL_ERRNO (e, __err) != ESRCH || !robust' failed.
> >
> > pthread_mutex_lock.c:
> > 415 if (INTERNAL_SYSCALL_ERROR_P (e, __err)
> > 416 && (INTERNAL_SYSCALL_ERRNO (e, __err) == ESRCH
> > 417 || INTERNAL_SYSCALL_ERRNO (e, __err) == EDEADLK))
> > 418 {
> > 419 assert (INTERNAL_SYSCALL_ERRNO (e, __err) != EDEADLK
> > 420 || (kind != PTHREAD_MUTEX_ERRORCHECK_NP
> > 421 && kind != PTHREAD_MUTEX_RECURSIVE_NP));
> > 422 /* ESRCH can happen only for non-robust PI mutexes where
> > 423 the owner of the lock died. */
> > 424 assert (INTERNAL_SYSCALL_ERRNO (e, __err) != ESRCH ||
> > !robust);
> >
> > During bisection the commit above hangs the machine when I run the
> > testcase.
> >
> > See: https://sourceware.org/bugzilla/show_bug.cgi?id=21487
>
> Markus, could you confirm that it is chocking on the EAGAIN failure? Or
> is it something else?
>
> What is userspace supposed to do with the error code?
IIRC that -EAGAIN should not get to userspace. The kernel should retry
the lock operation. I'll go stare at it.
