Date: Sat, 29 Aug 2015 21:27:42 +0200 From: Jilles Tjoelker <jilles@stack.nl> To: Konstantin Belousov <kostikbel@gmail.com> Cc: Michiel Boland <boland37@xs4all.nl>, Mark Martinec <Mark.Martinec+freebsd@ijs.si>, freebsd-stable@freebsd.org Subject: Re: Latest stable (r287104) bash leaves zombies on exit Message-ID: <20150829192742.GA48807@stack.nl> In-Reply-To: <20150829134130.GC2072@kib.kiev.ua> References: <63a84f64baf8768a551fc6464e8e9526@mailbox.ijs.si> <20150827162602.GJ2072@kib.kiev.ua> <55DF5C95.90502@xs4all.nl> <20150827201644.GO2072@kib.kiev.ua> <55DFFADB.2080003@xs4all.nl> <20150828100118.GR2072@kib.kiev.ua> <55E083CA.2050705@xs4all.nl> <20150828161847.GX2072@kib.kiev.ua> <20150829130138.GA41321@stack.nl> <20150829134130.GC2072@kib.kiev.ua>
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On Sat, Aug 29, 2015 at 04:41:30PM +0300, Konstantin Belousov wrote:
> On Sat, Aug 29, 2015 at 03:01:38PM +0200, Jilles Tjoelker wrote:
> > Looks good to me, except that I think a vforked child (in system() and
> > posix_spawn*()) should use the system calls and not libthr's wrappers.
> > This reduces the probability of weird things happening between vfork and
> > exec, and also avoids an unexpected error when
> > posix_spawnattr_setsigdefault()'s mask contains SIGTHR.
> Thank you for the review, I agree with the note about vfork. Updated
> patch is below. Also, I removed the PIC_PROLOGUE from the i386 setjmp,
> it has no use after the plt calls are removed.
> [snip]
> diff --git a/lib/libc/gen/posix_spawn.c b/lib/libc/gen/posix_spawn.c
> index e3124b2..673c760 100644
> --- a/lib/libc/gen/posix_spawn.c
> +++ b/lib/libc/gen/posix_spawn.c
> @@ -118,15 +118,18 @@ process_spawnattr(const posix_spawnattr_t sa)
> return (errno);
> }
>
> - /* Set signal masks/defaults */
> + /*
> + * Set signal masks/defaults.
> + * Use unwrapped syscall, libthr is in undefined state after vfork().
> + */
> if (sa->sa_flags & POSIX_SPAWN_SETSIGMASK) {
> - _sigprocmask(SIG_SETMASK, &sa->sa_sigmask, NULL);
> + __libc_sigprocmask(SIG_SETMASK, &sa->sa_sigmask, NULL);
> }
>
> if (sa->sa_flags & POSIX_SPAWN_SETSIGDEF) {
> for (i = 1; i <= _SIG_MAXSIG; i++) {
> if (sigismember(&sa->sa_sigdefault, i))
> - if (_sigaction(i, &sigact, NULL) != 0)
> + if (__libc_sigaction(i, &sigact, NULL) != 0)
> return (errno);
> }
> }
Hmm, the comments say direct syscalls are being used, but in fact
libthr's interposer is called. The change to system() does correctly use
__sys_sigprocmask().
--
Jilles Tjoelker
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