On Wed, Aug 20, 2014 at 04:41:05PM +0200, Roger Pau Monn?? wrote: > On 27/04/14 07:28, Konstantin Belousov wrote: > > Author: kib > > Date: Sun Apr 27 05:28:14 2014 > > New Revision: 265003 > > URL: http://svnweb.freebsd.org/changeset/base/265003 > > > > Log: > > Fix order of libthr and libc in the global dso list for sshd, by > > explicitely linking main binary with -lpthread. Before, libthr > > appeared in the list due to dependency of one of the kerberos libs. > > Due to the change in ld(1) behaviour of not copying NEEDED entries > > from direct dependencies into the link results, the order becomes > > reversed. > > > > The libthr must appear before libc to properly interpose libc symbols > > and provide working rtld locks implementation. The symptom was sshd > > hanging on rtld bind lock during nested symbol binding from a signal > > handler. > > > > Approved by: des (openssh maintainer) > > Sponsored by: The FreeBSD Foundation > > MFC after: 1 week > > > > Modified: > > head/secure/usr.sbin/sshd/Makefile > > > > Modified: head/secure/usr.sbin/sshd/Makefile > > ============================================================================== > > --- head/secure/usr.sbin/sshd/Makefile Sun Apr 27 05:19:01 2014 > > (r265002) > > +++ head/secure/usr.sbin/sshd/Makefile Sun Apr 27 05:28:14 2014 > > (r265003) > > @@ -57,6 +57,16 @@ CFLAGS+= -DNONE_CIPHER_ENABLED > > DPADD+= ${LIBCRYPT} ${LIBCRYPTO} ${LIBZ} > > LDADD+= -lcrypt -lcrypto -lz > > > > +# Fix the order of NEEDED entries for libthr and libc. The libthr > > +# needs to interpose libc symbols, leaving the libthr loading as > > +# dependency of krb causes reversed order and broken interposing. Put > > +# the threading library last on the linker command line, just before > > +# the -lc added by a compiler driver. > > +.if ${MK_KERBEROS_SUPPORT} != "no" > > +DPADD+= ${LIBPTHREAD} > > +LDADD+= -lpthread > > +.endif > > + > > .if defined(LOCALBASE) > > CFLAGS+= -DXAUTH_PATH=\"${LOCALBASE}/bin/xauth\" > > .endif > > Hello, > > This change makes the following simple test program fail on the second > assert. The problem is that sa_handler == SIG_DFL, and sa_flags == > SA_SIGINFO, which according to the sigaction(9) man page is not > possible. With this change reverted the test is successful. I do not quite follow.
What are the relations between sshd and your test program ?
Should the test be run somehow specially ?
>
> ---
> #include <signal.h>
> #include <string.h>
> #include <assert.h>
>
> int main(int argn, char **argv)
> {
> struct sigaction new, old;
> int rc;
>
> memset(&new, 0, sizeof(new));
> memset(&old, 0, sizeof(old));
>
> sigemptyset(&new.sa_mask);
> new.sa_handler = SIG_DFL;
> new.sa_flags = 0;
>
> rc = sigaction(SIGCHLD, &new, &old);
> assert(rc == 0);
> assert((old.sa_handler == SIG_DFL || old.sa_handler == SIG_IGN) &&
> !(old.sa_flags & SA_SIGINFO));
>
> return (0);
> }
>
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