Date: Tue, 06 Aug 2002 09:25:21 -0700 (PDT) From: John Polstra <jdp@polstra.com> To: Martin Blapp <mb@imp.ch> Cc: hackers@FreeBSD.ORG, openoffice@FreeBSD.ORG, Alexander Kabaev <ak03@gte.com> Subject: Re: Help needed. Deadlock in rtld makes openoffice build hang ag Message-ID: <XFMail.20020806092521.jdp@polstra.com> In-Reply-To: <20020806095745.M58571-100000@levais.imp.ch>
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Martin Blapp wrote:
>
> From 10 builds, about 6 are hanging, and I need to restart them.
>
> This is not a usable solution for a package building cluster.
>
> I end with a process consuming all CPU resources and hanging for
> waiting for a lock to get released what never happens.
>
> Problem is exit(). Replaceing exit() with _exit() did not help.
>
> [Switching to Process 4968, Thread 1]
> 0x28050784 in sigprocmask () from /usr/libexec/ld-elf.so.1
> (gdb) bt
>#0 0x28050784 in sigprocmask () from /usr/libexec/ld-elf.so.1
>#1 0x2804f2d1 in xprintf () from /usr/libexec/ld-elf.so.1
>#2 0x2804df78 in find_symdef () from /usr/libexec/ld-elf.so.1
>#3 0x2838dbd8 in exit () from /usr/lib/libc_r.so.4
>#4 0x08048c77 in _start ()
>
> I tried to add the following lines as proposed by Alexander Kabaev
> to libexec/rtld-elf/i386/lockdflt.c
[...]
The lock algorithms are taken from the paper referenced in the comment
at the top of lockdflt.c, and I believe they are correct. Whatever is
happening must be caused by changes in libc_r that cause the profiling
timer to stop advancing, or cause SIGPROF to be blocked. There were
some major changes made to libc_r on 13 Oct 2000 that could be
connected with this.
Just as an experiment, please try this change to lockdflt_init() in
rtld-elf/i386/lockdflt.c:
Index: lockdflt.c
===================================================================
RCS file: /home/ncvs/src/libexec/rtld-elf/i386/lockdflt.c,v
retrieving revision 1.5.2.4
diff -U5 -r1.5.2.4 lockdflt.c
--- lockdflt.c 11 Jul 2002 23:52:32 -0000 1.5.2.4
+++ lockdflt.c 6 Aug 2002 16:23:33 -0000
@@ -263,10 +263,11 @@
/*
* Construct a mask to block all signals except traps which might
* conceivably be generated within the dynamic linker itself.
*/
sigfillset(&fullsigmask);
+ sigdelset(&fullsigmask, SIGPROF);
sigdelset(&fullsigmask, SIGILL);
sigdelset(&fullsigmask, SIGTRAP);
sigdelset(&fullsigmask, SIGABRT);
sigdelset(&fullsigmask, SIGEMT);
sigdelset(&fullsigmask, SIGFPE);
John
PS - Are you working with -stable or with -current?
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