From: ludo@gnu.org (Ludovic Courtès)
To: Sergei Trofimovich <slyfox@gentoo.org>
Cc: 29151-done@debbugs.gnu.org
Subject: bug#29151: [PATCH] ia64: fix crash in thread context switch
Date: Wed, 22 Nov 2017 16:16:17 +0100 [thread overview]
Message-ID: <87tvxmxs1q.fsf@gnu.org> (raw)
In-Reply-To: <20171105093045.10066-1-slyfox@gentoo.org> (Sergei Trofimovich's message of "Sun, 5 Nov 2017 09:30:45 +0000")
Hi Sergei,
Sergei Trofimovich <slyfox@gentoo.org> skribis:
> Backtrace looks like that:
>
> Program terminated with signal SIGSEGV, Segmentation fault.
> #0 0x200000000014a5c0 in scm_ia64_longjmp (JB=0x6000000000817020, VAL=1) at continuations.c:372
> 372 t->pending_rbs_continuation->backing_store,
> [Current thread is 1 (Thread 0x2000000000049340 (LWP 8190))]
> (gdb) bt
> #0 0x200000000014a5c0 in scm_ia64_longjmp (JB=0x6000000000817020, VAL=1) at continuations.c:372
> #1 0x2000000000148e00 in scm_c_abort (vm=0x60000000000edea0, tag=0x6000000000795ba0, n=0, argv=0x60000fffff7f0ce0, cookie=-1) at control.c:239
> #2 0x2000000000149070 in scm_at_abort (tag=0x6000000000795ba0, args=0x304) at control.c:258
> (gdb) print t
> $2 = (scm_i_thread *) 0x6000000000068000
> (gdb) print t->pending_rbs_continuation
> $3 = (scm_t_contregs *) 0xffeb
>
> The problem here is the value of 't->pending_rbs_continuation' pointer.
> It's supposed to poin to a register stack pointer or be NULL if not yet
> backed up.
>
> The problem is it is never initialized to NULL at creation time and
> contained garbage on stack. Sometimes people are lucky and have zeros
> on stack and guile works. But sometimes there is something and guile
> crashes.
>
> The fix is trivial: initialize 'pending_rbs_continuation = NULL'
> at thread registration time (the same way other threads are registered).
>
> Reported-by: Matt Turner
> Bug: https://bugs.gentoo.org/613986
>
> * libguile/threads.c(guilify_self_1): initialize pending_rbs_continuation
> to avoid guile crash on ia64.
I’ve applied the patch to the ‘stable-2.2’ branch, thank you, and thanks
to Jason for testing!
Ludo’.
next prev parent reply other threads:[~2017-11-22 15:16 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-05 9:30 bug#29151: [PATCH] ia64: fix crash in thread context switch Sergei Trofimovich
2017-11-22 15:16 ` Ludovic Courtès [this message]
2017-11-26 19:37 ` Sergei Trofimovich
2017-11-26 20:32 ` Ludovic Courtès
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