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bug#10641: [2.0.3+] start_signal_delivery_thread failure on x86_64-freeb
From: |
Andy Wingo |
Subject: |
bug#10641: [2.0.3+] start_signal_delivery_thread failure on x86_64-freebsd8.2 |
Date: |
Wed, 13 Mar 2013 11:02:41 +0100 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/24.2 (gnu/linux) |
Hi,
On Sun 29 Jan 2012 19:00, address@hidden (Ludovic Courtès) writes:
> Adding printfs shows that the thread calling scm_spawn_thread leaves
> cond_wait before the signal thread has signaled the condition (in
> really_spawn).
>From
>http://pubs.opengroup.org/onlinepubs/009604599/functions/pthread_cond_wait.html
When using condition variables there is always a Boolean predicate
involving shared variables associated with each condition wait that is
true if the thread should proceed. Spurious wakeups from the
pthread_cond_timedwait() or pthread_cond_wait() functions may
occur. Since the return from pthread_cond_timedwait() or
pthread_cond_wait() does not imply anything about the value of this
predicate, the predicate should be re-evaluated upon such return.
It seems this code is not robust in the face of spurious wakeups. I
pushed a patch that waits for data.thread to become non-false. That
should fix this issue.
Cheers,
Andy
--
http://wingolog.org/
- bug#10641: [2.0.3+] start_signal_delivery_thread failure on x86_64-freebsd8.2,
Andy Wingo <=