[PATCH] Re: bin/32295: pthread dont dequeue signals
Andrew Belashov
bel at orel.ru
Fri Sep 10 03:40:31 PDT 2004
The following reply was made to PR bin/32295; it has been noted by GNATS.
From: Andrew Belashov <bel at orel.ru>
To: freebsd-gnats-submit at FreeBSD.org, freebsd-threads at FreeBSD.org
Cc:
Subject: [PATCH] Re: bin/32295: pthread dont dequeue signals
Date: Fri, 10 Sep 2004 14:31:27 +0400
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Hello, All!
About one year I use my patch for open PR bin/32295.
No problem detected on high load mysql server. Also, this patch
tested with mozilla and firefox.
Patch in attachment. Alternate location:
<http://www.orel.ru/~bel/patches/uthread_sig.c.diff>
Problem description:
In function _thread_sig_handler() received signal queued (by writing into pipe).
===============================================================================
if (_queue_signals != 0) {
__sys_write(_thread_kern_pipe[1], &c, 1);
DBG_MSG("Got signal %d, queueing to kernel pipe\n", sig);
}
===============================================================================
But flag _sigq_check_reqd (Check of queue of signals is required) is not touched
if signal should be ignored:
===============================================================================
if (_thread_sigq[sig - 1].blocked == 0) {
[.........]
/* Indicate that there are queued signals: */
_thread_sigq[sig - 1].pending = 1;
_sigq_check_reqd = 1;
}
/* These signals need special handling: */
else if (sig == SIGCHLD || sig == SIGTSTP ||
sig == SIGTTIN || sig == SIGTTOU) {
_thread_sigq[sig - 1].pending = 1;
_thread_sigq[sig - 1].signo = sig;
_sigq_check_reqd = 1;
}
else {
DBG_MSG("Got signal %d, ignored.\n", sig);
}
===============================================================================
In this situation, dequeue signal handler is not executed and signal
does not dequeued from pipe...
This is bug and patch should be commited.
--
With best regards,
Andrew Belashov.
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filename="uthread_sig.c.diff"
--- lib/libc_r/uthread/uthread_sig.c.orig Wed Dec 3 09:54:40 2003
+++ lib/libc_r/uthread/uthread_sig.c Fri Sep 10 10:50:32 2004
@@ -160,8 +160,10 @@
_thread_sigq[sig - 1].signo = sig;
_sigq_check_reqd = 1;
}
- else
+ else {
DBG_MSG("Got signal %d, ignored.\n", sig);
+ _sigq_check_reqd = 1;
+ }
}
/*
* The signal handlers should have been installed so that they
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