[PATCH] fix potential hang in cpqphp

[PATCH] fix potential hang in cpqphp

[Zink, Dan]

Someone reported a hang when shutting down their system when cpqphp was
built in.
Ron Urwin tracked this down to a long standing bug in the event thread.
It's not
meant to receive signals but we weren't masking them either.  Here is
Ron's patch
for 2.4.26.  From the looks of it, 2.6 changed the semantics so that
signals are
masked by default.  Is that right?

Thanks,
Dan


diff -Nuar linux-2.4.26/drivers/hotplug/cpqphp_ctrl.c
linux-2.4.26-working/drivers/hotplug/cpqphp_ctrl.c
--- linux-2.4.26/drivers/hotplug/cpqphp_ctrl.c	2003-11-28
12:26:20.000000000 -0600
+++ linux-2.4.26-working/drivers/hotplug/cpqphp_ctrl.c	2004-06-29
10:36:20.840104456 -0500
@@ -1726,7 +1726,14 @@
 	
 	//  New name
 	strcpy(current->comm, "phpd_event");
-	
+
+	/* avoid getting signals */
+	spin_lock_irq(&current->sigmask_lock);
+	flush_signals(current);
+	sigfillset(&current->blocked);
+	recalc_sigpending(current);
+	spin_unlock_irq(&current->sigmask_lock);
+
 	unlock_kernel();
 
 	while (1) {


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Re: [PATCH] fix potential hang in cpqphp

[Greg KH]

On Tue, Jun 29, 2004 at 01:56:45PM -0500, Zink, Dan wrote:
> Someone reported a hang when shutting down their system when cpqphp was
> built in.
> Ron Urwin tracked this down to a long standing bug in the event thread.
> It's not
> meant to receive signals but we weren't masking them either.  Here is
> Ron's patch
> for 2.4.26.  From the looks of it, 2.6 changed the semantics so that
> signals are
> masked by default.  Is that right?

I think so, yes.

But your patch is line-wrapped, care to resend it with the same comments
again?

thanks,

greg k-h


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RE: [PATCH] fix potential hang in cpqphp

[Zink, Dan]

[-- Attachment #1: Type: text/plain, Size: 900 bytes --]

Here is the patch as an attachment since our mailer won't cooperate.

Thanks,
Dan

-----Original Message-----
From: Greg KH [mailto:greg@kroah.com] 
Sent: Wednesday, June 30, 2004 6:03 PM
To: Zink, Dan
Cc: linux-hotplug-devel@lists.sourceforge.net; Urwin, Ron
Subject: Re: [PATCH] fix potential hang in cpqphp

On Tue, Jun 29, 2004 at 01:56:45PM -0500, Zink, Dan wrote:
> Someone reported a hang when shutting down their system when cpqphp 
> was built in.
> Ron Urwin tracked this down to a long standing bug in the event
thread.
> It's not
> meant to receive signals but we weren't masking them either.  Here is 
> Ron's patch for 2.4.26.  From the looks of it, 2.6 changed the 
> semantics so that signals are masked by default.  Is that right?

I think so, yes.

But your patch is line-wrapped, care to resend it with the same comments
again?

thanks,

greg k-h



[-- Attachment #2: cpqphp_signal.patch --]
[-- Type: application/octet-stream, Size: 604 bytes --]

diff -Nuar linux-2.4.26/drivers/hotplug/cpqphp_ctrl.c linux-2.4.26-working/drivers/hotplug/cpqphp_ctrl.c
--- linux-2.4.26/drivers/hotplug/cpqphp_ctrl.c	2003-11-28 12:26:20.000000000 -0600
+++ linux-2.4.26-working/drivers/hotplug/cpqphp_ctrl.c	2004-06-29 10:36:20.840104456 -0500
@@ -1726,7 +1726,14 @@
 	
 	//  New name
 	strcpy(current->comm, "phpd_event");
-	
+
+	/* avoid getting signals */
+	spin_lock_irq(&current->sigmask_lock);
+	flush_signals(current);
+	sigfillset(&current->blocked);
+	recalc_sigpending(current);
+	spin_unlock_irq(&current->sigmask_lock);
+
 	unlock_kernel();
 
 	while (1) {

Re: [PATCH] fix potential hang in cpqphp

[Greg KH]

On Wed, Jun 30, 2004 at 06:33:53PM -0500, Zink, Dan wrote:
> Here is the patch as an attachment since our mailer won't cooperate.

Thanks, that worked.  Applied.

greg k-h


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