Home » Mailing list archives » linux-kernel » 2007 » September » 11

Re: [PATCH] Fix failure to resume from initrds.

Previous thread: Oops in make_class_name in 2.6.22.1 on Fedora by Pete Zaitcev on Monday, September 10, 2007 - 11:26 pm. (6 messages)

Next thread: [04/41] Use page_cache_xxx in mm/page-writeback.c by Christoph Lameter on Tuesday, September 11, 2007 - 2:03 am. (1 message)
[view original message]
From: Nigel Cunningham <nigel@...>
To: LKML <linux-kernel@...>, Linus Torvalds <torvalds@...>, Rafael Wysocki <rjw@...>
Subject: [PATCH] Fix failure to resume from initrds.
Date: Monday, September 10, 2007 - 11:54 pm

Hi all.


Commit 831441862956fffa17b9801db37e6ea1650b0f69 (Freezer: make kernel threads

nonfreezable by default) breaks freezing when attempting to resume from an

initrd, because the init (which is freezeable) spins while waiting for another

thread to run /linuxrc, but doesn't check whether it has been told to enter

the refrigerator. The original patch replaced a call to try_to_freeze() with a

call to yield(). I believe a simple reversion is wrong because

if !CONFIG_PM_SLEEP, try_to_freeze() is a noop. It should still yield.


Signed-off-by: Nigel Cunningham <nigel@nigel.suspend2.net>


 do_mounts_initrd.c |    4 +++-

 1 file changed, 3 insertions(+), 1 deletion(-)

diff -ruNp 952-fix-initrd-resume.patch-old/init/do_mounts_initrd.c 952-fix-initrd-resume.patch-new/init/do_mounts_initrd.c

--- 952-fix-initrd-resume.patch-old/init/do_mounts_initrd.c	2007-09-11 13:43:31.000000000 +1000

+++ 952-fix-initrd-resume.patch-new/init/do_mounts_initrd.c	2007-09-11 13:19:50.000000000 +1000

@@ -58,8 +58,10 @@ static void __init handle_initrd(void)


 	pid = kernel_thread(do_linuxrc, "/linuxrc", SIGCHLD);

 	if (pid > 0)

-		while (pid != sys_wait4(-1, NULL, 0, NULL))

+		while (pid != sys_wait4(-1, NULL, 0, NULL)) {

 			yield();

+			try_to_freeze();

+		}


 	if (!resume_attempted)

 		printk(KERN_ERR "Suspend2: No attempt was made to resume from "


--

See http://www.tuxonice.net for Howtos, FAQs, mailing

lists, wiki and bugzilla info.

-
[view original message]
From: Rafael J. Wysocki <rjw@...>
To: <nigel@...>
Cc: LKML <linux-kernel@...>, Linus Torvalds <torvalds@...>
Subject: Re: [PATCH] Fix failure to resume from initrds.
Date: Tuesday, September 11, 2007 - 7:04 am

Hm.


I use a resume from an initrd on a regular basis and it works without the patch

below.


Greetings,

Rafael

-
[view original message]
From: Nigel Cunningham <ncunningham@...>
To: Rafael J. Wysocki <rjw@...>
Cc: <nigel@...>, LKML <linux-kernel@...>, Linus Torvalds <torvalds@...>
Subject: Re: [PATCH] Fix failure to resume from initrds.
Date: Tuesday, September 11, 2007 - 7:27 am

Hi.


Ah. That makes me realise that I see that too - my AMD64 uniprocessor laptop

didn't need the patch (guess that's why I didn't notice the need and ack'd

the patch). But my x86 SMP machine... it needs this. I'll see if they're

running on different processors.


Regards,


Nigel

--

Nigel Cunningham

Christian Reformed Church of Cobden

103 Curdie Street, Cobden 3266, Victoria, Australia

Ph. +61 3 5595 1185 / +61 417 100 574

Communal Worship: 11 am Sunday.

-
[view original message]
From: Rafael J. Wysocki <rjw@...>
To: Nigel Cunningham <ncunningham@...>
Cc: <nigel@...>, LKML <linux-kernel@...>, Linus Torvalds <torvalds@...>
Subject: Re: [PATCH] Fix failure to resume from initrds.
Date: Tuesday, September 11, 2007 - 7:55 am

Well, strange.  My x86_64 SMP machines don't need the patch too.


Greetings,

Rafael

-
[view original message]
From: Nigel Cunningham <nigel@...>
To: Rafael J. Wysocki <rjw@...>
Cc: <nigel@...>, LKML <linux-kernel@...>, Linus Torvalds <torvalds@...>
Subject: Re: [PATCH] Fix failure to resume from initrds.
Date: Tuesday, September 11, 2007 - 9:01 am

Hi again.


Oh well. I'm probably doing something wrong then and haven't clicked yet.


Regards,


Nigel

--

See http://www.tuxonice.net for Howtos, FAQs, mailing

lists, wiki and bugzilla info.

-
[view original message]
From: Rafael J. Wysocki <rjw@...>
To: Nigel Cunningham <ncunningham@...>
Cc: <nigel@...>, LKML <linux-kernel@...>, Linus Torvalds <torvalds@...>, Pavel Machek <pavel@...>
Subject: Re: [PATCH] Fix failure to resume from initrds.
Date: Tuesday, September 11, 2007 - 9:12 am

Anyway, yes, init is freezable, but should it be?


I mean, shouldn't we rather add PF_NOFREEZE to kernel_init()?


Greetings,

Rafael

-
[view original message]
From: Rafael J. Wysocki <rjw@...>
To: Nigel Cunningham <ncunningham@...>
Cc: <nigel@...>, LKML <linux-kernel@...>, Linus Torvalds <torvalds@...>, Pavel Machek <pavel@...>, Andrew Morton <akpm@...>
Subject: Re: [PATCH] Fix failure to resume from initrds.
Date: Tuesday, September 11, 2007 - 9:23 am

Argh, no.  PF_NOFREEZE is inherited by the children.


So, I think that your patch is correct, but there's some suspend2-specific

stuff in it.  I've rediffed it against 2.6.23-rc6 and moved try_to_freeze()

before yield().


---

From: Nigel Cunningham <nigel@nigel.suspend2.net>


Commit 831441862956fffa17b9801db37e6ea1650b0f69 (Freezer: make kernel threads

nonfreezable by default) breaks freezing when attempting to resume from an

initrd, because the init (which is freezeable) spins while waiting for another

thread to run /linuxrc, but doesn't check whether it has been told to enter

the refrigerator. The original patch replaced a call to try_to_freeze() with a

call to yield(). I believe a simple reversion is wrong because

if !CONFIG_PM_SLEEP, try_to_freeze() is a noop. It should still yield.


Signed-off-by: Nigel Cunningham <nigel@nigel.suspend2.net>

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

---

 init/do_mounts_initrd.c |    4 +++-

 1 file changed, 3 insertions(+), 1 deletion(-)


Index: linux-2.6.23-rc6/init/do_mounts_initrd.c

===================================================================

--- linux-2.6.23-rc6.orig/init/do_mounts_initrd.c

+++ linux-2.6.23-rc6/init/do_mounts_initrd.c

@@ -57,8 +57,10 @@ static void __init handle_initrd(void)


 	pid = kernel_thread(do_linuxrc, "/linuxrc", SIGCHLD);

 	if (pid > 0)

-		while (pid != sys_wait4(-1, NULL, 0, NULL))

+		while (pid != sys_wait4(-1, NULL, 0, NULL)) {

+			try_to_freeze();

 			yield();

+		}


 	/* move initrd to rootfs' /old */

 	sys_fchdir(old_fd);

-
[view original message]
From: Linus Torvalds <torvalds@...>
To: Rafael J. Wysocki <rjw@...>
Cc: Nigel Cunningham <ncunningham@...>, <nigel@...>, LKML <linux-kernel@...>, Pavel Machek <pavel@...>, Andrew Morton <akpm@...>
Subject: Re: [PATCH] Fix failure to resume from initrds.
Date: Tuesday, September 11, 2007 - 10:39 am

[Empty message]
[view original message]
From: Pavel Machek <pavel@...>
To: Linus Torvalds <torvalds@...>
Cc: Rafael J. Wysocki <rjw@...>, Nigel Cunningham <ncunningham@...>, <nigel@...>, LKML <linux-kernel@...>, Andrew Morton <akpm@...>
Subject: Re: [PATCH] Fix failure to resume from initrds.
Date: Tuesday, September 11, 2007 - 12:27 pm

We want to do resume sometime around here, and resume wants to run

with userspace frozen, as does suspend.

									Pavel

--

(english) http://www.livejournal.com/~pavelmachek

(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

-
[view original message]
From: Nigel Cunningham <nigel@...>
To: Rafael J. Wysocki <rjw@...>
Cc: <nigel@...>, LKML <linux-kernel@...>, Linus Torvalds <torvalds@...>, Pavel Machek <pavel@...>, Andrew Morton <akpm@...>
Subject: Re: [PATCH] Fix failure to resume from initrds.
Date: Tuesday, September 11, 2007 - 9:41 am

[Empty message]
[view original message]
From: Rafael J. Wysocki <rjw@...>
To: <nigel@...>
Cc: LKML <linux-kernel@...>, Linus Torvalds <torvalds@...>, Pavel Machek <pavel@...>, Andrew Morton <akpm@...>
Subject: Re: [PATCH] Fix failure to resume from initrds.
Date: Tuesday, September 11, 2007 - 3:25 pm

Technically it's not that important, but conceptually try_to_freeze() should


Well, I guess it'll take some time to get that work reliable and it would be

nice to have a fix before it's ready.


Greetings,

Rafael

-
Previous thread: Oops in make_class_name in 2.6.22.1 on Fedora by Pete Zaitcev on Monday, September 10, 2007 - 11:26 pm. (6 messages)

Next thread: [04/41] Use page_cache_xxx in mm/page-writeback.c by Christoph Lameter on Tuesday, September 11, 2007 - 2:03 am. (1 message)