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

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Message-Id: <200709111304.23263.rjw@sisk.pl>
Date:	Tue, 11 Sep 2007 13:04:22 +0200
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	nigel@...pend2.net
Cc:	LKML <linux-kernel@...r.kernel.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [PATCH] Fix failure to resume from initrds.

On Tuesday, 11 September 2007 05:54, Nigel Cunningham wrote:
> 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.

Hm.

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

I think we need to investigate what happens in your test case a bit.

> 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@...el.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 "
> 

Greetings,
Rafael
-
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