linux-kernel - Re: [PATCH] avr32: init cannot ignore signals sent by force_sig

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Message-ID: <1302700488.10549.2.camel@hcegtvedt>
Date:	Wed, 13 Apr 2011 15:14:48 +0200
From:	Hans-Christian Egtvedt <hans-christian.egtvedt@...el.com>
To:	Matt Fleming <matt@...sole-pimps.org>
Cc:	linux-kernel@...r.kernel.org, Oleg Nesterov <oleg@...hat.com>,
	Matt Fleming <matt.fleming@...ux.intel.com>
Subject: Re: [PATCH] avr32: init cannot ignore signals sent by
 force_sig_info()

On Mon, 2011-04-04 at 15:58 +0100, Matt Fleming wrote: 
> From: Matt Fleming <matt.fleming@...ux.intel.com>
> 
> We can delete the code that checks to see if we're sending an ignored
> signal to init because force_sig_info() already handles this case.
> force_sig_info() will kill init even if the signal handler is SIG_DFL
> and the scenario described in the comment where init might "generate
> the same exception over and over again" cannot occur (force_sig_info()
> clears SIGNAL_UNKILLABLE to ensure that init will die).
> 
> Also, the use of is_global_init() is not correct in the multhreaded
> case, as Oleg Nesterov explains,
> 
> 	"is_global_init() is not right in theory, /sbin/init can be
> 	multithreaded. And, this doesn't cover the sub-namespace
> 	inits... I'd suggest to check SIGNAL_UNKILLABLE, but looking
> 	closer I think you can simply remove this code."
> 
> It seems this code was copied from arch/powerpc in March 2007 in commit
> 
>   623b0355d5b1 "[AVR32] Clean up exception handling code"
> 
> but the code was deleted from arch/powerpc in November 2009 in commit
> 
>   a0592d42fe3e "powerpc: kill the obsolete code under is_global_init()"
> 
> So catch up with powerpc and delete the bogus code.
> 
> Signed-off-by: Matt Fleming <matt.fleming@...ux.intel.com>

Thanks for this cleanup, added to the AVR32 tree.

Signed-off-by: Hans-Christian Egtvedt <hans-christian.egtvedt@...el.com>

-- 
Hans-Christian Egtvedt

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