linux-kernel - Re: [PATCH] ARM: kexec: Fix panic after TLB are invalidated

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Date:   Thu, 4 Feb 2021 23:48:42 +0000
From:   Giancarlo Ferrari <giancarlo.ferrari89@...il.com>
To:     Russell King - ARM Linux admin <linux@...linux.org.uk>
Cc:     Mark Rutland <mark.rutland@....com>, linux-kernel@...r.kernel.org,
        penberg@...nel.org, geert@...ux-m68k.org,
        linux-arm-kernel@...ts.infradead.org, akpm@...ux-foundation.org,
        rppt@...nel.org, giancarlo.ferrari@...ia.com
Subject: Re: [PATCH] ARM: kexec: Fix panic after TLB are invalidated

Hi all,

On Mon, Feb 01, 2021 at 10:18:26PM +0000, Giancarlo Ferrari wrote:
> Russell,
> 
> On Mon, Feb 01, 2021 at 08:16:33PM +0000, Russell King - ARM Linux admin wrote:
> > On Mon, Feb 01, 2021 at 08:07:37PM +0000, Giancarlo Ferrari wrote:
> > > Hi,
> > 
> > Hi,
> > 
> > > Why we should align 3 ? For the fncpy I suppose.
> > 
> > Slightly arbitary really - it gives a nice 8-byte alignment to the data.
> > .align 2 would also be sufficient.
> > 
> > > I don't know now how to proceed now, as you (Mark and you) do completely
> > > the patch.
> > 
> > Please can you test my patch and let us know if it solves your problem
> > (or even if it works! I haven't tested it beyond build-testing.)
> >

I have tested your patch and it works. I have tested using kexec -l/kexec -e.
Considering that .text var are no more written, I assume the issue is gone.

> 
> sure, unfortunately due to restriction, I hope to test it by the end of the
> week. I hope there will be no rush. Otherwise, please let me know.
> 
> > > You see is my first kernel patch submission :) .
> > 
> > Yay. Sorry for giving you a different patch - Mark is quite right that
> > there's a better solution to this problem, which is eliminating the
> > set_kernel_text_rw() call. The only reason I cooked up the patch was
> > doing that would be more in-depth (as you can see from the increased
> > size of the patch.)
> > 
> 
> I definitely agree with you.
> 
> > -- 
> > RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
> > FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
> 
> Thanks again,
> 
> 
> GF

Can I ask about having it integrated ?

Thanks in advance,


GF