linux-kernel - Re: [PATCH] kgdbts: fix hw_access_break

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Message-ID: <2024081410-scrabble-drizzly-3005@gregkh>
Date: Wed, 14 Aug 2024 17:55:17 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: Daniel Thompson <daniel.thompson@...aro.org>
Cc: Doug Anderson <dianders@...omium.org>,
	Florian Rommel <mail@...rommel.de>,
	Jason Wessel <jason.wessel@...driver.com>,
	Arnd Bergmann <arnd@...db.de>, kgdb-bugreport@...ts.sourceforge.net,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] kgdbts: fix hw_access_break_test

On Wed, Aug 14, 2024 at 04:38:43PM +0100, Daniel Thompson wrote:
> On Mon, Aug 12, 2024 at 01:04:22PM -0700, Doug Anderson wrote:
> > Hi,
> >
> > On Mon, Aug 12, 2024 at 1:55 AM Florian Rommel <mail@...rommel.de> wrote:
> > >
> > > The test for access watchpoints (hw_access_break_test) was broken
> > > (always failed) because the compiler optimized out the write to the
> > > static helper variable (hw_break_val2), as it is never read anywhere.
> > > This resulted in the target variable (hw_break_val) not being accessed
> > > and thus the breakpoint not being triggered.
> > >
> > > Remove the helper variable (hw_break_val2), and use READ_ONCE to force
> > > reading the target variable (hw_break_val).
> > >
> > > Signed-off-by: Florian Rommel <mail@...rommel.de>
> > > ---
> > >  drivers/misc/kgdbts.c | 4 ++--
> > >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > Reviewed-by: Douglas Anderson <dianders@...omium.org>
> 
> Looks good. I pushed this through kgdbtest and it likes it too. I can
> turn one of the XFAILs off (yay).
> 
> Acked-by: Daniel Thompson <daniel.thompson@...aro.org>
> Tested-by: Daniel Thompson <daniel.thompson@...aro.org>
> 
> Arnd/Greg: Are you happy to pick this up or should I take it through the kgdb
> tree? FWIW right now there are zero other patches for kgdb this cycle, although
> that could change!

I've already picked it up, thanks!

greg k-h