From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 26 Apr 2018 10:35:42 +0200 From: Greg Kroah-Hartman To: Geert Uytterhoeven Cc: Geert Uytterhoeven , Russell King , Adrian Salido , Nicolai Stange , Sasha Levin , Todd Kjos , Linux Kernel Mailing List Subject: Re: [PATCH v2 2/4] ARM: amba: Fix race condition with driver_override Message-ID: <20180426083542.GA31073@kroah.com> References: <1523366506-19832-1-git-send-email-geert+renesas@glider.be> <1523366506-19832-3-git-send-email-geert+renesas@glider.be> <20180425160645.GA16732@kroah.com> <20180426070410.GM14025@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.5 (2018-04-13) X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Thu, Apr 26, 2018 at 09:40:08AM +0200, Geert Uytterhoeven wrote: > Hi Greg, > > On Thu, Apr 26, 2018 at 9:04 AM, Greg Kroah-Hartman > wrote: > > On Wed, Apr 25, 2018 at 07:53:06PM +0200, Geert Uytterhoeven wrote: > >> On Wed, Apr 25, 2018 at 6:06 PM, Greg Kroah-Hartman > >> wrote: > >> > On Tue, Apr 10, 2018 at 03:21:44PM +0200, Geert Uytterhoeven wrote: > >> >> The driver_override implementation is susceptible to a race condition > >> >> when different threads are reading vs storing a different driver > >> >> override. Add locking to avoid this race condition. > >> >> > >> >> Cfr. commits 6265539776a0810b ("driver core: platform: fix race > >> >> condition with driver_override") and 9561475db680f714 ("PCI: Fix race > >> >> condition with driver_override"). > >> >> > >> >> Fixes: 3cf385713460eb2b ("ARM: 8256/1: driver coamba: add device binding path 'driver_override'") > >> >> Signed-off-by: Geert Uytterhoeven > >> >> Reviewed-by: Todd Kjos > >> >> Cc: stable > >> > >> > As this should go to stable kernels, I've fixed it up to apply without > >> > patch 1 as that's not a real "fix" that anyone needs... > >> > > >> > Please try to remember to put fixes first, and then "trivial" things > >> > later on in a series. > >> > >> I did it on purpose, as the fix is much more ugly without patch 1 applied. > >> Can't you just take patch 1, too? More consistency is always nice, even for > >> stable ;-) > > > > Consistency is nice, but when you have bug fixes that rely on "trivial" > > patches, it's usually not nice :( > > > > I already committed patch 2 to my tree without 1, so let's leave it > > as-is for now. > > Unfortunately the version you committed is buggy: the race condition > also covers the NULL check removed by the trivial patch you skipped, > so now you can get inconsistent behavior (no output or "(null)") on the > same running kernel version... > > Please revert and apply both. Thanks! Ugh, you are right, sorry about that. I've reverted the offending patch, and added them in the correct order now, I should have listened to you :) greg k-h