Messages in this thread | | | From | Geert Uytterhoeven <> | Date | Thu, 26 Apr 2018 10:45:49 +0200 | Subject | Re: [PATCH v2 2/4] ARM: amba: Fix race condition with driver_override |
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Hi Greg,
On Thu, Apr 26, 2018 at 10:35 AM, Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote: > On Thu, Apr 26, 2018 at 09:40:08AM +0200, Geert Uytterhoeven wrote: >> On Thu, Apr 26, 2018 at 9:04 AM, Greg Kroah-Hartman >> <gregkh@linuxfoundation.org> 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 >> >> <gregkh@linuxfoundation.org> 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 <geert+renesas@glider.be> >> >> >> Reviewed-by: Todd Kjos <tkjos@google.com> >> >> >> Cc: stable <stable@vger.kernel.org> >> >> >> >> > 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 :)
Np, issue detected and fixed. Thanks!
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
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