Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932118AbbFWHQb (ORCPT ); Tue, 23 Jun 2015 03:16:31 -0400 Received: from mail-ob0-f182.google.com ([209.85.214.182]:34833 "EHLO mail-ob0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751483AbbFWHQV (ORCPT ); Tue, 23 Jun 2015 03:16:21 -0400 MIME-Version: 1.0 In-Reply-To: <5913118.ZpKlm0JFgd@vostro.rjw.lan> References: <1434622954-26747-3-git-send-email-geert+renesas@glider.be> <1434958282-27376-1-git-send-email-geert+renesas@glider.be> <5913118.ZpKlm0JFgd@vostro.rjw.lan> Date: Tue, 23 Jun 2015 09:16:21 +0200 X-Google-Sender-Auth: 35pmOwvIqdD7D_swOlSJvl2rJUI Message-ID: Subject: Re: [PATCH 2/2] PM / Domains: Avoid infinite loops in attach/detach code From: Geert Uytterhoeven To: "Rafael J. Wysocki" Cc: Geert Uytterhoeven , Daniel Lezcano , Thomas Gleixner , Kevin Hilman , Ulf Hansson , Magnus Damm , Laurent Pinchart , Linux PM list , Linux-sh list , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1442 Lines: 37 Hi Rafael, On Tue, Jun 23, 2015 at 1:41 AM, Rafael J. Wysocki wrote: > On Monday, June 22, 2015 09:31:22 AM Geert Uytterhoeven wrote: >> If pm_genpd_{add,remove}_device() keeps on failing with -EAGAIN, we end >> up with an infinite loop in genpd_dev_pm_{at,de}tach(). >> >> This may happen due to a genpd.prepared_count imbalance. This is a bug >> elsewhere, but it will result in a system lock up, possibly during >> reboot of an otherwise functioning system. >> >> To avoid this, put a limit on the maximum number of loop iterations, >> including a simple back-off mechanism. If the limit is reached, the >> operation will just fail. An error message is already printed. >> >> Signed-off-by: Geert Uytterhoeven > > This was too late for my first 4.2 pull request, but I may push it in the > second half of the merge window. Does it depend on anything? Not that I'm aware of. It applies fine on v4.1 or next-20150622. 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in Please read the FAQ at http://www.tux.org/lkml/