From mboxrd@z Thu Jan 1 00:00:00 1970 From: alexander.shishkin@linux.intel.com (Alexander Shishkin) Date: Fri, 23 Nov 2012 11:01:24 +0200 Subject: [PATCH v3 3/7] usb: chipidea: usbmisc: fix a potential race condition In-Reply-To: <20121123073711.GJ10369@pengutronix.de> References: <1353506793-8354-1-git-send-email-m.grzeschik@pengutronix.de> <1353506793-8354-4-git-send-email-m.grzeschik@pengutronix.de> <20121123053635.GB22420@nchen-desktop> <20121123073711.GJ10369@pengutronix.de> Message-ID: <87sj804rrv.fsf@ashishki-desk.ger.corp.intel.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Sascha Hauer writes: > On Fri, Nov 23, 2012 at 01:36:36PM +0800, Peter Chen wrote: >> On Wed, Nov 21, 2012 at 03:06:29PM +0100, Michael Grzeschik wrote: >> > From: Marc Kleine-Budde >> > >> > This fixes a potential race condition where the ci13xxx_imx glue code >> > could be fast enough to call one of the usbmisc_ops before he got a >> > valid value on the static usbmisc pointer. To fix that we first set >> > usbmisc, then call usbmisc_set_ops(). >> >> usbmisc is subsys_initcall, and cil13xxx_imx is module_init. Any >> potential situation that the ci13xxx_imx's probe is ran before the >> usbmisc's probe is completed? > > Not having looked at the code you are referring to at all I just want > to say that: drivers can be modules (don't know if that's true for > chipidea) and sooner or later we'll probably get devicetree overlays, ChipIdea can be not even one, but two modules (ci_hdrc, the actual controller driver, always a platform_driver) and platform bindings like ci13xxx_imx, ci13xxx_pci, ci13xxx_msm, which can be platform or pci or whatever else drivers. > so the devicetree nodes might just appear during runtime. Depending on > initcall order is generally not a good idea. That's very true. Regards, -- Alex