From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A07DAC43613 for ; Mon, 24 Jun 2019 06:45:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7878320820 for ; Mon, 24 Jun 2019 06:45:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726579AbfFXGpD (ORCPT ); Mon, 24 Jun 2019 02:45:03 -0400 Received: from 178.115.242.59.static.drei.at ([178.115.242.59]:43903 "EHLO mail.osadl.at" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725267AbfFXGpD (ORCPT ); Mon, 24 Jun 2019 02:45:03 -0400 X-Greylist: delayed 389 seconds by postgrey-1.27 at vger.kernel.org; Mon, 24 Jun 2019 02:45:02 EDT Received: by mail.osadl.at (Postfix, from userid 1001) id C37BB5C02F0; Mon, 24 Jun 2019 08:37:18 +0200 (CEST) Date: Mon, 24 Jun 2019 08:37:18 +0200 From: Nicholas Mc Guire To: Christophe JAILLET Cc: eric@anholt.net, stefan.wahren@i2se.com, gregkh@linuxfoundation.org, f.fainelli@gmail.com, rjui@broadcom.com, sbranden@broadcom.com, bcm-kernel-feedback-list@broadcom.com, tuomas.tynkkynen@iki.fi, inf.braun@fau.de, tobias.buettner@fau.de, hofrat@osadl.org, linux-rpi-kernel@lists.infradead.org, linux-arm-kernel@lists.infradead.org, devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org Subject: Re: [PATCH] staging: bcm2835-camera: Avoid apotential sleep while holding a spin_lock Message-ID: <20190624063718.GD31913@osadl.at> References: <20190624053351.5217-1-christophe.jaillet@wanadoo.fr> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190624053351.5217-1-christophe.jaillet@wanadoo.fr> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 24, 2019 at 07:33:51AM +0200, Christophe JAILLET wrote: > Do not allocate memory with GFP_KERNEL when holding a spin_lock, it may > sleep. Use GFP_NOWAIT instead. > checking for this in the rest of the kernel with a cocci spatch virtual report @nonatomic@ position p; identifier var; @@ spin_lock(...) ... when != spin_unlock(...) * var = idr_alloc@p(...,GFP_KERNEL); ... when != spin_unlock(...) spin_unlock(...); this seems to be the only instance of this specific problem. > Fixes: 950fd867c635 ("staging: bcm2835-camera: Replace open-coded idr with a struct idr.") The GFP_KERNEL actually was there befor this patch so not sure if this Fixes ref is correct - I think the GFP_KERNEL was introduced in: 4e6bafdfb9f3 ("staging: bcm2835_camera: Use a mapping table for context field of mmal_msg_header") > Signed-off-by: Christophe JAILLET Reviewed-by: Nicholas Mc Guire > --- > drivers/staging/vc04_services/bcm2835-camera/mmal-vchiq.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/staging/vc04_services/bcm2835-camera/mmal-vchiq.c b/drivers/staging/vc04_services/bcm2835-camera/mmal-vchiq.c > index 16af735af5c3..438d548c6e24 100644 > --- a/drivers/staging/vc04_services/bcm2835-camera/mmal-vchiq.c > +++ b/drivers/staging/vc04_services/bcm2835-camera/mmal-vchiq.c > @@ -186,7 +186,7 @@ get_msg_context(struct vchiq_mmal_instance *instance) > */ > spin_lock(&instance->context_map_lock); > handle = idr_alloc(&instance->context_map, msg_context, > - 0, 0, GFP_KERNEL); > + 0, 0, GFP_NOWAIT); > spin_unlock(&instance->context_map_lock); > > if (handle < 0) { > -- > 2.20.1 >