From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-la0-f44.google.com (mail-la0-f44.google.com [209.85.215.44]) by kanga.kvack.org (Postfix) with ESMTP id 2C1ED6B0069 for ; Thu, 23 Oct 2014 12:53:44 -0400 (EDT) Received: by mail-la0-f44.google.com with SMTP id hs14so1225657lab.3 for ; Thu, 23 Oct 2014 09:53:42 -0700 (PDT) Received: from mail-la0-x22e.google.com (mail-la0-x22e.google.com. [2a00:1450:4010:c03::22e]) by mx.google.com with ESMTPS id b9si3504254lbp.50.2014.10.23.09.53.41 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Thu, 23 Oct 2014 09:53:41 -0700 (PDT) Received: by mail-la0-f46.google.com with SMTP id gi9so1201911lab.5 for ; Thu, 23 Oct 2014 09:53:40 -0700 (PDT) From: Michal Nazarewicz Subject: Re: [PATCH 1/4] mm: cma: Don't crash on allocation if CMA area can't be activated In-Reply-To: <1414074828-4488-2-git-send-email-laurent.pinchart+renesas@ideasonboard.com> References: <1414074828-4488-1-git-send-email-laurent.pinchart+renesas@ideasonboard.com> <1414074828-4488-2-git-send-email-laurent.pinchart+renesas@ideasonboard.com> Date: Thu, 23 Oct 2014 18:53:36 +0200 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org List-ID: To: Laurent Pinchart , linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-sh@vger.kernel.org, Marek Szyprowski , Russell King - ARM Linux , Joonsoo Kim On Thu, Oct 23 2014, Laurent Pinchart wrote: > If activation of the CMA area fails its mutex won't be initialized, > leading to an oops at allocation time when trying to lock the mutex. Fix > this by failing allocation if the area hasn't been successfully actived, > and detect that condition by moving the CMA bitmap allocation after page > block reservation completion. > > Signed-off-by: Laurent Pinchart Cc: # v3.17 Acked-by: Michal Nazarewicz As a matter of fact, this is present in kernels earlier than 3.17 but in the 3.17 the code has been moved from drivers/base/dma-contiguous.c to mm/cma.c so this might require separate stable patch. I can track this and prepare a patch if you want. > --- > mm/cma.c | 17 ++++++----------- > 1 file changed, 6 insertions(+), 11 deletions(-) > > diff --git a/mm/cma.c b/mm/cma.c > index 963bc4a..16c6650 100644 > --- a/mm/cma.c > +++ b/mm/cma.c > @@ -93,11 +93,6 @@ static int __init cma_activate_area(struct cma *cma) > unsigned i =3D cma->count >> pageblock_order; > struct zone *zone; >=20=20 > - cma->bitmap =3D kzalloc(bitmap_size, GFP_KERNEL); > - > - if (!cma->bitmap) > - return -ENOMEM; > - > WARN_ON_ONCE(!pfn_valid(pfn)); > zone =3D page_zone(pfn_to_page(pfn)); >=20=20 > @@ -114,17 +109,17 @@ static int __init cma_activate_area(struct cma *cma) > * to be in the same zone. > */ > if (page_zone(pfn_to_page(pfn)) !=3D zone) > - goto err; > + return -EINVAL; > } > init_cma_reserved_pageblock(pfn_to_page(base_pfn)); > } while (--i); >=20=20 > + cma->bitmap =3D kzalloc(bitmap_size, GFP_KERNEL); > + if (!cma->bitmap) > + return -ENOMEM; > + > mutex_init(&cma->lock); > return 0; > - > -err: > - kfree(cma->bitmap); > - return -EINVAL; > } >=20=20 > static int __init cma_init_reserved_areas(void) > @@ -313,7 +308,7 @@ struct page *cma_alloc(struct cma *cma, int count, un= signed int align) > struct page *page =3D NULL; > int ret; >=20=20 > - if (!cma || !cma->count) > + if (!cma || !cma->count || !cma->bitmap) > return NULL; >=20=20 > pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma, > --=20 > 2.0.4 > --=20 Best regards, _ _ .o. | Liege of Serenely Enlightened Majesty of o' \,=3D./ `o ..o | Computer Science, Micha=C5=82 =E2=80=9Cmina86=E2=80=9D Nazarewicz = (o o) ooo +------ooO--(_)--Ooo-- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org