From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751504Ab0BHMyG (ORCPT ); Mon, 8 Feb 2010 07:54:06 -0500 Received: from fg-out-1718.google.com ([72.14.220.153]:57778 "EHLO fg-out-1718.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751241Ab0BHMyC convert rfc822-to-8bit (ORCPT ); Mon, 8 Feb 2010 07:54:02 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type :content-transfer-encoding; b=UBHttWHUJeQLiQGyiFslmrOv9TEVk0CXJlaHgeoocM6MsOv6UaTPWiq+U3NoNH/b9b 4+rlyXvtIpIe1LNWbaKRMlfsC78ndiVAz2Nv/zEwD6ztB3jpVrBTgHjcBPZJwaLlJA8+ GecjgH8R/NdjoA/teGM9JJikfPo4zO6cIYsqI= MIME-Version: 1.0 In-Reply-To: <20100208111624.5387.37948.stgit@pc1117.cambridge.arm.com> References: <20100208111624.5387.37948.stgit@pc1117.cambridge.arm.com> Date: Mon, 8 Feb 2010 14:54:00 +0200 X-Google-Sender-Auth: 3341fee49dc92840 Message-ID: <84144f021002080454j2db78133veda0c50a7eff7e6f@mail.gmail.com> Subject: Re: [PATCH] kmemcheck: Test the full object in kmemcheck_is_obj_initialized() From: Pekka Enberg To: Catalin Marinas Cc: linux-kernel@vger.kernel.org, Vegard Nossum , Andrew Morton , Christian Casteyde Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 8, 2010 at 1:16 PM, Catalin Marinas wrote: > This is a fix for bug #14845 (bugzilla.kernel.org). The > update_checksum() function in mm/kmemleak.c calls > kmemcheck_is_obj_initialised() before scanning an object. When > KMEMCHECK_PARTIAL_OK is enabled, this function returns true. However, > the crc32_le() reads smaller intervals (32-bit) for which > kmemleak_is_obj_initialised() may be false leading to a kmemcheck > warning. > > Note that kmemcheck_is_obj_initialized() is currently only used by > kmemleak before scanning a memory location. > > Signed-off-by: Catalin Marinas > Cc: Andrew Morton > Cc: Christian Casteyde > Cc: Pekka Enberg > Cc: Vegard Nossum Acked-by: Pekka Enberg Andrew, Vegard has been rather quiet lately so do you mind picking up this patch? Alternatively, I can pick it up in slab.git if you so prefer. > --- >  arch/x86/mm/kmemcheck/kmemcheck.c |    2 +- >  arch/x86/mm/kmemcheck/shadow.c    |   16 ++++++++++++++-- >  arch/x86/mm/kmemcheck/shadow.h    |    2 ++ >  3 files changed, 17 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/mm/kmemcheck/kmemcheck.c b/arch/x86/mm/kmemcheck/kmemcheck.c > index 8cc1833..b3b531a 100644 > --- a/arch/x86/mm/kmemcheck/kmemcheck.c > +++ b/arch/x86/mm/kmemcheck/kmemcheck.c > @@ -337,7 +337,7 @@ bool kmemcheck_is_obj_initialized(unsigned long addr, size_t size) >        if (!shadow) >                return true; > > -       status = kmemcheck_shadow_test(shadow, size); > +       status = kmemcheck_shadow_test_all(shadow, size); > >        return status == KMEMCHECK_SHADOW_INITIALIZED; >  } > diff --git a/arch/x86/mm/kmemcheck/shadow.c b/arch/x86/mm/kmemcheck/shadow.c > index 3f66b82..aec1242 100644 > --- a/arch/x86/mm/kmemcheck/shadow.c > +++ b/arch/x86/mm/kmemcheck/shadow.c > @@ -125,12 +125,12 @@ void kmemcheck_mark_initialized_pages(struct page *p, unsigned int n) > >  enum kmemcheck_shadow kmemcheck_shadow_test(void *shadow, unsigned int size) >  { > +#ifdef CONFIG_KMEMCHECK_PARTIAL_OK >        uint8_t *x; >        unsigned int i; > >        x = shadow; > > -#ifdef CONFIG_KMEMCHECK_PARTIAL_OK >        /* >         * Make sure _some_ bytes are initialized. Gcc frequently generates >         * code to access neighboring bytes. > @@ -139,13 +139,25 @@ enum kmemcheck_shadow kmemcheck_shadow_test(void *shadow, unsigned int size) >                if (x[i] == KMEMCHECK_SHADOW_INITIALIZED) >                        return x[i]; >        } > + > +       return x[0]; >  #else > +       return kmemcheck_shadow_test_all(shadow, size); > +#endif > +} > + > +enum kmemcheck_shadow kmemcheck_shadow_test_all(void *shadow, unsigned int size) > +{ > +       uint8_t *x; > +       unsigned int i; > + > +       x = shadow; > + >        /* All bytes must be initialized. */ >        for (i = 0; i < size; ++i) { >                if (x[i] != KMEMCHECK_SHADOW_INITIALIZED) >                        return x[i]; >        } > -#endif > >        return x[0]; >  } > diff --git a/arch/x86/mm/kmemcheck/shadow.h b/arch/x86/mm/kmemcheck/shadow.h > index af46d9a..ff0b2f7 100644 > --- a/arch/x86/mm/kmemcheck/shadow.h > +++ b/arch/x86/mm/kmemcheck/shadow.h > @@ -11,6 +11,8 @@ enum kmemcheck_shadow { >  void *kmemcheck_shadow_lookup(unsigned long address); > >  enum kmemcheck_shadow kmemcheck_shadow_test(void *shadow, unsigned int size); > +enum kmemcheck_shadow kmemcheck_shadow_test_all(void *shadow, > +                                               unsigned int size); >  void kmemcheck_shadow_set(void *shadow, unsigned int size); > >  #endif > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at  http://vger.kernel.org/majordomo-info.html > Please read the FAQ at  http://www.tux.org/lkml/ >