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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 49660C352A1 for ; Wed, 30 Nov 2022 09:51:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234727AbiK3JvC (ORCPT ); Wed, 30 Nov 2022 04:51:02 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53282 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233824AbiK3JvA (ORCPT ); Wed, 30 Nov 2022 04:51:00 -0500 Received: from mail-pf1-x433.google.com (mail-pf1-x433.google.com [IPv6:2607:f8b0:4864:20::433]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6DAE323E8D for ; Wed, 30 Nov 2022 01:50:59 -0800 (PST) Received: by mail-pf1-x433.google.com with SMTP id 130so16309285pfu.8 for ; Wed, 30 Nov 2022 01:50:59 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=fCDpuFqBTHvf3fXps1nwbiUOUTIG5grHkE4dg45zXiU=; b=BrzfRiAIKgBCwf/1XbC9soyiaZFoKSujRTecLdpKHMQ6JT3GbuZ31zGFA16mTqSSrr AcbsaDC1n/l/b36aCiv23bUtWWab/DRNVtySMyVBBMLGJVSF+GnocEeNPY7FpUiwFlos J2T2JYnB7cihSiB+izdoW56np0eDooJ0hloGrDeM64hdZPGgyE8AbeTbcI0Cp+UlGyky w+kwU4fNc+UzCrvKYmDqX13xJFhTHwsj2FJsarqHOURnI9eE+tAryYe+9NGAZ+9S3F/A gAvA/04B0XDfFerVSA3xnyvSWIAuVY+h/9a1cwdgAOgpKUY8UhbGjfvvW1MfX51uW0wI D7vA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=fCDpuFqBTHvf3fXps1nwbiUOUTIG5grHkE4dg45zXiU=; b=SGPPyn27Jv/TTsbrcZucYn1tVCpiiQ4F5EFLA9lnZ2s9v6/mYoi/Zr+e1RBPXdg6ER /bDsUr9+y3q1vDryIZ/6HBfAGKcjs1RHUbA18oGrZzElvPtjW6HOJH9xf1FdBd3Mv416 Uci6hq3SGG2FSJY4ZZEbl3h7UVJSgJfRhc5fisIjjY6zSutHe3yyaiIar/riV4Yqsgov oOG4yimNxE13T4qZh7sYPSm7iZPt8FjK/5NA8EKYG2eBpn0a44KzMbUr7OIRNVm8ySFX +AsGcGh0hKSTnVQ4971f0d5EkCz4zJhH/BlCJPTalokdksOXd1tw1pi2hG0UyhwX1rGA ij3w== X-Gm-Message-State: ANoB5pmZKJTNUIO2rJZOEoFeR2bg0XAg8YF0X2vHceJCIWNt68GSEo5R CEdueW5noShWFUaJt4u4eJ4= X-Google-Smtp-Source: AA0mqf5MZtBxwaQffNbvd9eCRCcJQb9bmhF7W+k86i7Gt4yWQkn/yUTu1QS9uGzNnbsZN7wiTW32BA== X-Received: by 2002:a62:1586:0:b0:575:f08b:7a9f with SMTP id 128-20020a621586000000b00575f08b7a9fmr780206pfv.60.1669801858805; Wed, 30 Nov 2022 01:50:58 -0800 (PST) Received: from hyeyoo ([114.29.91.56]) by smtp.gmail.com with ESMTPSA id n6-20020a170902d2c600b0017c19d7c89bsm960582plc.269.2022.11.30.01.50.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 30 Nov 2022 01:50:57 -0800 (PST) Date: Wed, 30 Nov 2022 18:50:52 +0900 From: Hyeonggon Yoo <42.hyeyoo@gmail.com> To: Feng Tang Cc: Vlastimil Babka , Marco Elver , Andrew Morton , Oliver Glitta , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Roman Gushchin , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 2/2] mm/slub, kunit: Add a test case for kmalloc redzone check Message-ID: References: <20221130085451.3390992-1-feng.tang@intel.com> <20221130085451.3390992-2-feng.tang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221130085451.3390992-2-feng.tang@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 30, 2022 at 04:54:51PM +0800, Feng Tang wrote: > kmalloc redzone check for slub has been merged, and it's better to add > a kunit case for it, which is inspired by a real-world case as described > in commit 120ee599b5bf ("staging: octeon-usb: prevent memory corruption"): > > " > octeon-hcd will crash the kernel when SLOB is used. This usually happens > after the 18-byte control transfer when a device descriptor is read. > The DMA engine is always transferring full 32-bit words and if the > transfer is shorter, some random garbage appears after the buffer. > The problem is not visible with SLUB since it rounds up the allocations > to word boundary, and the extra bytes will go undetected. > " > > To avoid interrupting the normal functioning of kmalloc caches, a > kmem_cache mimicing kmalloc cache is created with similar flags, and > kmalloc_trace() is used to really test the orig_size and redzone setup. > > Suggested-by: Vlastimil Babka > Signed-off-by: Feng Tang > --- > Changelog: > > since v2: > * only add SLAB_KMALLOC to SLAB_CACHE_FLAGS and SLAB_FLAGS_PERMITTEDa, > and use new wrapper of cache creation(Vlastimil Babka) > > since v1: > * create a new cache mimicing kmalloc cache, reduce dependency > over global slub_debug setting (Vlastimil Babka) > > lib/slub_kunit.c | 22 ++++++++++++++++++++++ > mm/slab.h | 4 +++- > 2 files changed, 25 insertions(+), 1 deletion(-) > > diff --git a/lib/slub_kunit.c b/lib/slub_kunit.c > index 5b0c8e7eb6dc..ff24879e3afe 100644 > --- a/lib/slub_kunit.c > +++ b/lib/slub_kunit.c > @@ -135,6 +135,27 @@ static void test_clobber_redzone_free(struct kunit *test) > kmem_cache_destroy(s); > } > > +static void test_kmalloc_redzone_access(struct kunit *test) > +{ > + struct kmem_cache *s = test_kmem_cache_create("TestSlub_RZ_kmalloc", 32, > + SLAB_KMALLOC|SLAB_STORE_USER|SLAB_RED_ZONE); > + u8 *p = kmalloc_trace(s, GFP_KERNEL, 18); > + > + kasan_disable_current(); > + > + /* Suppress the -Warray-bounds warning */ > + OPTIMIZER_HIDE_VAR(p); > + p[18] = 0xab; > + p[19] = 0xab; > + > + kmem_cache_free(s, p); > + validate_slab_cache(s); > + KUNIT_EXPECT_EQ(test, 2, slab_errors); > + > + kasan_enable_current(); > + kmem_cache_destroy(s); > +} > + > static int test_init(struct kunit *test) > { > slab_errors = 0; > @@ -154,6 +175,7 @@ static struct kunit_case test_cases[] = { > #endif > > KUNIT_CASE(test_clobber_redzone_free), > + KUNIT_CASE(test_kmalloc_redzone_access), > {} > }; > > diff --git a/mm/slab.h b/mm/slab.h > index c71590f3a22b..7cc432969945 100644 > --- a/mm/slab.h > +++ b/mm/slab.h > @@ -344,7 +344,8 @@ static inline slab_flags_t kmem_cache_flags(unsigned int object_size, > SLAB_ACCOUNT) > #elif defined(CONFIG_SLUB) > #define SLAB_CACHE_FLAGS (SLAB_NOLEAKTRACE | SLAB_RECLAIM_ACCOUNT | \ > - SLAB_TEMPORARY | SLAB_ACCOUNT | SLAB_NO_USER_FLAGS) > + SLAB_TEMPORARY | SLAB_ACCOUNT | \ > + SLAB_NO_USER_FLAGS | SLAB_KMALLOC) > #else > #define SLAB_CACHE_FLAGS (SLAB_NOLEAKTRACE) > #endif > @@ -364,6 +365,7 @@ static inline slab_flags_t kmem_cache_flags(unsigned int object_size, > SLAB_RECLAIM_ACCOUNT | \ > SLAB_TEMPORARY | \ > SLAB_ACCOUNT | \ > + SLAB_KMALLOC | \ > SLAB_NO_USER_FLAGS) > > bool __kmem_cache_empty(struct kmem_cache *); > -- > 2.34.1 > Looks good to me. Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> -- Thanks, Hyeonggon