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=-9.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,HTML_MESSAGE,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 66999C433B4 for ; Thu, 1 Apr 2021 10:37:02 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 82CA9610CA for ; Thu, 1 Apr 2021 10:37:01 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 82CA9610CA Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id C7C9B6B0080; Thu, 1 Apr 2021 06:37:00 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C2C2E6B0081; Thu, 1 Apr 2021 06:37:00 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A30CE6B0082; Thu, 1 Apr 2021 06:37:00 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0075.hostedemail.com [216.40.44.75]) by kanga.kvack.org (Postfix) with ESMTP id 772186B0080 for ; Thu, 1 Apr 2021 06:37:00 -0400 (EDT) Received: from smtpin36.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 2E097824999B for ; Thu, 1 Apr 2021 10:37:00 +0000 (UTC) X-FDA: 77983445400.36.99F313B Received: from mail-pf1-f182.google.com (mail-pf1-f182.google.com [209.85.210.182]) by imf01.hostedemail.com (Postfix) with ESMTP id 2C56C5001528 for ; Thu, 1 Apr 2021 10:36:59 +0000 (UTC) Received: by mail-pf1-f182.google.com with SMTP id g15so1189718pfq.3 for ; Thu, 01 Apr 2021 03:36:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=TV0DncucNe+IEOEiD5OpaXlHKPop6d58Ck+3Qgf0jYY=; b=ECSduX5PJ0kSJUNR1IGZBsP0yYNT+MIFIDuxn5csPdUc+Kzwvh1IjJg0v73w8mEmdC XxqGZVkLNCAHd2MYePDxNhp993i86qUwTvERtbEIeBltfLRYGG6Pf4Pal5rkvH3XybCW ynCi8azEyGfu0LjhJcsAajRfYeUZI7Vdn3dcbOmxXj12534hHdF3qLlUoaNXzAEob8rg K4OoxbZvDZ5zYZDmzCYEfZhlLEaPjwlo8Go24tWE7Vob/vJbyQm0i98I+o5wnq8qPbRU 5enC7uGLoRdmYlgv5PG4H0lt6dhdw/yRaQe+TGpUacW+VFPkkSSnsQvzJU2O5oPau2dY UsNw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=TV0DncucNe+IEOEiD5OpaXlHKPop6d58Ck+3Qgf0jYY=; b=Y7y4GkyVZgbUALIeUdz/riegHvwhg982n6e/9aOnkNUCWeCPetv+LKTG0R2xW9azaY i6ZNvkcWIpJtcsIUuUS02OT+6CVktG27jUKAfLRt6CrvOVN693mW8kv8AqEuTgOPzVK2 taQHAiFkze8/2mEZASRy8ceaau4bCm3/UvrtEvLHwr/8e35S/DkdP38vJJtd1D5LSxKF 8HOHWhhX1YGVvLTDV8Qjv6eYy82X/ub0QehONlOBQd2YnAZeXLUQ/OrWMghhAzNJUbgM LpSL3V/W2xhF0ov39j20+Tfha/UtnTg/LhyQAwUWXEdY+aZoscroVToOvTtqADXaEeD8 Abow== X-Gm-Message-State: AOAM531leGcDypX/+nLWC5DihHwHrjki0laBVvlbIaP5Yyzfa50bKcUo 2iJDNyoSq9jk+k5+GF+mUuDf513f842vCqowAoU= X-Google-Smtp-Source: ABdhPJwgI635zELEuXpi6m/AMA5BfnPj1Jm3OPy02AS6UG5T/5xVNufpILe0bkbFO832zhxprvrRrw4vFbln8mBI5d8= X-Received: by 2002:aa7:8a4d:0:b029:211:92f2:658c with SMTP id n13-20020aa78a4d0000b029021192f2658cmr7087362pfa.29.1617273418541; Thu, 01 Apr 2021 03:36:58 -0700 (PDT) MIME-Version: 1.0 References: <20210331085156.5028-1-glittao@gmail.com> In-Reply-To: From: Oliver Glitta Date: Thu, 1 Apr 2021 12:36:47 +0200 Message-ID: Subject: Re: [PATCH v3 1/2] kunit: add a KUnit test for SLUB debugging functionality To: Marco Elver Cc: cl@linux.com, penberg@kernel.org, rientjes@google.com, iamjoonsoo.kim@lge.com, akpm@linux-foundation.org, Vlastimil Babka , linux-kernel@vger.kernel.org, linux-mm@kvack.org, kunit-dev@googlegroups.com Content-Type: multipart/alternative; boundary="0000000000009ded8505bee6cf6c" X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 2C56C5001528 X-Stat-Signature: es34jdobhcxzibowtrmcjd78eecccisb Received-SPF: none (gmail.com>: No applicable sender policy available) receiver=imf01; identity=mailfrom; envelope-from=""; helo=mail-pf1-f182.google.com; client-ip=209.85.210.182 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1617273419-330335 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: --0000000000009ded8505bee6cf6c Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Thank you for your feedback. I will take a look at that. =C5=A1t 1. 4. 2021 o 11:16 Marco Elver nap=C3=ADsal(a): > [Note, if you'd like me to see future versions, please Cc me, otherwise > it's unlikely I see it in time. Also add kunit-dev@googlegroups.com if > perhaps a KUnit dev should have another look, too.] > > On Wed, Mar 31, 2021 at 10:51AM +0200, glittao@gmail.com wrote: > > From: Oliver Glitta > > > > SLUB has resiliency_test() function which is hidden behind #ifdef > > SLUB_RESILIENCY_TEST that is not part of Kconfig, so nobody > > runs it. KUnit should be a proper replacement for it. > > > > Try changing byte in redzone after allocation and changing > > pointer to next free node, first byte, 50th byte and redzone > > byte. Check if validation finds errors. > > > > There are several differences from the original resiliency test: > > Tests create own caches with known state instead of corrupting > > shared kmalloc caches. > > > > The corruption of freepointer uses correct offset, the original > > resiliency test got broken with freepointer changes. > > > > Scratch changing random byte test, because it does not have > > meaning in this form where we need deterministic results. > > > > Add new option CONFIG_SLUB_KUNIT_TEST in Kconfig. > > > > Add a counter field "errors" to struct kmem_cache to count number > > of errors detected in cache. > > > > Silence bug report in SLUB test. Add SLAB_SILENT_ERRORS debug flag. > > Add SLAB_SILENT_ERRORS flag to SLAB_NEVER_MERGE, SLAB_DEBUG_FLAGS, > > SLAB_FLAGS_PERMITTED macros. > > > > Signed-off-by: Oliver Glitta > > --- > > Changes since v2 > > > > Use bit operation & instead of logical && as reported by kernel test > > robot and Dan Carpenter > > > > Changes since v1 > > > > Conversion from kselftest to KUnit test suggested by Marco Elver. > > Error silencing. > > Error counting improvements. > > > > include/linux/slab.h | 2 + > > include/linux/slub_def.h | 2 + > > lib/Kconfig.debug | 5 ++ > > lib/Makefile | 1 + > > lib/test_slub.c | 124 +++++++++++++++++++++++++++++++++++++++ > > mm/slab.h | 7 ++- > > mm/slab_common.c | 2 +- > > mm/slub.c | 64 +++++++++++++------- > > 8 files changed, 184 insertions(+), 23 deletions(-) > > create mode 100644 lib/test_slub.c > > > > diff --git a/include/linux/slab.h b/include/linux/slab.h > > index 7ae604076767..ed1a5a64d028 100644 > > --- a/include/linux/slab.h > > +++ b/include/linux/slab.h > > @@ -25,6 +25,8 @@ > > */ > > /* DEBUG: Perform (expensive) checks on alloc/free */ > > #define SLAB_CONSISTENCY_CHECKS ((slab_flags_t __force)0x00000100= U) > > +/* DEBUG: Silent bug reports */ > > +#define SLAB_SILENT_ERRORS ((slab_flags_t __force)0x00000200U) > > This flag wouldn't be necessary if you do the design using > kunit_resource (see below). > > (But perhaps I missed a conversation that said that this flag is > generally useful, but if so, it should probably be in a separate patch > justifying why it is required beyond the test.) > > > /* DEBUG: Red zone objs in a cache */ > > #define SLAB_RED_ZONE ((slab_flags_t __force)0x00000400= U) > > /* DEBUG: Poison objects */ > > diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h > > index dcde82a4434c..e4b51bb5bb83 100644 > > --- a/include/linux/slub_def.h > > +++ b/include/linux/slub_def.h > > @@ -133,6 +133,8 @@ struct kmem_cache { > > unsigned int usersize; /* Usercopy region size */ > > > > struct kmem_cache_node *node[MAX_NUMNODES]; > > + > > + int errors; /* Number of errors in cache */ > > So, I think it's bad design to add a new field 'errors', just for the > test. This will increase kmem_cache size for all builds, which is > unnecessary. > > Is there use to retrieve 'errors' elsewhere? > > While you could guard this with #ifdef CONFIG_SLUB_DEBUG or so, there's > a better design option if this is just for the KUnit test's benefit: use > kunit_resource. > > The way it'd work is that for each test (you can add a common init > function) you add a named resource, in this case just an 'int' I guess, > that slab would be able to retrieve if this test is being run. > > In the test somewhere, you could add something like this: > > > static struct kunit_resource resource; > static int slab_errors; > > .......... > > static int test_init(struct kunit *test) > { > slab_errors =3D 0; > kunit_add_named_resource(test, NULL, NULL, &resource, > "slab_errors", &slab_errors); > return 0; > } > > ...... tests now check slab_errors ..... > > and then in slub.c you'd have: > > #if IS_ENABLED(CONFIG_KUNIT) > static bool slab_add_kunit_errors(void) > { > struct kunit_resource *resource; > > if (likely(!current->kunit_test)) > return false; > resource =3D kunit_find_named_resource(current->kunit_tes= t, > "slab_errors"); > if (!resource) > return false; > (*(int *)resource->data)++; > kunit_put_resource(resource); > } > #else > static inline bool slab_add_kunit_errors(void) { return false; } > #endif > > And anywhere you want to increase the error count, you'd call > slab_add_kunit_errors(). > > Another benefit of this approach is that if KUnit is disabled, there is > zero overhead and no additional code generated (vs. the current > approach). > > > }; > > > > #ifdef CONFIG_SLUB_CPU_PARTIAL > > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > > index 2779c29d9981..e0dec830c269 100644 > > --- a/lib/Kconfig.debug > > +++ b/lib/Kconfig.debug > > @@ -2371,6 +2371,11 @@ config BITS_TEST > > > > If unsure, say N. > > > > +config SLUB_KUNIT_TEST > > + tristate "KUnit Test for SLUB cache error detection" if > !KUNIT_ALL_TESTS > > + depends on SLUB_DEBUG && KUNIT > > + default KUNIT_ALL_TESTS > > Help text please. > > > + > > config TEST_UDELAY > > tristate "udelay test driver" > > help > > diff --git a/lib/Makefile b/lib/Makefile > > index b5307d3eec1a..e1eb986c0e87 100644 > > --- a/lib/Makefile > > +++ b/lib/Makefile > > @@ -352,5 +352,6 @@ obj-$(CONFIG_LIST_KUNIT_TEST) +=3D list-test.o > > obj-$(CONFIG_LINEAR_RANGES_TEST) +=3D test_linear_ranges.o > > obj-$(CONFIG_BITS_TEST) +=3D test_bits.o > > obj-$(CONFIG_CMDLINE_KUNIT_TEST) +=3D cmdline_kunit.o > > +obj-$(CONFIG_SLUB_KUNIT_TEST) +=3D test_slub.o > > Any reason to not name this slub_kunit.c? This is a new test, and it > could follow the naming convention of the other KUnit tests. > > Some of it is also documented: > https://www.kernel.org/doc/html/latest/dev-tools/kunit/style.html > > > obj-$(CONFIG_GENERIC_LIB_DEVMEM_IS_ALLOWED) +=3D devmem_is_allowed.o > > diff --git a/lib/test_slub.c b/lib/test_slub.c > > new file mode 100644 > > index 000000000000..4f8ea3c7d867 > > --- /dev/null > > +++ b/lib/test_slub.c > > @@ -0,0 +1,124 @@ > > +// SPDX-License-Identifier: GPL-2.0 > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include "../mm/slab.h" > > + > > + > > +static void test_clobber_zone(struct kunit *test) > > +{ > > + struct kmem_cache *s =3D kmem_cache_create("TestSlub_RZ_alloc", 6= 4, > 0, > > + SLAB_RED_ZONE | SLAB_SILENT_ERRORS, NULL)= ; > > + u8 *p =3D kmem_cache_alloc(s, GFP_KERNEL); > > + > > + p[64] =3D 0x12; > > + > > + validate_slab_cache(s); > > + KUNIT_EXPECT_EQ(test, 1, s->errors); > > + > > + kmem_cache_free(s, p); > > + kmem_cache_destroy(s); > > +} > > + > > +static void test_next_pointer(struct kunit *test) > > +{ > > + struct kmem_cache *s =3D kmem_cache_create("TestSlub_next_ptr_fre= e", > 64, 0, > > + SLAB_POISON | SLAB_SILENT_ERRORS, NULL); > > + u8 *p =3D kmem_cache_alloc(s, GFP_KERNEL); > > + unsigned long tmp; > > + unsigned long *ptr_addr; > > + > > + kmem_cache_free(s, p); > > + > > + ptr_addr =3D (unsigned long *)(p + s->offset); > > + tmp =3D *ptr_addr; > > + p[s->offset] =3D 0x12; > > + > > + /* > > + * Expecting two errors. > > + * One for the corrupted freechain and the other one for the wron= g > > + * count of objects in use. > > + */ > > + validate_slab_cache(s); > > + KUNIT_EXPECT_EQ(test, 2, s->errors); > > + > > + /* > > + * Try to repair corrupted freepointer. > > + * Still expecting one error for the wrong count of objects in us= e. > > + */ > > + *ptr_addr =3D tmp; > > + > > + validate_slab_cache(s); > > + KUNIT_EXPECT_EQ(test, 1, s->errors); > > + > > + /* > > + * Previous validation repaired the count of objects in use. > > + * Now expecting no error. > > + */ > > + validate_slab_cache(s); > > + KUNIT_EXPECT_EQ(test, 0, s->errors); > > + > > + kmem_cache_destroy(s); > > +} > > + > > +static void test_first_word(struct kunit *test) > > +{ > > + struct kmem_cache *s =3D kmem_cache_create("TestSlub_1th_word_fre= e", > 64, 0, > > + SLAB_POISON | SLAB_SILENT_ERRORS, NULL); > > + u8 *p =3D kmem_cache_alloc(s, GFP_KERNEL); > > + > > + kmem_cache_free(s, p); > > + *p =3D 0x78; > > + > > + validate_slab_cache(s); > > + KUNIT_EXPECT_EQ(test, 1, s->errors); > > + > > + kmem_cache_destroy(s); > > +} > > + > > +static void test_clobber_50th_byte(struct kunit *test) > > +{ > > + struct kmem_cache *s =3D > kmem_cache_create("TestSlub_50th_word_free", 64, 0, > > + SLAB_POISON | SLAB_SILENT_ERRORS, NULL); > > + u8 *p =3D kmem_cache_alloc(s, GFP_KERNEL); > > + > > + kmem_cache_free(s, p); > > + p[50] =3D 0x9a; > > + > > + validate_slab_cache(s); > > + KUNIT_EXPECT_EQ(test, 1, s->errors); > > + kmem_cache_destroy(s); > > +} > > + > > +static void test_clobber_redzone_free(struct kunit *test) > > +{ > > + struct kmem_cache *s =3D kmem_cache_create("TestSlub_RZ_free", 64= , 0, > > + SLAB_RED_ZONE | SLAB_SILENT_ERRORS, NULL)= ; > > + u8 *p =3D kmem_cache_alloc(s, GFP_KERNEL); > > + > > + kmem_cache_free(s, p); > > + p[64] =3D 0xab; > > + > > + validate_slab_cache(s); > > + KUNIT_EXPECT_EQ(test, 1, s->errors); > > + kmem_cache_destroy(s); > > +} > > + > > +static struct kunit_case test_cases[] =3D { > > + KUNIT_CASE(test_clobber_zone), > > + KUNIT_CASE(test_next_pointer), > > + KUNIT_CASE(test_first_word), > > + KUNIT_CASE(test_clobber_50th_byte), > > + KUNIT_CASE(test_clobber_redzone_free), > > + {} > > +}; > > + > > +static struct kunit_suite test_suite =3D { > > + .name =3D "slub_test", > > + .test_cases =3D test_cases, > > Here you could add a > > .init =3D test_init, > > or so, if you go with the kunit_resource design. > > > +}; > > +kunit_test_suite(test_suite); > > + > > +MODULE_LICENSE("GPL"); > > diff --git a/mm/slab.h b/mm/slab.h > > index 076582f58f68..382507b6cab9 100644 > > --- a/mm/slab.h > > +++ b/mm/slab.h > > @@ -134,7 +134,8 @@ static inline slab_flags_t kmem_cache_flags(unsigne= d > int object_size, > > #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USE= R) > > #elif defined(CONFIG_SLUB_DEBUG) > > #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USE= R > | \ > > - SLAB_TRACE | SLAB_CONSISTENCY_CHECKS) > > + SLAB_TRACE | SLAB_CONSISTENCY_CHECKS | \ > > + SLAB_SILENT_ERRORS) > > #else > > #define SLAB_DEBUG_FLAGS (0) > > #endif > > @@ -164,7 +165,8 @@ static inline slab_flags_t kmem_cache_flags(unsigne= d > int object_size, > > SLAB_NOLEAKTRACE | \ > > SLAB_RECLAIM_ACCOUNT | \ > > SLAB_TEMPORARY | \ > > - SLAB_ACCOUNT) > > + SLAB_ACCOUNT | \ > > + SLAB_SILENT_ERRORS) > > > > bool __kmem_cache_empty(struct kmem_cache *); > > int __kmem_cache_shutdown(struct kmem_cache *); > > @@ -215,6 +217,7 @@ DECLARE_STATIC_KEY_TRUE(slub_debug_enabled); > > DECLARE_STATIC_KEY_FALSE(slub_debug_enabled); > > #endif > > extern void print_tracking(struct kmem_cache *s, void *object); > > +long validate_slab_cache(struct kmem_cache *s); > > #else > > static inline void print_tracking(struct kmem_cache *s, void *object) > > { > > diff --git a/mm/slab_common.c b/mm/slab_common.c > > index 88e833986332..239c9095e7ea 100644 > > --- a/mm/slab_common.c > > +++ b/mm/slab_common.c > > @@ -55,7 +55,7 @@ static DECLARE_WORK(slab_caches_to_rcu_destroy_work, > > */ > > #define SLAB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USE= R > | \ > > SLAB_TRACE | SLAB_TYPESAFE_BY_RCU | SLAB_NOLEAKTRACE | \ > > - SLAB_FAILSLAB | kasan_never_merge()) > > + SLAB_FAILSLAB | SLAB_SILENT_ERRORS | kasan_never_merge()) > > > > #define SLAB_MERGE_SAME (SLAB_RECLAIM_ACCOUNT | SLAB_CACHE_DMA | \ > > SLAB_CACHE_DMA32 | SLAB_ACCOUNT) > > diff --git a/mm/slub.c b/mm/slub.c > > index 3021ce9bf1b3..7083e89432d0 100644 > > --- a/mm/slub.c > > +++ b/mm/slub.c > > @@ -673,14 +673,16 @@ static void slab_bug(struct kmem_cache *s, char > *fmt, ...) > > > > static void slab_fix(struct kmem_cache *s, char *fmt, ...) > > { > > - struct va_format vaf; > > - va_list args; > > - > > - va_start(args, fmt); > > - vaf.fmt =3D fmt; > > - vaf.va =3D &args; > > - pr_err("FIX %s: %pV\n", s->name, &vaf); > > - va_end(args); > > + if (!(s->flags & SLAB_SILENT_ERRORS)) { > > This style of guarding causes lots of line diffs. > > Instead, if the whole function is to be skipped, please prefer: > > if (skip_things_if_true) > return; > > instead of > > if (!skip_things_if_true) { > ... > } > > here and everywhere else. > > Specifically, for the kunit_resource design, this would simply become: > > if (slab_add_kunit_errors()) > return; > > Meaning that whenever a KUnit test has a resource "slab_errors", no > messages are printed -- otherwise it'll always print a message. > > > + struct va_format vaf; > > + va_list args; > > + > > + va_start(args, fmt); > > + vaf.fmt =3D fmt; > > + vaf.va =3D &args; > > + pr_err("FIX %s: %pV\n", s->name, &vaf); > > + va_end(args); > > + } > > } > > > > static bool freelist_corrupted(struct kmem_cache *s, struct page *page= , > > @@ -739,8 +741,10 @@ static void print_trailer(struct kmem_cache *s, > struct page *page, u8 *p) > > void object_err(struct kmem_cache *s, struct page *page, > > u8 *object, char *reason) > > { > > - slab_bug(s, "%s", reason); > > - print_trailer(s, page, object); > > + if (!(s->flags & SLAB_SILENT_ERRORS)) { > > + slab_bug(s, "%s", reason); > > + print_trailer(s, page, object); > > + } > > } > > > > static __printf(3, 4) void slab_err(struct kmem_cache *s, struct page > *page, > > @@ -752,9 +756,11 @@ static __printf(3, 4) void slab_err(struct > kmem_cache *s, struct page *page, > > va_start(args, fmt); > > vsnprintf(buf, sizeof(buf), fmt, args); > > va_end(args); > > - slab_bug(s, "%s", buf); > > - print_page_info(page); > > - dump_stack(); > > + if (!(s->flags & SLAB_SILENT_ERRORS)) { > > + slab_bug(s, "%s", buf); > > + print_page_info(page); > > + dump_stack(); > > + } > > } > > > > static void init_object(struct kmem_cache *s, void *object, u8 val) > > @@ -798,11 +804,13 @@ static int check_bytes_and_report(struct > kmem_cache *s, struct page *page, > > while (end > fault && end[-1] =3D=3D value) > > end--; > > > > - slab_bug(s, "%s overwritten", what); > > - pr_err("INFO: 0x%p-0x%p @offset=3D%tu. First byte 0x%x instead of > 0x%x\n", > > + if (!(s->flags & SLAB_SILENT_ERRORS)) { > > + slab_bug(s, "%s overwritten", what); > > + pr_err("INFO: 0x%p-0x%p @offset=3D%tu. First byte 0x%x > instead of 0x%x\n", > > fault, end - 1, fault - addr, > > fault[0], value); > > - print_trailer(s, page, object); > > + print_trailer(s, page, object); > > + } > > > > restore_bytes(s, what, value, fault, end); > > return 0; > > @@ -964,6 +972,7 @@ static int check_slab(struct kmem_cache *s, struct > page *page) > > > > if (!PageSlab(page)) { > > slab_err(s, page, "Not a valid slab page"); > > + s->errors +=3D 1; > > So to me it looks like errors is set whenever there's a slab_err() or > slab_fix() call. So why not move setting that an error occurred into > those functions? > > > return 0; > > } > > > > @@ -971,11 +980,13 @@ static int check_slab(struct kmem_cache *s, struc= t > page *page) > > if (page->objects > maxobj) { > > slab_err(s, page, "objects %u > max %u", > > page->objects, maxobj); > > + s->errors +=3D 1; > > return 0; > > } > > if (page->inuse > page->objects) { > > slab_err(s, page, "inuse %u > max %u", > > page->inuse, page->objects); > > + s->errors +=3D 1; > > return 0; > > } > > /* Slab_pad_check fixes things up after itself */ > > @@ -1008,8 +1019,10 @@ static int on_freelist(struct kmem_cache *s, > struct page *page, void *search) > > page->freelist =3D NULL; > > page->inuse =3D page->objects; > > slab_fix(s, "Freelist cleared"); > > + s->errors +=3D 1; > > return 0; > > } > > + s->errors +=3D 1; > > break; > > } > > object =3D fp; > > @@ -1026,12 +1039,14 @@ static int on_freelist(struct kmem_cache *s, > struct page *page, void *search) > > page->objects, max_objects); > > page->objects =3D max_objects; > > slab_fix(s, "Number of objects adjusted."); > > + s->errors +=3D 1; > > } > > if (page->inuse !=3D page->objects - nr) { > > slab_err(s, page, "Wrong object count. Counter is %d but > counted were %d", > > page->inuse, page->objects - nr); > > page->inuse =3D page->objects - nr; > > slab_fix(s, "Object count adjusted."); > > + s->errors +=3D 1; > > } > > return search =3D=3D NULL; > > } > > @@ -4629,8 +4644,10 @@ static void validate_slab(struct kmem_cache *s, > struct page *page) > > u8 val =3D test_bit(__obj_to_index(s, addr, p), map) ? > > SLUB_RED_INACTIVE : SLUB_RED_ACTIVE; > > > > - if (!check_object(s, page, p, val)) > > + if (!check_object(s, page, p, val)) { > > + s->errors +=3D 1; > > break; > > + } > > } > > put_map(map); > > unlock: > > @@ -4650,9 +4667,11 @@ static int validate_slab_node(struct kmem_cache > *s, > > validate_slab(s, page); > > count++; > > } > > - if (count !=3D n->nr_partial) > > + if (count !=3D n->nr_partial) { > > pr_err("SLUB %s: %ld partial slabs counted but > counter=3D%ld\n", > > s->name, count, n->nr_partial); > > + s->errors +=3D 1; > > + } > > > > if (!(s->flags & SLAB_STORE_USER)) > > goto out; > > @@ -4661,20 +4680,23 @@ static int validate_slab_node(struct kmem_cache > *s, > > validate_slab(s, page); > > count++; > > } > > - if (count !=3D atomic_long_read(&n->nr_slabs)) > > + if (count !=3D atomic_long_read(&n->nr_slabs)) { > > pr_err("SLUB: %s %ld slabs counted but counter=3D%ld\n", > > s->name, count, atomic_long_read(&n->nr_slabs)); > > + s->errors +=3D 1; > > I think these here are a few cases where there's no slab_err() or > slab_fix() call, and open coding setting errors is still required... > > > + } > > > > out: > > spin_unlock_irqrestore(&n->list_lock, flags); > > return count; > > } > > > > -static long validate_slab_cache(struct kmem_cache *s) > > +long validate_slab_cache(struct kmem_cache *s) > > { > > int node; > > unsigned long count =3D 0; > > struct kmem_cache_node *n; > > + s->errors =3D 0; > > This would also go away if you use the kunit_resource design. I also > think it's better if the test fully controls 'slab_errors', and it isn't > reset by this function. > > > flush_all(s); > > for_each_kmem_cache_node(s, node, n) > > @@ -4682,6 +4704,8 @@ static long validate_slab_cache(struct kmem_cache > *s) > > > > return count; > > } > > +EXPORT_SYMBOL(validate_slab_cache); > > + > > /* > > * Generate lists of code addresses where slabcache objects are > allocated > > * and freed. > > -- > > 2.17.1 > --0000000000009ded8505bee6cf6c Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Thank you for your feedback. I will take a look at th= at.

=C5=A1t 1. 4. 2021 o=C2=A011:16 Marco Elver <elver@google.com> nap=C3=ADsal(a):
[Note, if you'd like me= to see future versions, please Cc me, otherwise
it's unlikely I see it in time. Also add kunit-dev@googlegroups.com if
perhaps a KUnit dev should have another look, too.]

On Wed, Mar 31, 2021 at 10:51AM +0200, glittao@gmail.com wrote:
> From: Oliver Glitta <glittao@gmail.com>
>
> SLUB has resiliency_test() function which is hidden behind #ifdef
> SLUB_RESILIENCY_TEST that is not part of Kconfig, so nobody
> runs it. KUnit should be a proper replacement for it.
>
> Try changing byte in redzone after allocation and changing
> pointer to next free node, first byte, 50th byte and redzone
> byte. Check if validation finds errors.
>
> There are several differences from the original resiliency test:
> Tests create own caches with known state instead of corrupting
> shared kmalloc caches.
>
> The corruption of freepointer uses correct offset, the original
> resiliency test got broken with freepointer changes.
>
> Scratch changing random byte test, because it does not have
> meaning in this form where we need deterministic results.
>
> Add new option CONFIG_SLUB_KUNIT_TEST in Kconfig.
>
> Add a counter field "errors" to struct kmem_cache to count n= umber
> of errors detected in cache.
>
> Silence bug report in SLUB test. Add SLAB_SILENT_ERRORS debug flag. > Add SLAB_SILENT_ERRORS flag to SLAB_NEVER_MERGE, SLAB_DEBUG_FLAGS,
> SLAB_FLAGS_PERMITTED macros.
>
> Signed-off-by: Oliver Glitta <glittao@gmail.com>
> ---
> Changes since v2
>
> Use bit operation & instead of logical && as reported by k= ernel test
> robot and Dan Carpenter
>
> Changes since v1
>
> Conversion from kselftest to KUnit test suggested by Marco Elver.
> Error silencing.
> Error counting improvements.
>
>=C2=A0 include/linux/slab.h=C2=A0 =C2=A0 =C2=A0|=C2=A0 =C2=A02 +
>=C2=A0 include/linux/slub_def.h |=C2=A0 =C2=A02 +
>=C2=A0 lib/Kconfig.debug=C2=A0 =C2=A0 =C2=A0 =C2=A0 |=C2=A0 =C2=A05 ++<= br> >=C2=A0 lib/Makefile=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0|=C2= =A0 =C2=A01 +
>=C2=A0 lib/test_slub.c=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 | 124 ++++++++= +++++++++++++++++++++++++++++++
>=C2=A0 mm/slab.h=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0= |=C2=A0 =C2=A07 ++-
>=C2=A0 mm/slab_common.c=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0|=C2=A0 =C2=A0= 2 +-
>=C2=A0 mm/slub.c=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0= |=C2=A0 64 +++++++++++++-------
>=C2=A0 8 files changed, 184 insertions(+), 23 deletions(-)
>=C2=A0 create mode 100644 lib/test_slub.c
>
> diff --git a/include/linux/slab.h b/include/linux/slab.h
> index 7ae604076767..ed1a5a64d028 100644
> --- a/include/linux/slab.h
> +++ b/include/linux/slab.h
> @@ -25,6 +25,8 @@
>=C2=A0 =C2=A0*/
>=C2=A0 /* DEBUG: Perform (expensive) checks on alloc/free */
>=C2=A0 #define SLAB_CONSISTENCY_CHECKS=C2=A0 =C2=A0 =C2=A0 ((slab_flags= _t __force)0x00000100U)
> +/* DEBUG: Silent bug reports */
> +#define SLAB_SILENT_ERRORS=C2=A0 =C2=A0((slab_flags_t __force)0x00000= 200U)

This flag wouldn't be necessary if you do the design using
kunit_resource (see below).

(But perhaps I missed a conversation that said that this flag is
generally useful, but if so, it should probably be in a separate patch
justifying why it is required beyond the test.)

>=C2=A0 /* DEBUG: Red zone objs in a cache */
>=C2=A0 #define SLAB_RED_ZONE=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 ((slab_flags_t __force)0x00000400U)
>=C2=A0 /* DEBUG: Poison objects */
> diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
> index dcde82a4434c..e4b51bb5bb83 100644
> --- a/include/linux/slub_def.h
> +++ b/include/linux/slub_def.h
> @@ -133,6 +133,8 @@ struct kmem_cache {
>=C2=A0 =C2=A0 =C2=A0 =C2=A0unsigned int usersize;=C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 /* Usercopy region size */
>=C2=A0
>=C2=A0 =C2=A0 =C2=A0 =C2=A0struct kmem_cache_node *node[MAX_NUMNODES];<= br> > +
> +=C2=A0 =C2=A0 =C2=A0int errors;=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0/* Number of errors in cache */

So, I think it's bad design to add a new field 'errors', just f= or the
test. This will increase kmem_cache size for all builds, which is
unnecessary.

Is there use to retrieve 'errors' elsewhere?

While you could guard this with #ifdef CONFIG_SLUB_DEBUG or so, there's=
a better design option if this is just for the KUnit test's benefit: us= e
kunit_resource.

The way it'd work is that for each test (you can add a common init
function) you add a named resource, in this case just an 'int' I gu= ess,
that slab would be able to retrieve if this test is being run.

In the test somewhere, you could add something like this:


=C2=A0 =C2=A0 =C2=A0 =C2=A0 static struct kunit_resource resource;
=C2=A0 =C2=A0 =C2=A0 =C2=A0 static int slab_errors;

=C2=A0 =C2=A0 =C2=A0 =C2=A0 ..........

=C2=A0 =C2=A0 =C2=A0 =C2=A0 static int test_init(struct kunit *test)
=C2=A0 =C2=A0 =C2=A0 =C2=A0 {
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 slab_errors =3D 0;<= br> =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 kunit_add_named_res= ource(test, NULL, NULL, &resource,
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0&q= uot;slab_errors", &slab_errors);
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 return 0;
=C2=A0 =C2=A0 =C2=A0 =C2=A0 }

=C2=A0 =C2=A0 =C2=A0 =C2=A0 ...... tests now check slab_errors .....

and then in slub.c you'd have:

=C2=A0 =C2=A0 =C2=A0 =C2=A0 #if IS_ENABLED(CONFIG_KUNIT)
=C2=A0 =C2=A0 =C2=A0 =C2=A0 static bool slab_add_kunit_errors(void)
=C2=A0 =C2=A0 =C2=A0 =C2=A0 {
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 struct kunit_resour= ce *resource;

=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 if (likely(!current= ->kunit_test))
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 return false;
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 resource =3D kunit_= find_named_resource(current->kunit_test, "slab_errors");
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 if (!resource)
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 return false;
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 (*(int *)resource-&= gt;data)++;
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 kunit_put_resource(= resource);
=C2=A0 =C2=A0 =C2=A0 =C2=A0 }
=C2=A0 =C2=A0 =C2=A0 =C2=A0 #else
=C2=A0 =C2=A0 =C2=A0 =C2=A0 static inline bool slab_add_kunit_errors(void) = { return false; }
=C2=A0 =C2=A0 =C2=A0 =C2=A0 #endif

And anywhere you want to increase the error count, you'd call
slab_add_kunit_errors().

Another benefit of this approach is that if KUnit is disabled, there is
zero overhead and no additional code generated (vs. the current
approach).

>=C2=A0 };
>=C2=A0
>=C2=A0 #ifdef CONFIG_SLUB_CPU_PARTIAL
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index 2779c29d9981..e0dec830c269 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -2371,6 +2371,11 @@ config BITS_TEST
>=C2=A0
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0If unsure, say N.
>=C2=A0
> +config SLUB_KUNIT_TEST
> +=C2=A0 =C2=A0 =C2=A0tristate "KUnit Test for SLUB cache error de= tection" if !KUNIT_ALL_TESTS
> +=C2=A0 =C2=A0 =C2=A0depends on SLUB_DEBUG && KUNIT
> +=C2=A0 =C2=A0 =C2=A0default KUNIT_ALL_TESTS

Help text please.

> +
>=C2=A0 config TEST_UDELAY
>=C2=A0 =C2=A0 =C2=A0 =C2=A0tristate "udelay test driver"
>=C2=A0 =C2=A0 =C2=A0 =C2=A0help
> diff --git a/lib/Makefile b/lib/Makefile
> index b5307d3eec1a..e1eb986c0e87 100644
> --- a/lib/Makefile
> +++ b/lib/Makefile
> @@ -352,5 +352,6 @@ obj-$(CONFIG_LIST_KUNIT_TEST) +=3D list-test.o
>=C2=A0 obj-$(CONFIG_LINEAR_RANGES_TEST) +=3D test_linear_ranges.o
>=C2=A0 obj-$(CONFIG_BITS_TEST) +=3D test_bits.o
>=C2=A0 obj-$(CONFIG_CMDLINE_KUNIT_TEST) +=3D cmdline_kunit.o
> +obj-$(CONFIG_SLUB_KUNIT_TEST) +=3D test_slub.o

Any reason to not name this slub_kunit.c? This is a new test, and it
could follow the naming convention of the other KUnit tests.

Some of it is also documented:
https://www.kernel.org/doc/html/lat= est/dev-tools/kunit/style.html

>=C2=A0 obj-$(CONFIG_GENERIC_LIB_DEVMEM_IS_ALLOWED) +=3D devmem_is_allow= ed.o
> diff --git a/lib/test_slub.c b/lib/test_slub.c
> new file mode 100644
> index 000000000000..4f8ea3c7d867
> --- /dev/null
> +++ b/lib/test_slub.c
> @@ -0,0 +1,124 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#include <kunit/test.h>
> +#include <linux/mm.h>
> +#include <linux/slab.h>
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +#include "../mm/slab.h"
> +
> +
> +static void test_clobber_zone(struct kunit *test)
> +{
> +=C2=A0 =C2=A0 =C2=A0struct kmem_cache *s =3D kmem_cache_create("= TestSlub_RZ_alloc", 64, 0,
> +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0= =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0SLAB_RED_ZONE | SLAB_SILENT_ERRORS, NULL= );
> +=C2=A0 =C2=A0 =C2=A0u8 *p =3D kmem_cache_alloc(s, GFP_KERNEL);
> +
> +=C2=A0 =C2=A0 =C2=A0p[64] =3D 0x12;
> +
> +=C2=A0 =C2=A0 =C2=A0validate_slab_cache(s);
> +=C2=A0 =C2=A0 =C2=A0KUNIT_EXPECT_EQ(test, 1, s->errors);
> +
> +=C2=A0 =C2=A0 =C2=A0kmem_cache_free(s, p);
> +=C2=A0 =C2=A0 =C2=A0kmem_cache_destroy(s);
> +}
> +
> +static void test_next_pointer(struct kunit *test)
> +{
> +=C2=A0 =C2=A0 =C2=A0struct kmem_cache *s =3D kmem_cache_create("= TestSlub_next_ptr_free", 64, 0,
> +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0= =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0SLAB_POISON | SLAB_SILENT_ERRORS, NULL);=
> +=C2=A0 =C2=A0 =C2=A0u8 *p =3D kmem_cache_alloc(s, GFP_KERNEL);
> +=C2=A0 =C2=A0 =C2=A0unsigned long tmp;
> +=C2=A0 =C2=A0 =C2=A0unsigned long *ptr_addr;
> +
> +=C2=A0 =C2=A0 =C2=A0kmem_cache_free(s, p);
> +
> +=C2=A0 =C2=A0 =C2=A0ptr_addr =3D (unsigned long *)(p + s->offset);=
> +=C2=A0 =C2=A0 =C2=A0tmp =3D *ptr_addr;
> +=C2=A0 =C2=A0 =C2=A0p[s->offset] =3D 0x12;
> +
> +=C2=A0 =C2=A0 =C2=A0/*
> +=C2=A0 =C2=A0 =C2=A0 * Expecting two errors.
> +=C2=A0 =C2=A0 =C2=A0 * One for the corrupted freechain and the other = one for the wrong
> +=C2=A0 =C2=A0 =C2=A0 * count of objects in use.
> +=C2=A0 =C2=A0 =C2=A0 */
> +=C2=A0 =C2=A0 =C2=A0validate_slab_cache(s);
> +=C2=A0 =C2=A0 =C2=A0KUNIT_EXPECT_EQ(test, 2, s->errors);
> +
> +=C2=A0 =C2=A0 =C2=A0/*
> +=C2=A0 =C2=A0 =C2=A0 * Try to repair corrupted freepointer.
> +=C2=A0 =C2=A0 =C2=A0 * Still expecting one error for the wrong count = of objects in use.
> +=C2=A0 =C2=A0 =C2=A0 */
> +=C2=A0 =C2=A0 =C2=A0*ptr_addr =3D tmp;
> +
> +=C2=A0 =C2=A0 =C2=A0validate_slab_cache(s);
> +=C2=A0 =C2=A0 =C2=A0KUNIT_EXPECT_EQ(test, 1, s->errors);
> +
> +=C2=A0 =C2=A0 =C2=A0/*
> +=C2=A0 =C2=A0 =C2=A0 * Previous validation repaired the count of obje= cts in use.
> +=C2=A0 =C2=A0 =C2=A0 * Now expecting no error.
> +=C2=A0 =C2=A0 =C2=A0 */
> +=C2=A0 =C2=A0 =C2=A0validate_slab_cache(s);
> +=C2=A0 =C2=A0 =C2=A0KUNIT_EXPECT_EQ(test, 0, s->errors);
> +
> +=C2=A0 =C2=A0 =C2=A0kmem_cache_destroy(s);
> +}
> +
> +static void test_first_word(struct kunit *test)
> +{
> +=C2=A0 =C2=A0 =C2=A0struct kmem_cache *s =3D kmem_cache_create("= TestSlub_1th_word_free", 64, 0,
> +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0= =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0SLAB_POISON | SLAB_SILENT_ERRORS, NULL);=
> +=C2=A0 =C2=A0 =C2=A0u8 *p =3D kmem_cache_alloc(s, GFP_KERNEL);
> +
> +=C2=A0 =C2=A0 =C2=A0kmem_cache_free(s, p);
> +=C2=A0 =C2=A0 =C2=A0*p =3D 0x78;
> +
> +=C2=A0 =C2=A0 =C2=A0validate_slab_cache(s);
> +=C2=A0 =C2=A0 =C2=A0KUNIT_EXPECT_EQ(test, 1, s->errors);
> +
> +=C2=A0 =C2=A0 =C2=A0kmem_cache_destroy(s);
> +}
> +
> +static void test_clobber_50th_byte(struct kunit *test)
> +{
> +=C2=A0 =C2=A0 =C2=A0struct kmem_cache *s =3D kmem_cache_create("= TestSlub_50th_word_free", 64, 0,
> +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0= =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0SLAB_POISON | SLAB_SILENT_ERRORS, NULL);=
> +=C2=A0 =C2=A0 =C2=A0u8 *p =3D kmem_cache_alloc(s, GFP_KERNEL);
> +
> +=C2=A0 =C2=A0 =C2=A0kmem_cache_free(s, p);
> +=C2=A0 =C2=A0 =C2=A0p[50] =3D 0x9a;
> +
> +=C2=A0 =C2=A0 =C2=A0validate_slab_cache(s);
> +=C2=A0 =C2=A0 =C2=A0KUNIT_EXPECT_EQ(test, 1, s->errors);
> +=C2=A0 =C2=A0 =C2=A0kmem_cache_destroy(s);
> +}
> +
> +static void test_clobber_redzone_free(struct kunit *test)
> +{
> +=C2=A0 =C2=A0 =C2=A0struct kmem_cache *s =3D kmem_cache_create("= TestSlub_RZ_free", 64, 0,
> +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0= =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0SLAB_RED_ZONE | SLAB_SILENT_ERRORS, NULL= );
> +=C2=A0 =C2=A0 =C2=A0u8 *p =3D kmem_cache_alloc(s, GFP_KERNEL);
> +
> +=C2=A0 =C2=A0 =C2=A0kmem_cache_free(s, p);
> +=C2=A0 =C2=A0 =C2=A0p[64] =3D 0xab;
> +
> +=C2=A0 =C2=A0 =C2=A0validate_slab_cache(s);
> +=C2=A0 =C2=A0 =C2=A0KUNIT_EXPECT_EQ(test, 1, s->errors);
> +=C2=A0 =C2=A0 =C2=A0kmem_cache_destroy(s);
> +}
> +
> +static struct kunit_case test_cases[] =3D {
> +=C2=A0 =C2=A0 =C2=A0KUNIT_CASE(test_clobber_zone),
> +=C2=A0 =C2=A0 =C2=A0KUNIT_CASE(test_next_pointer),
> +=C2=A0 =C2=A0 =C2=A0KUNIT_CASE(test_first_word),
> +=C2=A0 =C2=A0 =C2=A0KUNIT_CASE(test_clobber_50th_byte),
> +=C2=A0 =C2=A0 =C2=A0KUNIT_CASE(test_clobber_redzone_free),
> +=C2=A0 =C2=A0 =C2=A0{}
> +};
> +
> +static struct kunit_suite test_suite =3D {
> +=C2=A0 =C2=A0 =C2=A0.name =3D "slub_test",
> +=C2=A0 =C2=A0 =C2=A0.test_cases =3D test_cases,

Here you could add a

=C2=A0 =C2=A0 =C2=A0 =C2=A0 .init =3D test_init,

or so, if you go with the kunit_resource design.

> +};
> +kunit_test_suite(test_suite);
> +
> +MODULE_LICENSE("GPL");
> diff --git a/mm/slab.h b/mm/slab.h
> index 076582f58f68..382507b6cab9 100644
> --- a/mm/slab.h
> +++ b/mm/slab.h
> @@ -134,7 +134,8 @@ static inline slab_flags_t kmem_cache_flags(unsign= ed int object_size,
>=C2=A0 #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STO= RE_USER)
>=C2=A0 #elif defined(CONFIG_SLUB_DEBUG)
>=C2=A0 #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STO= RE_USER | \
> -=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0= =C2=A0 =C2=A0SLAB_TRACE | SLAB_CONSISTENCY_CHECKS)
> +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0= =C2=A0 =C2=A0SLAB_TRACE | SLAB_CONSISTENCY_CHECKS | \
> +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0= =C2=A0 =C2=A0SLAB_SILENT_ERRORS)
>=C2=A0 #else
>=C2=A0 #define SLAB_DEBUG_FLAGS (0)
>=C2=A0 #endif
> @@ -164,7 +165,8 @@ static inline slab_flags_t kmem_cache_flags(unsign= ed int object_size,
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0SLAB_NOLEAKTRACE | \
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0SLAB_RECLAIM_ACCOUNT | \
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0SLAB_TEMPORARY | \
> -=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0= =C2=A0 =C2=A0 =C2=A0 =C2=A0SLAB_ACCOUNT)
> +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0= =C2=A0 =C2=A0 =C2=A0 =C2=A0SLAB_ACCOUNT | \
> +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0= =C2=A0 =C2=A0 =C2=A0 =C2=A0SLAB_SILENT_ERRORS)
>=C2=A0
>=C2=A0 bool __kmem_cache_empty(struct kmem_cache *);
>=C2=A0 int __kmem_cache_shutdown(struct kmem_cache *);
> @@ -215,6 +217,7 @@ DECLARE_STATIC_KEY_TRUE(slub_debug_enabled);
>=C2=A0 DECLARE_STATIC_KEY_FALSE(slub_debug_enabled);
>=C2=A0 #endif
>=C2=A0 extern void print_tracking(struct kmem_cache *s, void *object);<= br> > +long validate_slab_cache(struct kmem_cache *s);
>=C2=A0 #else
>=C2=A0 static inline void print_tracking(struct kmem_cache *s, void *ob= ject)
>=C2=A0 {
> diff --git a/mm/slab_common.c b/mm/slab_common.c
> index 88e833986332..239c9095e7ea 100644
> --- a/mm/slab_common.c
> +++ b/mm/slab_common.c
> @@ -55,7 +55,7 @@ static DECLARE_WORK(slab_caches_to_rcu_destroy_work,=
>=C2=A0 =C2=A0*/
>=C2=A0 #define SLAB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STO= RE_USER | \
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0SLAB_TRACE | SLA= B_TYPESAFE_BY_RCU | SLAB_NOLEAKTRACE | \
> -=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0SLAB_FAILSLAB | kasan= _never_merge())
> +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0SLAB_FAILSLAB | SLAB_= SILENT_ERRORS | kasan_never_merge())
>=C2=A0
>=C2=A0 #define SLAB_MERGE_SAME (SLAB_RECLAIM_ACCOUNT | SLAB_CACHE_DMA |= \
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 SLAB_CACHE_DMA32 | SLAB_ACCOUNT)
> diff --git a/mm/slub.c b/mm/slub.c
> index 3021ce9bf1b3..7083e89432d0 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -673,14 +673,16 @@ static void slab_bug(struct kmem_cache *s, char = *fmt, ...)
>=C2=A0
>=C2=A0 static void slab_fix(struct kmem_cache *s, char *fmt, ...)
>=C2=A0 {
> -=C2=A0 =C2=A0 =C2=A0struct va_format vaf;
> -=C2=A0 =C2=A0 =C2=A0va_list args;
> -
> -=C2=A0 =C2=A0 =C2=A0va_start(args, fmt);
> -=C2=A0 =C2=A0 =C2=A0vaf.fmt =3D fmt;
> -=C2=A0 =C2=A0 =C2=A0vaf.va =3D &args;
> -=C2=A0 =C2=A0 =C2=A0pr_err("FIX %s: %pV\n", s->name, &am= p;vaf);
> -=C2=A0 =C2=A0 =C2=A0va_end(args);
> +=C2=A0 =C2=A0 =C2=A0if (!(s->flags & SLAB_SILENT_ERRORS)) {
This style of guarding causes lots of line diffs.

Instead, if the whole function is to be skipped, please prefer:

=C2=A0 =C2=A0 =C2=A0 =C2=A0 if (skip_things_if_true)
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 return;

instead of

=C2=A0 =C2=A0 =C2=A0 =C2=A0 if (!skip_things_if_true) {
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 ...
=C2=A0 =C2=A0 =C2=A0 =C2=A0 }

here and everywhere else.

Specifically, for the kunit_resource design, this would simply become:

=C2=A0 =C2=A0 =C2=A0 =C2=A0 if (slab_add_kunit_errors())
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 return;

Meaning that whenever a KUnit test has a resource "slab_errors", = no
messages are printed -- otherwise it'll always print a message.

> +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0struct va_format vaf;=
> +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0va_list args;
> +
> +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0va_start(args, fmt);<= br> > +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0vaf.fmt =3D fmt;
> +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0vaf.va =3D &args;
> +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0pr_err("FIX %s: = %pV\n", s->name, &vaf);
> +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0va_end(args);
> +=C2=A0 =C2=A0 =C2=A0}
>=C2=A0 }
>=C2=A0
>=C2=A0 static bool freelist_corrupted(struct kmem_cache *s, struct page= *page,
> @@ -739,8 +741,10 @@ static void print_trailer(struct kmem_cache *s, s= truct page *page, u8 *p)
>=C2=A0 void object_err(struct kmem_cache *s, struct page *page,
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0u8 *object, char *reason)
>=C2=A0 {
> -=C2=A0 =C2=A0 =C2=A0slab_bug(s, "%s", reason);
> -=C2=A0 =C2=A0 =C2=A0print_trailer(s, page, object);
> +=C2=A0 =C2=A0 =C2=A0if (!(s->flags & SLAB_SILENT_ERRORS)) { > +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0slab_bug(s, "%s&= quot;, reason);
> +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0print_trailer(s, page= , object);
> +=C2=A0 =C2=A0 =C2=A0}
>=C2=A0 }
>=C2=A0
>=C2=A0 static __printf(3, 4) void slab_err(struct kmem_cache *s, struct= page *page,
> @@ -752,9 +756,11 @@ static __printf(3, 4) void slab_err(struct kmem_c= ache *s, struct page *page,
>=C2=A0 =C2=A0 =C2=A0 =C2=A0va_start(args, fmt);
>=C2=A0 =C2=A0 =C2=A0 =C2=A0vsnprintf(buf, sizeof(buf), fmt, args);
>=C2=A0 =C2=A0 =C2=A0 =C2=A0va_end(args);
> -=C2=A0 =C2=A0 =C2=A0slab_bug(s, "%s", buf);
> -=C2=A0 =C2=A0 =C2=A0print_page_info(page);
> -=C2=A0 =C2=A0 =C2=A0dump_stack();
> +=C2=A0 =C2=A0 =C2=A0if (!(s->flags & SLAB_SILENT_ERRORS)) { > +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0slab_bug(s, "%s&= quot;, buf);
> +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0print_page_info(page)= ;
> +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0dump_stack();
> +=C2=A0 =C2=A0 =C2=A0}
>=C2=A0 }
>=C2=A0
>=C2=A0 static void init_object(struct kmem_cache *s, void *object, u8 v= al)
> @@ -798,11 +804,13 @@ static int check_bytes_and_report(struct kmem_ca= che *s, struct page *page,
>=C2=A0 =C2=A0 =C2=A0 =C2=A0while (end > fault && end[-1] =3D= =3D value)
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0end--;
>=C2=A0
> -=C2=A0 =C2=A0 =C2=A0slab_bug(s, "%s overwritten", what); > -=C2=A0 =C2=A0 =C2=A0pr_err("INFO: 0x%p-0x%p @offset=3D%tu. First= byte 0x%x instead of 0x%x\n",
> +=C2=A0 =C2=A0 =C2=A0if (!(s->flags & SLAB_SILENT_ERRORS)) { > +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0slab_bug(s, "%s = overwritten", what);
> +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0pr_err("INFO: 0x= %p-0x%p @offset=3D%tu. First byte 0x%x instead of 0x%x\n",
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0fault,= end - 1, fault - addr,
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0fault[= 0], value);
> -=C2=A0 =C2=A0 =C2=A0print_trailer(s, page, object);
> +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0print_trailer(s, page= , object);
> +=C2=A0 =C2=A0 =C2=A0}
>=C2=A0
>=C2=A0 =C2=A0 =C2=A0 =C2=A0restore_bytes(s, what, value, fault, end); >=C2=A0 =C2=A0 =C2=A0 =C2=A0return 0;
> @@ -964,6 +972,7 @@ static int check_slab(struct kmem_cache *s, struct= page *page)
>=C2=A0
>=C2=A0 =C2=A0 =C2=A0 =C2=A0if (!PageSlab(page)) {
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0slab_err(s, page= , "Not a valid slab page");
> +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0s->errors +=3D 1;<= br>
So to me it looks like errors is set whenever there's a slab_err() or slab_fix() call. So why not move setting that an error occurred into
those functions?

>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0return 0;
>=C2=A0 =C2=A0 =C2=A0 =C2=A0}
>=C2=A0
> @@ -971,11 +980,13 @@ static int check_slab(struct kmem_cache *s, stru= ct page *page)
>=C2=A0 =C2=A0 =C2=A0 =C2=A0if (page->objects > maxobj) {
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0slab_err(s, page= , "objects %u > max %u",
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0page->objects, maxobj);
> +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0s->errors +=3D 1;<= br> >=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0return 0;
>=C2=A0 =C2=A0 =C2=A0 =C2=A0}
>=C2=A0 =C2=A0 =C2=A0 =C2=A0if (page->inuse > page->objects) {<= br> >=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0slab_err(s, page= , "inuse %u > max %u",
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0page->inuse, page->objects);
> +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0s->errors +=3D 1;<= br> >=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0return 0;
>=C2=A0 =C2=A0 =C2=A0 =C2=A0}
>=C2=A0 =C2=A0 =C2=A0 =C2=A0/* Slab_pad_check fixes things up after itse= lf */
> @@ -1008,8 +1019,10 @@ static int on_freelist(struct kmem_cache *s, st= ruct page *page, void *search)
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0page->freelist =3D NULL;
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0page->inuse =3D page->object= s;
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0slab_fix(s, "Freelist cleared= ");
> +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0= =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0s->errors +=3D 1;
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0return 0;
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0}
> +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0= =C2=A0s->errors +=3D 1;
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0break;
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0}
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0object =3D fp; > @@ -1026,12 +1039,14 @@ static int on_freelist(struct kmem_cache *s, s= truct page *page, void *search)
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 page->objects, max_objects);
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0page->objects= =3D max_objects;
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0slab_fix(s, &quo= t;Number of objects adjusted.");
> +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0s->errors +=3D 1;<= br> >=C2=A0 =C2=A0 =C2=A0 =C2=A0}
>=C2=A0 =C2=A0 =C2=A0 =C2=A0if (page->inuse !=3D page->objects - n= r) {
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0slab_err(s, page= , "Wrong object count. Counter is %d but counted were %d",
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 page->inuse, page->objects - nr);
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0page->inuse = =3D page->objects - nr;
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0slab_fix(s, &quo= t;Object count adjusted.");
> +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0s->errors +=3D 1;<= br> >=C2=A0 =C2=A0 =C2=A0 =C2=A0}
>=C2=A0 =C2=A0 =C2=A0 =C2=A0return search =3D=3D NULL;
>=C2=A0 }
> @@ -4629,8 +4644,10 @@ static void validate_slab(struct kmem_cache *s,= struct page *page)
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0u8 val =3D test_= bit(__obj_to_index(s, addr, p), map) ?
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 SLUB_RED_INACTIVE : SLUB_RED_ACTIVE;
>=C2=A0
> -=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0if (!check_object(s, = page, p, val))
> +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0if (!check_object(s, = page, p, val)) {
> +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0= =C2=A0s->errors +=3D 1;
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0break;
> +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0}
>=C2=A0 =C2=A0 =C2=A0 =C2=A0}
>=C2=A0 =C2=A0 =C2=A0 =C2=A0put_map(map);
>=C2=A0 unlock:
> @@ -4650,9 +4667,11 @@ static int validate_slab_node(struct kmem_cache= *s,
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0validate_slab(s,= page);
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0count++;
>=C2=A0 =C2=A0 =C2=A0 =C2=A0}
> -=C2=A0 =C2=A0 =C2=A0if (count !=3D n->nr_partial)
> +=C2=A0 =C2=A0 =C2=A0if (count !=3D n->nr_partial) {
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0pr_err("SLU= B %s: %ld partial slabs counted but counter=3D%ld\n",
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 s->name, count, n->nr_partial);
> +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0s->errors +=3D 1;<= br> > +=C2=A0 =C2=A0 =C2=A0}
>=C2=A0
>=C2=A0 =C2=A0 =C2=A0 =C2=A0if (!(s->flags & SLAB_STORE_USER)) >=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0goto out;
> @@ -4661,20 +4680,23 @@ static int validate_slab_node(struct kmem_cach= e *s,
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0validate_slab(s,= page);
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0count++;
>=C2=A0 =C2=A0 =C2=A0 =C2=A0}
> -=C2=A0 =C2=A0 =C2=A0if (count !=3D atomic_long_read(&n->nr_sla= bs))
> +=C2=A0 =C2=A0 =C2=A0if (count !=3D atomic_long_read(&n->nr_sla= bs)) {
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0pr_err("SLU= B: %s %ld slabs counted but counter=3D%ld\n",
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 s->name, count, atomic_long_read(&n->nr_slabs));
> +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0s->errors +=3D 1;<= br>
I think these here are a few cases where there's no slab_err() or
slab_fix() call, and open coding setting errors is still required...

> +=C2=A0 =C2=A0 =C2=A0}
>=C2=A0
>=C2=A0 out:
>=C2=A0 =C2=A0 =C2=A0 =C2=A0spin_unlock_irqrestore(&n->list_lock,= flags);
>=C2=A0 =C2=A0 =C2=A0 =C2=A0return count;
>=C2=A0 }
>=C2=A0
> -static long validate_slab_cache(struct kmem_cache *s)
> +long validate_slab_cache(struct kmem_cache *s)
>=C2=A0 {
>=C2=A0 =C2=A0 =C2=A0 =C2=A0int node;
>=C2=A0 =C2=A0 =C2=A0 =C2=A0unsigned long count =3D 0;
>=C2=A0 =C2=A0 =C2=A0 =C2=A0struct kmem_cache_node *n;
> +=C2=A0 =C2=A0 =C2=A0s->errors =3D 0;

This would also go away if you use the kunit_resource design. I also
think it's better if the test fully controls 'slab_errors', and= it isn't
reset by this function.

>=C2=A0 =C2=A0 =C2=A0 =C2=A0flush_all(s);
>=C2=A0 =C2=A0 =C2=A0 =C2=A0for_each_kmem_cache_node(s, node, n)
> @@ -4682,6 +4704,8 @@ static long validate_slab_cache(struct kmem_cach= e *s)
>=C2=A0
>=C2=A0 =C2=A0 =C2=A0 =C2=A0return count;
>=C2=A0 }
> +EXPORT_SYMBOL(validate_slab_cache);
> +
>=C2=A0 /*
>=C2=A0 =C2=A0* Generate lists of code addresses where slabcache objects= are allocated
>=C2=A0 =C2=A0* and freed.
> --
> 2.17.1
--0000000000009ded8505bee6cf6c--