From nobody Tue Jun 30 06:33:01 2026 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 1480AC433F5 for ; Mon, 24 Jan 2022 02:37:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240890AbiAXChw (ORCPT ); Sun, 23 Jan 2022 21:37:52 -0500 Received: from szxga02-in.huawei.com ([45.249.212.188]:17361 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240810AbiAXChp (ORCPT ); Sun, 23 Jan 2022 21:37:45 -0500 Received: from kwepemi500015.china.huawei.com (unknown [172.30.72.56]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4JhvHr3BYCz9sHF; Mon, 24 Jan 2022 10:36:24 +0800 (CST) Received: from kwepemm600017.china.huawei.com (7.193.23.234) by kwepemi500015.china.huawei.com (7.221.188.92) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.21; Mon, 24 Jan 2022 10:37:42 +0800 Received: from localhost.localdomain (10.175.112.125) by kwepemm600017.china.huawei.com (7.193.23.234) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.21; Mon, 24 Jan 2022 10:37:41 +0800 From: Peng Liu To: , , , , , , CC: , , , , , Subject: [PATCH RFC 1/3] kfence: Add a module parameter to adjust kfence objects Date: Mon, 24 Jan 2022 02:52:03 +0000 Message-ID: <20220124025205.329752-2-liupeng256@huawei.com> X-Mailer: git-send-email 2.18.0.huawei.25 In-Reply-To: <20220124025205.329752-1-liupeng256@huawei.com> References: <20220124025205.329752-1-liupeng256@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.175.112.125] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To kwepemm600017.china.huawei.com (7.193.23.234) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" KFENCE is designed to be enabled in production kernels, but it can be also useful in some debug situations. For machines with limited memory and CPU resources, KASAN is really hard to run. Fortunately, KFENCE can be a suitable candidate. For KFENCE running on a single machine, the possibility of discovering existed bugs will increase as the increasing of KFENCE objects, but this will cost more memory. In order to balance the possibility of discovering existed bugs and memory cost, KFENCE objects need to be adjusted according to memory resources for a compiled kernel Image. Add a module parameter to adjust KFENCE objects will make kfence to use in different machines with the same kernel Image. In short, the following reasons motivate us to add this parameter. 1) In some debug situations, this will make kfence flexible. 2) For some production machines with different memory and CPU size, this will reduce the kernel-Image-version burden. The main change is just using kfence_num_objects to replace config CONFIG_KFENCE_NUM_OBJECTS for dynamic configuration convenient. To make compatible, kfence_metadata and alloc_covered are alloced by memblock_alloc. Considering "cat /sys/kernel/debug/kfence/objects" will read kfence_metadata, the initialization of this fs should check whether kfence_metadata is successfully allocated. This patch (of 3): The most important motivation of this patch series is to make KFENCE easy-to-use in business situations. Signed-off-by: Peng Liu --- Documentation/dev-tools/kfence.rst | 14 ++-- include/linux/kfence.h | 3 +- mm/kfence/core.c | 108 ++++++++++++++++++++++++----- mm/kfence/kfence.h | 2 +- mm/kfence/kfence_test.c | 2 +- 5 files changed, 103 insertions(+), 26 deletions(-) diff --git a/Documentation/dev-tools/kfence.rst b/Documentation/dev-tools/k= fence.rst index ac6b89d1a8c3..e079dfb81dfe 100644 --- a/Documentation/dev-tools/kfence.rst +++ b/Documentation/dev-tools/kfence.rst @@ -41,12 +41,14 @@ guarded by KFENCE. The default is configurable via the = Kconfig option ``CONFIG_KFENCE_SAMPLE_INTERVAL``. Setting ``kfence.sample_interval=3D0`` disables KFENCE. =20 -The KFENCE memory pool is of fixed size, and if the pool is exhausted, no -further KFENCE allocations occur. With ``CONFIG_KFENCE_NUM_OBJECTS`` (defa= ult -255), the number of available guarded objects can be controlled. Each obje= ct -requires 2 pages, one for the object itself and the other one used as a gu= ard -page; object pages are interleaved with guard pages, and every object page= is -therefore surrounded by two guard pages. +The KFENCE memory pool size is also an important parameter, which can be +can be set via the kernel boot parameter ``kfence.num_objects``, and if the +pool is exhausted, no further KFENCE allocations occur. The KFENCE memory +pool size Each object requires 2 pages, one for the object itself and the +other one used as a guard page; object pages are interleaved with guard pa= ges, +and every object page is therefore surrounded by two guard pages. The defa= ult +is configurable via the Kconfig option ``CONFIG_KFENCE_SAMPLE_INTERVAL`` +(default 255). =20 The total memory dedicated to the KFENCE memory pool can be computed as:: =20 diff --git a/include/linux/kfence.h b/include/linux/kfence.h index 4b5e3679a72c..aec4f6b247b5 100644 --- a/include/linux/kfence.h +++ b/include/linux/kfence.h @@ -17,12 +17,13 @@ #include #include =20 +extern unsigned long kfence_num_objects; /* * We allocate an even number of pages, as it simplifies calculations to m= ap * address to metadata indices; effectively, the very first page serves as= an * extended guard page, but otherwise has no special purpose. */ -#define KFENCE_POOL_SIZE ((CONFIG_KFENCE_NUM_OBJECTS + 1) * 2 * PAGE_SIZE) +#define KFENCE_POOL_SIZE ((kfence_num_objects + 1) * 2 * PAGE_SIZE) extern char *__kfence_pool; =20 DECLARE_STATIC_KEY_FALSE(kfence_allocation_key); diff --git a/mm/kfence/core.c b/mm/kfence/core.c index 5ad40e3add45..4655bcc0306e 100644 --- a/mm/kfence/core.c +++ b/mm/kfence/core.c @@ -34,6 +34,9 @@ =20 #include "kfence.h" =20 +#define MIN_KFENCE_OBJECTS 1 +#define MAX_KFENCE_OBJECTS 65535 + /* Disables KFENCE on the first warning assuming an irrecoverable error. */ #define KFENCE_WARN_ON(cond) = \ ({ \ @@ -93,12 +96,53 @@ module_param_named(skip_covered_thresh, kfence_skip_cov= ered_thresh, ulong, 0644) char *__kfence_pool __ro_after_init; EXPORT_SYMBOL(__kfence_pool); /* Export for test modules. */ =20 +/* + * The number of kfence objects will affect performance and bug detection + * accuracy. The initial value of this global parameter is determined by + * compiling settings. + */ +unsigned long kfence_num_objects =3D CONFIG_KFENCE_NUM_OBJECTS; +EXPORT_SYMBOL(kfence_num_objects); /* Export for test modules. */ + +static int param_set_num_objects(const char *val, const struct kernel_para= m *kp) +{ + unsigned long num; + + if (system_state !=3D SYSTEM_BOOTING) + return -EINVAL; /* Cannot adjust KFENCE objects number on-the-fly. */ + + if (kstrtoul(val, 0, &num) < 0) + return -EINVAL; + + if (num < MIN_KFENCE_OBJECTS || num > MAX_KFENCE_OBJECTS) { + pr_warn("kfence_num_objects =3D %lu is not in valid range [%d,%d]\n", + num, MIN_KFENCE_OBJECTS, MAX_KFENCE_OBJECTS); + return -EINVAL; + } + + *((unsigned long *)kp->arg) =3D num; + return 0; +} + +static int param_get_num_objects(char *buffer, const struct kernel_param *= kp) +{ + if (!READ_ONCE(kfence_enabled)) + return sprintf(buffer, "0\n"); + + return param_get_ulong(buffer, kp); +} + +static const struct kernel_param_ops num_objects_param_ops =3D { + .set =3D param_set_num_objects, + .get =3D param_get_num_objects, +}; +module_param_cb(num_objects, &num_objects_param_ops, &kfence_num_objects, = 0600); + /* * Per-object metadata, with one-to-one mapping of object metadata to * backing pages (in __kfence_pool). */ -static_assert(CONFIG_KFENCE_NUM_OBJECTS > 0); -struct kfence_metadata kfence_metadata[CONFIG_KFENCE_NUM_OBJECTS]; +struct kfence_metadata *kfence_metadata; =20 /* Freelist with available objects. */ static struct list_head kfence_freelist =3D LIST_HEAD_INIT(kfence_freelist= ); @@ -124,11 +168,11 @@ atomic_t kfence_allocation_gate =3D ATOMIC_INIT(1); * P(alloc_traces) =3D (1 - e^(-HNUM * (alloc_traces / SIZE)) ^ HNUM */ #define ALLOC_COVERED_HNUM 2 -#define ALLOC_COVERED_ORDER (const_ilog2(CONFIG_KFENCE_NUM_OBJECTS) + 2) +#define ALLOC_COVERED_ORDER (const_ilog2(kfence_num_objects) + 2) #define ALLOC_COVERED_SIZE (1 << ALLOC_COVERED_ORDER) #define ALLOC_COVERED_HNEXT(h) hash_32(h, ALLOC_COVERED_ORDER) #define ALLOC_COVERED_MASK (ALLOC_COVERED_SIZE - 1) -static atomic_t alloc_covered[ALLOC_COVERED_SIZE]; +static atomic_t *alloc_covered; =20 /* Stack depth used to determine uniqueness of an allocation. */ #define UNIQUE_ALLOC_STACK_DEPTH ((size_t)8) @@ -168,7 +212,7 @@ static_assert(ARRAY_SIZE(counter_names) =3D=3D KFENCE_C= OUNTER_COUNT); =20 static inline bool should_skip_covered(void) { - unsigned long thresh =3D (CONFIG_KFENCE_NUM_OBJECTS * kfence_skip_covered= _thresh) / 100; + unsigned long thresh =3D (kfence_num_objects * kfence_skip_covered_thresh= ) / 100; =20 return atomic_long_read(&counters[KFENCE_COUNTER_ALLOCATED]) > thresh; } @@ -236,7 +280,7 @@ static inline struct kfence_metadata *addr_to_metadata(= unsigned long addr) * error. */ index =3D (addr - (unsigned long)__kfence_pool) / (PAGE_SIZE * 2) - 1; - if (index < 0 || index >=3D CONFIG_KFENCE_NUM_OBJECTS) + if (index < 0 || index >=3D kfence_num_objects) return NULL; =20 return &kfence_metadata[index]; @@ -251,7 +295,7 @@ static inline unsigned long metadata_to_pageaddr(const = struct kfence_metadata *m =20 /* Only call with a pointer into kfence_metadata. */ if (KFENCE_WARN_ON(meta < kfence_metadata || - meta >=3D kfence_metadata + CONFIG_KFENCE_NUM_OBJECTS)) + meta >=3D kfence_metadata + kfence_num_objects)) return 0; =20 /* @@ -577,7 +621,7 @@ static bool __init kfence_init_pool(void) addr +=3D PAGE_SIZE; } =20 - for (i =3D 0; i < CONFIG_KFENCE_NUM_OBJECTS; i++) { + for (i =3D 0; i < kfence_num_objects; i++) { struct kfence_metadata *meta =3D &kfence_metadata[i]; =20 /* Initialize metadata. */ @@ -638,7 +682,7 @@ DEFINE_SHOW_ATTRIBUTE(stats); */ static void *start_object(struct seq_file *seq, loff_t *pos) { - if (*pos < CONFIG_KFENCE_NUM_OBJECTS) + if (*pos < kfence_num_objects) return (void *)((long)*pos + 1); return NULL; } @@ -650,7 +694,7 @@ static void stop_object(struct seq_file *seq, void *v) static void *next_object(struct seq_file *seq, void *v, loff_t *pos) { ++*pos; - if (*pos < CONFIG_KFENCE_NUM_OBJECTS) + if (*pos < kfence_num_objects) return (void *)((long)*pos + 1); return NULL; } @@ -692,7 +736,10 @@ static int __init kfence_debugfs_init(void) struct dentry *kfence_dir =3D debugfs_create_dir("kfence", NULL); =20 debugfs_create_file("stats", 0444, kfence_dir, NULL, &stats_fops); - debugfs_create_file("objects", 0400, kfence_dir, NULL, &objects_fops); + + /* Variable kfence_metadata may fail to allocate. */ + if (kfence_metadata) + debugfs_create_file("objects", 0400, kfence_dir, NULL, &objects_fops); return 0; } =20 @@ -756,13 +803,40 @@ static DECLARE_DELAYED_WORK(kfence_timer, toggle_allo= cation_gate); =20 void __init kfence_alloc_pool(void) { + phys_addr_t metadata_size; + phys_addr_t covered_size; + if (!kfence_sample_interval) return; =20 - __kfence_pool =3D memblock_alloc(KFENCE_POOL_SIZE, PAGE_SIZE); + metadata_size =3D sizeof(struct kfence_metadata) * kfence_num_objects; + kfence_metadata =3D memblock_alloc(metadata_size, PAGE_SIZE); + if (!kfence_metadata) { + pr_err("failed to allocate metadata\n"); + return; + } =20 - if (!__kfence_pool) + covered_size =3D sizeof(atomic_t) * kfence_num_objects; + alloc_covered =3D memblock_alloc(covered_size, PAGE_SIZE); + if (!alloc_covered) { + pr_err("failed to allocate covered\n"); + goto fail_covered; + } + + __kfence_pool =3D memblock_alloc(KFENCE_POOL_SIZE, PAGE_SIZE); + if (!__kfence_pool) { pr_err("failed to allocate pool\n"); + goto fail_pool; + } + + return; + +fail_pool: + memblock_free(alloc_covered, covered_size); + alloc_covered =3D NULL; +fail_covered: + memblock_free(kfence_metadata, metadata_size); + kfence_metadata =3D NULL; } =20 void __init kfence_init(void) @@ -781,8 +855,8 @@ void __init kfence_init(void) static_branch_enable(&kfence_allocation_key); WRITE_ONCE(kfence_enabled, true); queue_delayed_work(system_unbound_wq, &kfence_timer, 0); - pr_info("initialized - using %lu bytes for %d objects at 0x%p-0x%p\n", KF= ENCE_POOL_SIZE, - CONFIG_KFENCE_NUM_OBJECTS, (void *)__kfence_pool, + pr_info("initialized - using %lu bytes for %lu objects at 0x%p-0x%p\n", K= FENCE_POOL_SIZE, + kfence_num_objects, (void *)__kfence_pool, (void *)(__kfence_pool + KFENCE_POOL_SIZE)); } =20 @@ -792,7 +866,7 @@ void kfence_shutdown_cache(struct kmem_cache *s) struct kfence_metadata *meta; int i; =20 - for (i =3D 0; i < CONFIG_KFENCE_NUM_OBJECTS; i++) { + for (i =3D 0; i < kfence_num_objects; i++) { bool in_use; =20 meta =3D &kfence_metadata[i]; @@ -831,7 +905,7 @@ void kfence_shutdown_cache(struct kmem_cache *s) } } =20 - for (i =3D 0; i < CONFIG_KFENCE_NUM_OBJECTS; i++) { + for (i =3D 0; i < kfence_num_objects; i++) { meta =3D &kfence_metadata[i]; =20 /* See above. */ diff --git a/mm/kfence/kfence.h b/mm/kfence/kfence.h index 2a2d5de9d379..c6d37fad977a 100644 --- a/mm/kfence/kfence.h +++ b/mm/kfence/kfence.h @@ -91,7 +91,7 @@ struct kfence_metadata { u32 alloc_stack_hash; }; =20 -extern struct kfence_metadata kfence_metadata[CONFIG_KFENCE_NUM_OBJECTS]; +extern struct kfence_metadata *kfence_metadata; =20 /* KFENCE error types for report generation. */ enum kfence_error_type { diff --git a/mm/kfence/kfence_test.c b/mm/kfence/kfence_test.c index a22b1af85577..084e3a55aebb 100644 --- a/mm/kfence/kfence_test.c +++ b/mm/kfence/kfence_test.c @@ -623,7 +623,7 @@ static void test_gfpzero(struct kunit *test) break; test_free(buf2); =20 - if (i =3D=3D CONFIG_KFENCE_NUM_OBJECTS) { + if (i =3D=3D kfence_num_objects) { kunit_warn(test, "giving up ... cannot get same object back\n"); return; } --=20 2.18.0.huawei.25 From nobody Tue Jun 30 06:33:01 2026 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 2D460C433EF for ; Mon, 24 Jan 2022 02:37:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240909AbiAXChx (ORCPT ); Sun, 23 Jan 2022 21:37:53 -0500 Received: from szxga03-in.huawei.com ([45.249.212.189]:31179 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240814AbiAXChr (ORCPT ); Sun, 23 Jan 2022 21:37:47 -0500 Received: from kwepemi500013.china.huawei.com (unknown [172.30.72.54]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4JhvG070gtz8wTb; Mon, 24 Jan 2022 10:34:48 +0800 (CST) Received: from kwepemm600017.china.huawei.com (7.193.23.234) by kwepemi500013.china.huawei.com (7.221.188.120) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.21; Mon, 24 Jan 2022 10:37:43 +0800 Received: from localhost.localdomain (10.175.112.125) by kwepemm600017.china.huawei.com (7.193.23.234) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.21; Mon, 24 Jan 2022 10:37:42 +0800 From: Peng Liu To: , , , , , , CC: , , , , , Subject: [PATCH RFC 2/3] kfence: Optimize branches prediction when sample interval is zero Date: Mon, 24 Jan 2022 02:52:04 +0000 Message-ID: <20220124025205.329752-3-liupeng256@huawei.com> X-Mailer: git-send-email 2.18.0.huawei.25 In-Reply-To: <20220124025205.329752-1-liupeng256@huawei.com> References: <20220124025205.329752-1-liupeng256@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.175.112.125] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To kwepemm600017.china.huawei.com (7.193.23.234) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" In order to release a uniform kernel with KFENCE, it is good to compile it with CONFIG_KFENCE_SAMPLE_INTERVAL =3D 0. For a group of produtions who don't want to use KFENCE, they can use kernel just as original vesion without KFENCE. For KFENCE users, they can open it by setting the kernel boot parameter kfence.sample_interval. Hence, set KFENCE sample interval default to zero is convenient. The current KFENCE is supportted to adjust sample interval via the kernel boot parameter. However, branches prediction in kfence_alloc is not good for situation with CONFIG_KFENCE_SAMPLE_INTERVAL =3D 0 and boot parameter kfence.sample_interval !=3D 0, which is because the current kfence_alloc is likely to return NULL when CONFIG_KFENCE_SAMPLE_INTERVAL =3D 0. To optimize branches prediction in this situation, kfence_enabled will check firstly. Signed-off-by: Peng Liu --- include/linux/kfence.h | 5 ++++- mm/kfence/core.c | 2 +- 2 files changed, 5 insertions(+), 2 deletions(-) diff --git a/include/linux/kfence.h b/include/linux/kfence.h index aec4f6b247b5..bf91b76b87ee 100644 --- a/include/linux/kfence.h +++ b/include/linux/kfence.h @@ -17,6 +17,7 @@ #include #include =20 +extern bool kfence_enabled; extern unsigned long kfence_num_objects; /* * We allocate an even number of pages, as it simplifies calculations to m= ap @@ -115,7 +116,9 @@ void *__kfence_alloc(struct kmem_cache *s, size_t size,= gfp_t flags); */ static __always_inline void *kfence_alloc(struct kmem_cache *s, size_t siz= e, gfp_t flags) { -#if defined(CONFIG_KFENCE_STATIC_KEYS) || CONFIG_KFENCE_SAMPLE_INTERVAL = =3D=3D 0 + if (!kfence_enabled) + return NULL; +#if defined(CONFIG_KFENCE_STATIC_KEYS) if (!static_branch_unlikely(&kfence_allocation_key)) return NULL; #else diff --git a/mm/kfence/core.c b/mm/kfence/core.c index 4655bcc0306e..2301923182b8 100644 --- a/mm/kfence/core.c +++ b/mm/kfence/core.c @@ -48,7 +48,7 @@ =20 /* =3D=3D=3D Data =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D */ =20 -static bool kfence_enabled __read_mostly; +bool kfence_enabled __read_mostly; =20 static unsigned long kfence_sample_interval __read_mostly =3D CONFIG_KFENC= E_SAMPLE_INTERVAL; =20 --=20 2.18.0.huawei.25 From nobody Tue Jun 30 06:33:01 2026 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 110A2C433F5 for ; Mon, 24 Jan 2022 02:37:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240814AbiAXChz (ORCPT ); Sun, 23 Jan 2022 21:37:55 -0500 Received: from szxga02-in.huawei.com ([45.249.212.188]:30294 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240797AbiAXChr (ORCPT ); Sun, 23 Jan 2022 21:37:47 -0500 Received: from kwepemi100026.china.huawei.com (unknown [172.30.72.55]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4JhvJR4KKjzbk5R; Mon, 24 Jan 2022 10:36:55 +0800 (CST) Received: from kwepemm600017.china.huawei.com (7.193.23.234) by kwepemi100026.china.huawei.com (7.221.188.60) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.21; Mon, 24 Jan 2022 10:37:44 +0800 Received: from localhost.localdomain (10.175.112.125) by kwepemm600017.china.huawei.com (7.193.23.234) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.21; Mon, 24 Jan 2022 10:37:43 +0800 From: Peng Liu To: , , , , , , CC: , , , , , Subject: [PATCH RFC 3/3] kfence: Make test case compatible with run time set sample interval Date: Mon, 24 Jan 2022 02:52:05 +0000 Message-ID: <20220124025205.329752-4-liupeng256@huawei.com> X-Mailer: git-send-email 2.18.0.huawei.25 In-Reply-To: <20220124025205.329752-1-liupeng256@huawei.com> References: <20220124025205.329752-1-liupeng256@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.175.112.125] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To kwepemm600017.china.huawei.com (7.193.23.234) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The parameter kfence_sample_interval can be set via boot parameter and late shell command. However, KFENCE test case just use compile time CONFIG_KFENCE_SAMPLE_INTERVAL, this will make KFENCE test case not run as user desired. This patch will make KFENCE test case compatible with run-time-set sample interval. Signed-off-by: Peng Liu --- include/linux/kfence.h | 2 ++ mm/kfence/core.c | 3 ++- mm/kfence/kfence_test.c | 8 ++++---- 3 files changed, 8 insertions(+), 5 deletions(-) diff --git a/include/linux/kfence.h b/include/linux/kfence.h index bf91b76b87ee..0fc913a7f017 100644 --- a/include/linux/kfence.h +++ b/include/linux/kfence.h @@ -19,6 +19,8 @@ =20 extern bool kfence_enabled; extern unsigned long kfence_num_objects; +extern unsigned long kfence_sample_interval; + /* * We allocate an even number of pages, as it simplifies calculations to m= ap * address to metadata indices; effectively, the very first page serves as= an diff --git a/mm/kfence/core.c b/mm/kfence/core.c index 2301923182b8..e2fcae34cc84 100644 --- a/mm/kfence/core.c +++ b/mm/kfence/core.c @@ -50,7 +50,8 @@ =20 bool kfence_enabled __read_mostly; =20 -static unsigned long kfence_sample_interval __read_mostly =3D CONFIG_KFENC= E_SAMPLE_INTERVAL; +unsigned long kfence_sample_interval __read_mostly =3D CONFIG_KFENCE_SAMPL= E_INTERVAL; +EXPORT_SYMBOL(kfence_sample_interval); /* Export for test modules. */ =20 #ifdef MODULE_PARAM_PREFIX #undef MODULE_PARAM_PREFIX diff --git a/mm/kfence/kfence_test.c b/mm/kfence/kfence_test.c index 084e3a55aebb..97ff3a133f11 100644 --- a/mm/kfence/kfence_test.c +++ b/mm/kfence/kfence_test.c @@ -268,13 +268,13 @@ static void *test_alloc(struct kunit *test, size_t si= ze, gfp_t gfp, enum allocat * 100x the sample interval should be more than enough to ensure we get * a KFENCE allocation eventually. */ - timeout =3D jiffies + msecs_to_jiffies(100 * CONFIG_KFENCE_SAMPLE_INTERVA= L); + timeout =3D jiffies + msecs_to_jiffies(100 * kfence_sample_interval); /* * Especially for non-preemption kernels, ensure the allocation-gate * timer can catch up: after @resched_after, every failed allocation * attempt yields, to ensure the allocation-gate timer is scheduled. */ - resched_after =3D jiffies + msecs_to_jiffies(CONFIG_KFENCE_SAMPLE_INTERVA= L); + resched_after =3D jiffies + msecs_to_jiffies(kfence_sample_interval); do { if (test_cache) alloc =3D kmem_cache_alloc(test_cache, gfp); @@ -608,7 +608,7 @@ static void test_gfpzero(struct kunit *test) int i; =20 /* Skip if we think it'd take too long. */ - KFENCE_TEST_REQUIRES(test, CONFIG_KFENCE_SAMPLE_INTERVAL <=3D 100); + KFENCE_TEST_REQUIRES(test, kfence_sample_interval <=3D 100); =20 setup_test_cache(test, size, 0, NULL); buf1 =3D test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY); @@ -739,7 +739,7 @@ static void test_memcache_alloc_bulk(struct kunit *test) * 100x the sample interval should be more than enough to ensure we get * a KFENCE allocation eventually. */ - timeout =3D jiffies + msecs_to_jiffies(100 * CONFIG_KFENCE_SAMPLE_INTERVA= L); + timeout =3D jiffies + msecs_to_jiffies(100 * kfence_sample_interval); do { void *objects[100]; int i, num =3D kmem_cache_alloc_bulk(test_cache, GFP_ATOMIC, ARRAY_SIZE(= objects), --=20 2.18.0.huawei.25