From patchwork Mon Aug 12 16:06:42 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Catalin Marinas X-Patchwork-Id: 11090095 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 9D0291399 for ; Mon, 12 Aug 2019 16:07:27 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8C95328334 for ; Mon, 12 Aug 2019 16:07:27 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8079128514; Mon, 12 Aug 2019 16:07:27 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 37A6128334 for ; Mon, 12 Aug 2019 16:07:26 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 7BCF56B000A; Mon, 12 Aug 2019 12:07:21 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 6F7246B000C; Mon, 12 Aug 2019 12:07:21 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 60E176B000E; Mon, 12 Aug 2019 12:07:21 -0400 (EDT) X-Original-To: linux-mm@kvack.org 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 245616B000A for ; Mon, 12 Aug 2019 12:07:21 -0400 (EDT) Received: from smtpin09.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with SMTP id 9DDA9181AC9B4 for ; Mon, 12 Aug 2019 16:07:20 +0000 (UTC) X-FDA: 75814255440.09.stone24_5bd2d8acf90b X-HE-Tag: stone24_5bd2d8acf90b X-Filterd-Recvd-Size: 18423 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf12.hostedemail.com (Postfix) with ESMTP for ; Mon, 12 Aug 2019 16:07:19 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B4FE71993; Mon, 12 Aug 2019 09:06:50 -0700 (PDT) Received: from arrakis.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 97DD43F718; Mon, 12 Aug 2019 09:06:49 -0700 (PDT) From: Catalin Marinas To: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, Andrew Morton , Michal Hocko , Matthew Wilcox , Qian Cai Subject: [PATCH v3 3/3] mm: kmemleak: Use the memory pool for early allocations Date: Mon, 12 Aug 2019 17:06:42 +0100 Message-Id: <20190812160642.52134-4-catalin.marinas@arm.com> X-Mailer: git-send-email 2.23.0.rc0 In-Reply-To: <20190812160642.52134-1-catalin.marinas@arm.com> References: <20190812160642.52134-1-catalin.marinas@arm.com> MIME-Version: 1.0 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: X-Virus-Scanned: ClamAV using ClamSMTP Currently kmemleak uses a static early_log buffer to trace all memory allocation/freeing before the slab allocator is initialised. Such early log is replayed during kmemleak_init() to properly initialise the kmemleak metadata for objects allocated up that point. With a memory pool that does not rely on the slab allocator, it is possible to skip this early log entirely. In order to remove the early logging, consider kmemleak_enabled == 1 by default while the kmem_cache availability is checked directly on the object_cache and scan_area_cache variables. The RCU callback is only invoked after object_cache has been initialised as we wouldn't have any concurrent list traversal before this. In order to reduce the number of callbacks before kmemleak is fully initialised, move the kmemleak_init() call to mm_init(). Signed-off-by: Catalin Marinas --- init/main.c | 2 +- lib/Kconfig.debug | 11 +- mm/kmemleak.c | 267 +++++----------------------------------------- 3 files changed, 35 insertions(+), 245 deletions(-) diff --git a/init/main.c b/init/main.c index 96f8d5af52d6..ca05e3cd7ef7 100644 --- a/init/main.c +++ b/init/main.c @@ -556,6 +556,7 @@ static void __init mm_init(void) report_meminit(); mem_init(); kmem_cache_init(); + kmemleak_init(); pgtable_init(); debug_objects_mem_init(); vmalloc_init(); @@ -740,7 +741,6 @@ asmlinkage __visible void __init start_kernel(void) initrd_start = 0; } #endif - kmemleak_init(); setup_per_cpu_pageset(); numa_policy_init(); acpi_early_init(); diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 4d39540011e2..39df06ffd9f4 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -592,17 +592,18 @@ config DEBUG_KMEMLEAK In order to access the kmemleak file, debugfs needs to be mounted (usually at /sys/kernel/debug). -config DEBUG_KMEMLEAK_EARLY_LOG_SIZE - int "Maximum kmemleak early log entries" +config DEBUG_KMEMLEAK_MEM_POOL_SIZE + int "Kmemleak memory pool size" depends on DEBUG_KMEMLEAK range 200 40000 default 16000 help Kmemleak must track all the memory allocations to avoid reporting false positives. Since memory may be allocated or - freed before kmemleak is initialised, an early log buffer is - used to store these actions. If kmemleak reports "early log - buffer exceeded", please increase this value. + freed before kmemleak is fully initialised, use a static pool + of metadata objects to track such callbacks. After kmemleak is + fully initialised, this memory pool acts as an emergency one + if slab allocations fail. config DEBUG_KMEMLEAK_TEST tristate "Simple test for the kernel memory leak detector" diff --git a/mm/kmemleak.c b/mm/kmemleak.c index 2fb86524d70b..bcb05b9b4eb4 100644 --- a/mm/kmemleak.c +++ b/mm/kmemleak.c @@ -180,15 +180,13 @@ struct kmemleak_object { #define HEX_ASCII 1 /* max number of lines to be printed */ #define HEX_MAX_LINES 2 -/* memory pool size */ -#define MEM_POOL_SIZE 16000 /* the list of all allocated objects */ static LIST_HEAD(object_list); /* the list of gray-colored objects (see color_gray comment below) */ static LIST_HEAD(gray_list); /* memory pool allocation */ -static struct kmemleak_object mem_pool[MEM_POOL_SIZE]; +static struct kmemleak_object mem_pool[CONFIG_DEBUG_KMEMLEAK_MEM_POOL_SIZE]; static int mem_pool_free_count = ARRAY_SIZE(mem_pool); static LIST_HEAD(mem_pool_free_list); /* search tree for object boundaries */ @@ -201,13 +199,11 @@ static struct kmem_cache *object_cache; static struct kmem_cache *scan_area_cache; /* set if tracing memory operations is enabled */ -static int kmemleak_enabled; +static int kmemleak_enabled = 1; /* same as above but only for the kmemleak_free() callback */ -static int kmemleak_free_enabled; +static int kmemleak_free_enabled = 1; /* set in the late_initcall if there were no errors */ static int kmemleak_initialized; -/* enables or disables early logging of the memory operations */ -static int kmemleak_early_log = 1; /* set if a kmemleak warning was issued */ static int kmemleak_warning; /* set if a fatal kmemleak error has occurred */ @@ -235,49 +231,6 @@ static bool kmemleak_found_leaks; static bool kmemleak_verbose; module_param_named(verbose, kmemleak_verbose, bool, 0600); -/* - * Early object allocation/freeing logging. Kmemleak is initialized after the - * kernel allocator. However, both the kernel allocator and kmemleak may - * allocate memory blocks which need to be tracked. Kmemleak defines an - * arbitrary buffer to hold the allocation/freeing information before it is - * fully initialized. - */ - -/* kmemleak operation type for early logging */ -enum { - KMEMLEAK_ALLOC, - KMEMLEAK_ALLOC_PERCPU, - KMEMLEAK_FREE, - KMEMLEAK_FREE_PART, - KMEMLEAK_FREE_PERCPU, - KMEMLEAK_NOT_LEAK, - KMEMLEAK_IGNORE, - KMEMLEAK_SCAN_AREA, - KMEMLEAK_NO_SCAN, - KMEMLEAK_SET_EXCESS_REF -}; - -/* - * Structure holding the information passed to kmemleak callbacks during the - * early logging. - */ -struct early_log { - int op_type; /* kmemleak operation type */ - int min_count; /* minimum reference count */ - const void *ptr; /* allocated/freed memory block */ - union { - size_t size; /* memory block size */ - unsigned long excess_ref; /* surplus reference passing */ - }; - unsigned long trace[MAX_TRACE]; /* stack trace */ - unsigned int trace_len; /* stack trace length */ -}; - -/* early logging buffer and current position */ -static struct early_log - early_log[CONFIG_DEBUG_KMEMLEAK_EARLY_LOG_SIZE] __initdata; -static int crt_early_log __initdata; - static void kmemleak_disable(void); /* @@ -466,9 +419,13 @@ static struct kmemleak_object *mem_pool_alloc(gfp_t gfp) struct kmemleak_object *object; /* try the slab allocator first */ - object = kmem_cache_alloc(object_cache, gfp_kmemleak_mask(gfp)); - if (object) - return object; + if (object_cache) { + object = kmem_cache_alloc(object_cache, gfp_kmemleak_mask(gfp)); + if (object) + return object; + else + WARN_ON_ONCE(1); + } /* slab allocation failed, try the memory pool */ write_lock_irqsave(&kmemleak_lock, flags); @@ -478,6 +435,8 @@ static struct kmemleak_object *mem_pool_alloc(gfp_t gfp) list_del(&object->object_list); else if (mem_pool_free_count) object = &mem_pool[--mem_pool_free_count]; + else + pr_warn_once("Memory pool empty, consider increasing CONFIG_DEBUG_KMEMLEAK_MEM_POOL_SIZE\n"); write_unlock_irqrestore(&kmemleak_lock, flags); return object; @@ -537,7 +496,15 @@ static void put_object(struct kmemleak_object *object) /* should only get here after delete_object was called */ WARN_ON(object->flags & OBJECT_ALLOCATED); - call_rcu(&object->rcu, free_object_rcu); + /* + * It may be too early for the RCU callbacks, however, there is no + * concurrent object_list traversal when !object_cache and all objects + * came from the memory pool. Free the object directly. + */ + if (object_cache) + call_rcu(&object->rcu, free_object_rcu); + else + free_object_rcu(&object->rcu); } /* @@ -741,9 +708,7 @@ static void delete_object_part(unsigned long ptr, size_t size) /* * Create one or two objects that may result from the memory block * split. Note that partial freeing is only done by free_bootmem() and - * this happens before kmemleak_init() is called. The path below is - * only executed during early log recording in kmemleak_init(), so - * GFP_KERNEL is enough. + * this happens before kmemleak_init() is called. */ start = object->pointer; end = object->pointer + object->size; @@ -815,7 +780,7 @@ static void add_scan_area(unsigned long ptr, size_t size, gfp_t gfp) { unsigned long flags; struct kmemleak_object *object; - struct kmemleak_scan_area *area; + struct kmemleak_scan_area *area = NULL; object = find_and_get_object(ptr, 1); if (!object) { @@ -824,7 +789,8 @@ static void add_scan_area(unsigned long ptr, size_t size, gfp_t gfp) return; } - area = kmem_cache_alloc(scan_area_cache, gfp_kmemleak_mask(gfp)); + if (scan_area_cache) + area = kmem_cache_alloc(scan_area_cache, gfp_kmemleak_mask(gfp)); spin_lock_irqsave(&object->lock, flags); if (!area) { @@ -898,86 +864,6 @@ static void object_no_scan(unsigned long ptr) put_object(object); } -/* - * Log an early kmemleak_* call to the early_log buffer. These calls will be - * processed later once kmemleak is fully initialized. - */ -static void __init log_early(int op_type, const void *ptr, size_t size, - int min_count) -{ - unsigned long flags; - struct early_log *log; - - if (kmemleak_error) { - /* kmemleak stopped recording, just count the requests */ - crt_early_log++; - return; - } - - if (crt_early_log >= ARRAY_SIZE(early_log)) { - crt_early_log++; - kmemleak_disable(); - return; - } - - /* - * There is no need for locking since the kernel is still in UP mode - * at this stage. Disabling the IRQs is enough. - */ - local_irq_save(flags); - log = &early_log[crt_early_log]; - log->op_type = op_type; - log->ptr = ptr; - log->size = size; - log->min_count = min_count; - log->trace_len = __save_stack_trace(log->trace); - crt_early_log++; - local_irq_restore(flags); -} - -/* - * Log an early allocated block and populate the stack trace. - */ -static void early_alloc(struct early_log *log) -{ - struct kmemleak_object *object; - unsigned long flags; - int i; - - if (!kmemleak_enabled || !log->ptr || IS_ERR(log->ptr)) - return; - - /* - * RCU locking needed to ensure object is not freed via put_object(). - */ - rcu_read_lock(); - object = create_object((unsigned long)log->ptr, log->size, - log->min_count, GFP_ATOMIC); - if (!object) - goto out; - spin_lock_irqsave(&object->lock, flags); - for (i = 0; i < log->trace_len; i++) - object->trace[i] = log->trace[i]; - object->trace_len = log->trace_len; - spin_unlock_irqrestore(&object->lock, flags); -out: - rcu_read_unlock(); -} - -/* - * Log an early allocated block and populate the stack trace. - */ -static void early_alloc_percpu(struct early_log *log) -{ - unsigned int cpu; - const void __percpu *ptr = log->ptr; - - for_each_possible_cpu(cpu) { - log->ptr = per_cpu_ptr(ptr, cpu); - early_alloc(log); - } -} - /** * kmemleak_alloc - register a newly allocated object * @ptr: pointer to beginning of the object @@ -999,8 +885,6 @@ void __ref kmemleak_alloc(const void *ptr, size_t size, int min_count, if (kmemleak_enabled && ptr && !IS_ERR(ptr)) create_object((unsigned long)ptr, size, min_count, gfp); - else if (kmemleak_early_log) - log_early(KMEMLEAK_ALLOC, ptr, size, min_count); } EXPORT_SYMBOL_GPL(kmemleak_alloc); @@ -1028,8 +912,6 @@ void __ref kmemleak_alloc_percpu(const void __percpu *ptr, size_t size, for_each_possible_cpu(cpu) create_object((unsigned long)per_cpu_ptr(ptr, cpu), size, 0, gfp); - else if (kmemleak_early_log) - log_early(KMEMLEAK_ALLOC_PERCPU, ptr, size, 0); } EXPORT_SYMBOL_GPL(kmemleak_alloc_percpu); @@ -1054,11 +936,6 @@ void __ref kmemleak_vmalloc(const struct vm_struct *area, size_t size, gfp_t gfp create_object((unsigned long)area->addr, size, 2, gfp); object_set_excess_ref((unsigned long)area, (unsigned long)area->addr); - } else if (kmemleak_early_log) { - log_early(KMEMLEAK_ALLOC, area->addr, size, 2); - /* reusing early_log.size for storing area->addr */ - log_early(KMEMLEAK_SET_EXCESS_REF, - area, (unsigned long)area->addr, 0); } } EXPORT_SYMBOL_GPL(kmemleak_vmalloc); @@ -1076,8 +953,6 @@ void __ref kmemleak_free(const void *ptr) if (kmemleak_free_enabled && ptr && !IS_ERR(ptr)) delete_object_full((unsigned long)ptr); - else if (kmemleak_early_log) - log_early(KMEMLEAK_FREE, ptr, 0, 0); } EXPORT_SYMBOL_GPL(kmemleak_free); @@ -1096,8 +971,6 @@ void __ref kmemleak_free_part(const void *ptr, size_t size) if (kmemleak_enabled && ptr && !IS_ERR(ptr)) delete_object_part((unsigned long)ptr, size); - else if (kmemleak_early_log) - log_early(KMEMLEAK_FREE_PART, ptr, size, 0); } EXPORT_SYMBOL_GPL(kmemleak_free_part); @@ -1118,8 +991,6 @@ void __ref kmemleak_free_percpu(const void __percpu *ptr) for_each_possible_cpu(cpu) delete_object_full((unsigned long)per_cpu_ptr(ptr, cpu)); - else if (kmemleak_early_log) - log_early(KMEMLEAK_FREE_PERCPU, ptr, 0, 0); } EXPORT_SYMBOL_GPL(kmemleak_free_percpu); @@ -1170,8 +1041,6 @@ void __ref kmemleak_not_leak(const void *ptr) if (kmemleak_enabled && ptr && !IS_ERR(ptr)) make_gray_object((unsigned long)ptr); - else if (kmemleak_early_log) - log_early(KMEMLEAK_NOT_LEAK, ptr, 0, 0); } EXPORT_SYMBOL(kmemleak_not_leak); @@ -1190,8 +1059,6 @@ void __ref kmemleak_ignore(const void *ptr) if (kmemleak_enabled && ptr && !IS_ERR(ptr)) make_black_object((unsigned long)ptr); - else if (kmemleak_early_log) - log_early(KMEMLEAK_IGNORE, ptr, 0, 0); } EXPORT_SYMBOL(kmemleak_ignore); @@ -1212,8 +1079,6 @@ void __ref kmemleak_scan_area(const void *ptr, size_t size, gfp_t gfp) if (kmemleak_enabled && ptr && size && !IS_ERR(ptr)) add_scan_area((unsigned long)ptr, size, gfp); - else if (kmemleak_early_log) - log_early(KMEMLEAK_SCAN_AREA, ptr, size, 0); } EXPORT_SYMBOL(kmemleak_scan_area); @@ -1232,8 +1097,6 @@ void __ref kmemleak_no_scan(const void *ptr) if (kmemleak_enabled && ptr && !IS_ERR(ptr)) object_no_scan((unsigned long)ptr); - else if (kmemleak_early_log) - log_early(KMEMLEAK_NO_SCAN, ptr, 0, 0); } EXPORT_SYMBOL(kmemleak_no_scan); @@ -2020,7 +1883,6 @@ static void kmemleak_disable(void) /* stop any memory operation tracing */ kmemleak_enabled = 0; - kmemleak_early_log = 0; /* check whether it is too early for a kernel thread */ if (kmemleak_initialized) @@ -2048,20 +1910,11 @@ static int __init kmemleak_boot_config(char *str) } early_param("kmemleak", kmemleak_boot_config); -static void __init print_log_trace(struct early_log *log) -{ - pr_notice("Early log backtrace:\n"); - stack_trace_print(log->trace, log->trace_len, 2); -} - /* * Kmemleak initialization. */ void __init kmemleak_init(void) { - int i; - unsigned long flags; - #ifdef CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF if (!kmemleak_skip_disable) { kmemleak_disable(); @@ -2069,28 +1922,15 @@ void __init kmemleak_init(void) } #endif + if (kmemleak_error) + return; + jiffies_min_age = msecs_to_jiffies(MSECS_MIN_AGE); jiffies_scan_wait = msecs_to_jiffies(SECS_SCAN_WAIT * 1000); object_cache = KMEM_CACHE(kmemleak_object, SLAB_NOLEAKTRACE); scan_area_cache = KMEM_CACHE(kmemleak_scan_area, SLAB_NOLEAKTRACE); - if (crt_early_log > ARRAY_SIZE(early_log)) - pr_warn("Early log buffer exceeded (%d), please increase DEBUG_KMEMLEAK_EARLY_LOG_SIZE\n", - crt_early_log); - - /* the kernel is still in UP mode, so disabling the IRQs is enough */ - local_irq_save(flags); - kmemleak_early_log = 0; - if (kmemleak_error) { - local_irq_restore(flags); - return; - } else { - kmemleak_enabled = 1; - kmemleak_free_enabled = 1; - } - local_irq_restore(flags); - /* register the data/bss sections */ create_object((unsigned long)_sdata, _edata - _sdata, KMEMLEAK_GREY, GFP_ATOMIC); @@ -2101,57 +1941,6 @@ void __init kmemleak_init(void) create_object((unsigned long)__start_ro_after_init, __end_ro_after_init - __start_ro_after_init, KMEMLEAK_GREY, GFP_ATOMIC); - - /* - * This is the point where tracking allocations is safe. Automatic - * scanning is started during the late initcall. Add the early logged - * callbacks to the kmemleak infrastructure. - */ - for (i = 0; i < crt_early_log; i++) { - struct early_log *log = &early_log[i]; - - switch (log->op_type) { - case KMEMLEAK_ALLOC: - early_alloc(log); - break; - case KMEMLEAK_ALLOC_PERCPU: - early_alloc_percpu(log); - break; - case KMEMLEAK_FREE: - kmemleak_free(log->ptr); - break; - case KMEMLEAK_FREE_PART: - kmemleak_free_part(log->ptr, log->size); - break; - case KMEMLEAK_FREE_PERCPU: - kmemleak_free_percpu(log->ptr); - break; - case KMEMLEAK_NOT_LEAK: - kmemleak_not_leak(log->ptr); - break; - case KMEMLEAK_IGNORE: - kmemleak_ignore(log->ptr); - break; - case KMEMLEAK_SCAN_AREA: - kmemleak_scan_area(log->ptr, log->size, GFP_KERNEL); - break; - case KMEMLEAK_NO_SCAN: - kmemleak_no_scan(log->ptr); - break; - case KMEMLEAK_SET_EXCESS_REF: - object_set_excess_ref((unsigned long)log->ptr, - log->excess_ref); - break; - default: - kmemleak_warn("Unknown early log operation: %d\n", - log->op_type); - } - - if (kmemleak_warning) { - print_log_trace(log); - kmemleak_warning = 0; - } - } } /*