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=-17.4 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_IN_DEF_DKIM_WL 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 1297BC00A89 for ; Fri, 30 Oct 2020 19:30:27 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 1930F206E3 for ; Fri, 30 Oct 2020 19:30:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="iaEVNbKj" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1930F206E3 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 508DC6B0036; Fri, 30 Oct 2020 15:30:25 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 4BA026B005C; Fri, 30 Oct 2020 15:30:25 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 381DB6B005D; Fri, 30 Oct 2020 15:30:25 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0104.hostedemail.com [216.40.44.104]) by kanga.kvack.org (Postfix) with ESMTP id 005EF6B0036 for ; Fri, 30 Oct 2020 15:30:24 -0400 (EDT) Received: from smtpin04.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id A0AD53622 for ; Fri, 30 Oct 2020 19:30:24 +0000 (UTC) X-FDA: 77429583168.04.bike49_3d081ff27298 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin04.hostedemail.com (Postfix) with ESMTP id 8217B800294A for ; Fri, 30 Oct 2020 19:30:24 +0000 (UTC) X-HE-Tag: bike49_3d081ff27298 X-Filterd-Recvd-Size: 21449 Received: from mail-pf1-f195.google.com (mail-pf1-f195.google.com [209.85.210.195]) by imf50.hostedemail.com (Postfix) with ESMTP for ; Fri, 30 Oct 2020 19:30:23 +0000 (UTC) Received: by mail-pf1-f195.google.com with SMTP id x13so6157395pfa.9 for ; Fri, 30 Oct 2020 12:30:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=uCxbrB8kOGB154Lx7US6rz7YBkrXxfF/uMObBntK2wE=; b=iaEVNbKjYYsphfDHCTTTuzyio44ceisdcr/1+so+eIwVqHnCeqdkDtsRoCLK1x+ofb 8rJMxcEAKcfp/YnPzX9rqNNlQqrzKQ8oYTOHwcxkwvZkJ/RtRekC/sHHJx8VR7JNNLRU DRfSfkAQyAA00G7vB9jICikCfbLsnoz8pwtYxe/IDrNxf6j5SzJH8UrkdD5KFr4SCXlN /E/OiVX4uAXoneuTvTojNTLrYfsOTrjkMxxBQEMKU7Rwq58yoYX/SJ206mHQK/vnviow +UpQMuUJAgLWUqrscXdSiZcCC54bfcMOOQjaNQhiE8k00Ra6IVvtyIeHDJbUmQb67+e2 aeKw== 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=uCxbrB8kOGB154Lx7US6rz7YBkrXxfF/uMObBntK2wE=; b=E4JW2Nv4CY68JsV6A9/1RUIWiOiV4veRoV4/NqyL9+A4UyFvYmbZa5TUjNg5Nt6tBg ygexHTI+xfA5n5u3O76zwWdUecMUbweeupexA/wMLVQW3yvP30JNZ57q7GtP015y7CIy K8UVEhy7zqfgiDRdejJu1vRWb3KEcKe0f+8jtCQqvd1NwkhON9IYE2+PrQkf8SksySHz 5x0Jt72Xi7m76PLYUD9X6YIUJYX5+/xDppATJu/qJ8EIOgpZxOOKruzJ4SfQEpjpWrC5 TP5FQrk8R+TjpnnkW9LiivEtKdTS11pX5ZUfb6kb7LpnqntcgXRuiFGVb2tTGnkaonk2 jBZg== X-Gm-Message-State: AOAM531LAPAUAUbDI+282JYIm662AOcLSU42oc57t8d2DYwTqafXAdpP t7YinuP8CxOa3MXGFEueegzua/tSo9u4Y5tCJcIi2Q== X-Google-Smtp-Source: ABdhPJzh1ZPrbxIIQUVPPpHZtvLDVweemyPay8lYEGnU2i5v9I/m9fZcFBj0RYXr4v2W750gnWkRFwvh75rvFzRPysI= X-Received: by 2002:a63:d456:: with SMTP id i22mr3465961pgj.440.1604086222271; Fri, 30 Oct 2020 12:30:22 -0700 (PDT) MIME-Version: 1.0 References: <6a4a7626bf280871518656f4fa89cb064740baf7.1603372719.git.andreyknvl@google.com> In-Reply-To: From: Andrey Konovalov Date: Fri, 30 Oct 2020 20:30:11 +0100 Message-ID: Subject: Re: [PATCH RFC v2 14/21] kasan: add and integrate kasan boot parameters To: Dmitry Vyukov Cc: Catalin Marinas , Will Deacon , Vincenzo Frascino , Alexander Potapenko , Marco Elver , Evgenii Stepanov , Kostya Serebryany , Peter Collingbourne , Serban Constantinescu , Andrey Ryabinin , Elena Petrova , Branislav Rankov , Kevin Brodsky , Andrew Morton , kasan-dev , Linux ARM , Linux-MM , LKML Content-Type: text/plain; charset="UTF-8" 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: On Wed, Oct 28, 2020 at 1:27 PM Dmitry Vyukov wrote: > > On Thu, Oct 22, 2020 at 3:19 PM Andrey Konovalov wrote: > > > > TODO: no meaningful description here yet, please see the cover letter > > for this RFC series. > > > > Signed-off-by: Andrey Konovalov > > Link: https://linux-review.googlesource.com/id/If7d37003875b2ed3e0935702c8015c223d6416a4 > > --- > > mm/kasan/common.c | 92 +++++++++++++----------- > > mm/kasan/generic.c | 5 ++ > > mm/kasan/hw_tags.c | 169 ++++++++++++++++++++++++++++++++++++++++++++- > > mm/kasan/kasan.h | 9 +++ > > mm/kasan/report.c | 14 +++- > > mm/kasan/sw_tags.c | 5 ++ > > 6 files changed, 250 insertions(+), 44 deletions(-) > > > > diff --git a/mm/kasan/common.c b/mm/kasan/common.c > > index 1a5e6c279a72..cc129ef62ab1 100644 > > --- a/mm/kasan/common.c > > +++ b/mm/kasan/common.c > > @@ -129,35 +129,37 @@ void kasan_cache_create(struct kmem_cache *cache, unsigned int *size, > > unsigned int redzone_size; > > int redzone_adjust; > > > > - /* Add alloc meta. */ > > - cache->kasan_info.alloc_meta_offset = *size; > > - *size += sizeof(struct kasan_alloc_meta); > > - > > - /* Add free meta. */ > > - if (IS_ENABLED(CONFIG_KASAN_GENERIC) && > > - (cache->flags & SLAB_TYPESAFE_BY_RCU || cache->ctor || > > - cache->object_size < sizeof(struct kasan_free_meta))) { > > - cache->kasan_info.free_meta_offset = *size; > > - *size += sizeof(struct kasan_free_meta); > > - } > > - > > - redzone_size = optimal_redzone(cache->object_size); > > - redzone_adjust = redzone_size - (*size - cache->object_size); > > - if (redzone_adjust > 0) > > - *size += redzone_adjust; > > - > > - *size = min_t(unsigned int, KMALLOC_MAX_SIZE, > > - max(*size, cache->object_size + redzone_size)); > > + if (static_branch_unlikely(&kasan_stack)) { > > Initially I thought kasan_stack is related to stack instrumentation. > And then wondered why we check it during slab creation. > I suggest giving it a slightly longer and more descriptive name. Will do. > ... reading code further, it also disables quarantine, right? > Something to mention somewhere. Quarantine is not supported for anything but generic KASAN. Maybe it makes sense to put this into documentation... > > + /* Add alloc meta. */ > > + cache->kasan_info.alloc_meta_offset = *size; > > + *size += sizeof(struct kasan_alloc_meta); > > + > > + /* Add free meta. */ > > + if (IS_ENABLED(CONFIG_KASAN_GENERIC) && > > + (cache->flags & SLAB_TYPESAFE_BY_RCU || cache->ctor || > > + cache->object_size < sizeof(struct kasan_free_meta))) { > > + cache->kasan_info.free_meta_offset = *size; > > + *size += sizeof(struct kasan_free_meta); > > + } > > > > - /* > > - * If the metadata doesn't fit, don't enable KASAN at all. > > - */ > > - if (*size <= cache->kasan_info.alloc_meta_offset || > > - *size <= cache->kasan_info.free_meta_offset) { > > - cache->kasan_info.alloc_meta_offset = 0; > > - cache->kasan_info.free_meta_offset = 0; > > - *size = orig_size; > > - return; > > + redzone_size = optimal_redzone(cache->object_size); > > + redzone_adjust = redzone_size - (*size - cache->object_size); > > + if (redzone_adjust > 0) > > + *size += redzone_adjust; > > + > > + *size = min_t(unsigned int, KMALLOC_MAX_SIZE, > > + max(*size, cache->object_size + redzone_size)); > > + > > + /* > > + * If the metadata doesn't fit, don't enable KASAN at all. > > + */ > > + if (*size <= cache->kasan_info.alloc_meta_offset || > > + *size <= cache->kasan_info.free_meta_offset) { > > + cache->kasan_info.alloc_meta_offset = 0; > > + cache->kasan_info.free_meta_offset = 0; > > + *size = orig_size; > > + return; > > + } > > } > > > > *flags |= SLAB_KASAN; > > @@ -165,10 +167,12 @@ void kasan_cache_create(struct kmem_cache *cache, unsigned int *size, > > > > size_t kasan_metadata_size(struct kmem_cache *cache) > > { > > - return (cache->kasan_info.alloc_meta_offset ? > > - sizeof(struct kasan_alloc_meta) : 0) + > > - (cache->kasan_info.free_meta_offset ? > > - sizeof(struct kasan_free_meta) : 0); > > + if (static_branch_unlikely(&kasan_stack)) > > + return (cache->kasan_info.alloc_meta_offset ? > > + sizeof(struct kasan_alloc_meta) : 0) + > > + (cache->kasan_info.free_meta_offset ? > > + sizeof(struct kasan_free_meta) : 0); > > + return 0; > > } > > > > struct kasan_alloc_meta *kasan_get_alloc_meta(struct kmem_cache *cache, > > @@ -270,8 +274,10 @@ void * __must_check kasan_init_slab_obj(struct kmem_cache *cache, > > if (!(cache->flags & SLAB_KASAN)) > > return (void *)object; > > > > - alloc_meta = kasan_get_alloc_meta(cache, object); > > - __memset(alloc_meta, 0, sizeof(*alloc_meta)); > > + if (static_branch_unlikely(&kasan_stack)) { > > Interestingly, now SLAB_KASAN is always set when kasan_stack is not > enabled. So it seems to me we can move the SLAB_KASAN check into this > unlikely branch now. Yes, will fix. I'll also include a complete rework of SLAB_KASAN into the next version. > > > + alloc_meta = kasan_get_alloc_meta(cache, object); > > + __memset(alloc_meta, 0, sizeof(*alloc_meta)); > > + } > > > > if (IS_ENABLED(CONFIG_KASAN_SW_TAGS) || IS_ENABLED(CONFIG_KASAN_HW_TAGS)) > > object = set_tag(object, assign_tag(cache, object, true, false)); > > @@ -308,15 +314,19 @@ static bool __kasan_slab_free(struct kmem_cache *cache, void *object, > > rounded_up_size = round_up(cache->object_size, KASAN_GRANULE_SIZE); > > kasan_poison_memory(object, rounded_up_size, KASAN_KMALLOC_FREE); > > > > - if ((IS_ENABLED(CONFIG_KASAN_GENERIC) && !quarantine) || > > - unlikely(!(cache->flags & SLAB_KASAN))) > > - return false; > > + if (static_branch_unlikely(&kasan_stack)) { > > + if ((IS_ENABLED(CONFIG_KASAN_GENERIC) && !quarantine) || > > + unlikely(!(cache->flags & SLAB_KASAN))) > > + return false; > > + > > + kasan_set_free_info(cache, object, tag); > > > > - kasan_set_free_info(cache, object, tag); > > + quarantine_put(cache, object); > > > > - quarantine_put(cache, object); > > + return IS_ENABLED(CONFIG_KASAN_GENERIC); > > + } > > > > - return IS_ENABLED(CONFIG_KASAN_GENERIC); > > + return false; > > } > > > > bool kasan_slab_free(struct kmem_cache *cache, void *object, unsigned long ip) > > @@ -355,7 +365,7 @@ static void *__kasan_kmalloc(struct kmem_cache *cache, const void *object, > > kasan_poison_memory((void *)redzone_start, redzone_end - redzone_start, > > KASAN_KMALLOC_REDZONE); > > > > - if (cache->flags & SLAB_KASAN) > > + if (static_branch_unlikely(&kasan_stack) && (cache->flags & SLAB_KASAN)) > > set_alloc_info(cache, (void *)object, flags); > > > > return set_tag(object, tag); > > diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c > > index d259e4c3aefd..20a1e753e0c5 100644 > > --- a/mm/kasan/generic.c > > +++ b/mm/kasan/generic.c > > @@ -33,6 +33,11 @@ > > #include "kasan.h" > > #include "../slab.h" > > > > +/* See the comments in hw_tags.c */ > > +DEFINE_STATIC_KEY_TRUE_RO(kasan_enabled); > > +EXPORT_SYMBOL(kasan_enabled); > > +DEFINE_STATIC_KEY_TRUE_RO(kasan_stack); > > + > > /* > > * All functions below always inlined so compiler could > > * perform better optimizations in each of __asan_loadX/__assn_storeX > > diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c > > index 915142da6b57..bccd781011ad 100644 > > --- a/mm/kasan/hw_tags.c > > +++ b/mm/kasan/hw_tags.c > > @@ -8,6 +8,8 @@ > > > > #define pr_fmt(fmt) "kasan: " fmt > > > > +#include > > +#include > > #include > > #include > > #include > > @@ -17,10 +19,175 @@ > > > > #include "kasan.h" > > > > +enum kasan_arg_mode { > > + KASAN_ARG_MODE_OFF, > > + KASAN_ARG_MODE_PROD, > > + KASAN_ARG_MODE_FULL, > > +}; > > + > > +enum kasan_arg_stack { > > + KASAN_ARG_STACK_DEFAULT, > > + KASAN_ARG_STACK_OFF, > > + KASAN_ARG_STACK_ON, > > +}; > > + > > +enum kasan_arg_trap { > > + KASAN_ARG_TRAP_DEFAULT, > > + KASAN_ARG_TRAP_ASYNC, > > + KASAN_ARG_TRAP_SYNC, > > +}; > > + > > +enum kasan_arg_fault { > > + KASAN_ARG_FAULT_DEFAULT, > > + KASAN_ARG_FAULT_REPORT, > > + KASAN_ARG_FAULT_PANIC, > > +}; > > + > > +static enum kasan_arg_mode kasan_arg_mode __ro_after_init; > > +static enum kasan_arg_stack kasan_arg_stack __ro_after_init; > > +static enum kasan_arg_fault kasan_arg_fault __ro_after_init; > > +static enum kasan_arg_trap kasan_arg_trap __ro_after_init; > > + > > +/* Whether KASAN is enabled at all. */ > > +DEFINE_STATIC_KEY_FALSE_RO(kasan_enabled); > > +EXPORT_SYMBOL(kasan_enabled); > > + > > +/* Whether to collect alloc/free stack traces. */ > > +DEFINE_STATIC_KEY_FALSE_RO(kasan_stack); > > + > > +/* Whether to use synchronous or asynchronous tag checking. */ > > +static bool kasan_sync __ro_after_init; > > + > > +/* Whether panic or disable tag checking on fault. */ > > +bool kasan_panic __ro_after_init; > > + > > +/* kasan.mode=off/prod/full */ > > +static int __init early_kasan_mode(char *arg) > > +{ > > + if (!arg) > > + return -EINVAL; > > + > > + if (!strcmp(arg, "off")) > > + kasan_arg_mode = KASAN_ARG_MODE_OFF; > > + else if (!strcmp(arg, "prod")) > > + kasan_arg_mode = KASAN_ARG_MODE_PROD; > > + else if (!strcmp(arg, "full")) > > + kasan_arg_mode = KASAN_ARG_MODE_FULL; > > + else > > + return -EINVAL; > > + > > + return 0; > > +} > > +early_param("kasan.mode", early_kasan_mode); > > + > > +/* kasan.stack=off/on */ > > +static int __init early_kasan_stack(char *arg) > > +{ > > + if (!arg) > > + return -EINVAL; > > + > > + if (!strcmp(arg, "off")) > > + kasan_arg_stack = KASAN_ARG_STACK_OFF; > > + else if (!strcmp(arg, "on")) > > + kasan_arg_stack = KASAN_ARG_STACK_ON; > > + else > > + return -EINVAL; > > + > > + return 0; > > +} > > +early_param("kasan.stack", early_kasan_stack); > > + > > +/* kasan.trap=sync/async */ > > +static int __init early_kasan_trap(char *arg) > > +{ > > + if (!arg) > > + return -EINVAL; > > + > > + if (!strcmp(arg, "ASYNC")) > > + kasan_arg_trap = KASAN_ARG_TRAP_ASYNC; > > + else if (!strcmp(arg, "sync")) > > + kasan_arg_trap = KASAN_ARG_TRAP_SYNC; > > + else > > + return -EINVAL; > > + > > + return 0; > > +} > > +early_param("kasan.trap", early_kasan_trap); > > + > > +/* kasan.fault=report/panic */ > > +static int __init early_kasan_fault(char *arg) > > +{ > > + if (!arg) > > + return -EINVAL; > > + > > + if (!strcmp(arg, "report")) > > + kasan_arg_fault = KASAN_ARG_FAULT_REPORT; > > + else if (!strcmp(arg, "panic")) > > + kasan_arg_fault = KASAN_ARG_FAULT_PANIC; > > + else > > + return -EINVAL; > > + > > + return 0; > > +} > > +early_param("kasan.fault", early_kasan_fault); > > + > > void __init kasan_init_tags(void) > > { > > - init_tags(KASAN_TAG_MAX); > > + if (!cpu_supports_tags()) > > + return; > > + > > + /* First, preset values based on the mode. */ > > + > > + switch (kasan_arg_mode) { > > + case KASAN_ARG_MODE_OFF: > > + return; > > + case KASAN_ARG_MODE_PROD: > > + static_branch_enable(&kasan_enabled); > > + break; > > + case KASAN_ARG_MODE_FULL: > > + static_branch_enable(&kasan_enabled); > > + static_branch_enable(&kasan_stack); > > + kasan_sync = true; > > + break; > > + } > > + > > + /* Now, optionally override the presets. */ > > > > + switch (kasan_arg_stack) { > > + case KASAN_ARG_STACK_OFF: > > + static_branch_disable(&kasan_stack); > > + break; > > + case KASAN_ARG_STACK_ON: > > + static_branch_enable(&kasan_stack); > > + break; > > + default: > > + break; > > + } > > + > > + switch (kasan_arg_trap) { > > + case KASAN_ARG_TRAP_ASYNC: > > + kasan_sync = false; > > + break; > > + case KASAN_ARG_TRAP_SYNC: > > + kasan_sync = true; > > + break; > > + default: > > + break; > > + } > > + > > + switch (kasan_arg_fault) { > > + case KASAN_ARG_FAULT_REPORT: > > + kasan_panic = false; > > + break; > > + case KASAN_ARG_FAULT_PANIC: > > + kasan_panic = true; > > + break; > > + default: > > + break; > > + } > > + > > + /* TODO: choose between sync and async based on kasan_sync. */ > > + init_tags(KASAN_TAG_MAX); > > pr_info("KernelAddressSanitizer initialized\n"); > > } > > > > diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h > > index f7ae0c23f023..00b47bc753aa 100644 > > --- a/mm/kasan/kasan.h > > +++ b/mm/kasan/kasan.h > > @@ -2,9 +2,18 @@ > > #ifndef __MM_KASAN_KASAN_H > > #define __MM_KASAN_KASAN_H > > > > +#include > > #include > > #include > > > > +#ifdef CONFIG_KASAN_HW_TAGS > > +DECLARE_STATIC_KEY_FALSE(kasan_stack); > > +#else > > +DECLARE_STATIC_KEY_TRUE(kasan_stack); > > +#endif > > kasan_stack and kasan_enabled make sense and changed only in hw_tags mode. > It would be cleaner (and faster for other modes) to abstract static keys as: > > #ifdef CONFIG_KASAN_HW_TAGS > #include > DECLARE_STATIC_KEY_FALSE(kasan_stack); > static inline bool kasan_stack_collection_enabled() > { > return static_branch_unlikely(&kasan_stack); > } > #else > static inline bool kasan_stack_collection_enabled() { return true; } > #endif > > This way we don't need to include and define static keys for other modes. Sounds good, will do. > > > +extern bool kasan_panic __ro_after_init; > > + > > #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS) > > #define KASAN_GRANULE_SIZE (1UL << KASAN_SHADOW_SCALE_SHIFT) > > #else > > diff --git a/mm/kasan/report.c b/mm/kasan/report.c > > index dee5350b459c..426dd1962d3c 100644 > > --- a/mm/kasan/report.c > > +++ b/mm/kasan/report.c > > @@ -97,6 +97,10 @@ static void end_report(unsigned long *flags) > > panic_on_warn = 0; > > panic("panic_on_warn set ...\n"); > > } > > +#ifdef CONFIG_KASAN_HW_TAGS > > + if (kasan_panic) > > + panic("kasan.fault=panic set ...\n"); > > +#endif > > kasan_enable_current(); > > } > > > > @@ -159,8 +163,8 @@ static void describe_object_addr(struct kmem_cache *cache, void *object, > > (void *)(object_addr + cache->object_size)); > > } > > > > -static void describe_object(struct kmem_cache *cache, void *object, > > - const void *addr, u8 tag) > > +static void describe_object_stacks(struct kmem_cache *cache, void *object, > > + const void *addr, u8 tag) > > { > > struct kasan_alloc_meta *alloc_meta = kasan_get_alloc_meta(cache, object); > > > > @@ -188,7 +192,13 @@ static void describe_object(struct kmem_cache *cache, void *object, > > } > > #endif > > } > > +} > > > > +static void describe_object(struct kmem_cache *cache, void *object, > > + const void *addr, u8 tag) > > +{ > > + if (static_branch_unlikely(&kasan_stack)) > > + describe_object_stacks(cache, object, addr, tag); > > describe_object_addr(cache, object, addr); > > } > > > > diff --git a/mm/kasan/sw_tags.c b/mm/kasan/sw_tags.c > > index 4db41f274702..b6d185adf2c5 100644 > > --- a/mm/kasan/sw_tags.c > > +++ b/mm/kasan/sw_tags.c > > @@ -33,6 +33,11 @@ > > #include "kasan.h" > > #include "../slab.h" > > > > +/* See the comments in hw_tags.c */ > > +DEFINE_STATIC_KEY_TRUE_RO(kasan_enabled); > > +EXPORT_SYMBOL(kasan_enabled); > > +DEFINE_STATIC_KEY_TRUE_RO(kasan_stack); > > + > > static DEFINE_PER_CPU(u32, prng_state); > > > > void __init kasan_init_tags(void) > > -- > > 2.29.0.rc1.297.gfa9743e501-goog > >