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Fri, 5 Dec 2025 07:20:51 +0000 (UTC) Received: from localhost (unknown [10.72.112.128]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id ADBA01953986; Fri, 5 Dec 2025 07:20:50 +0000 (UTC) Date: Fri, 5 Dec 2025 15:20:46 +0800 From: Baoquan He To: Andrey Konovalov Cc: linux-mm@kvack.org, ryabinin.a.a@gmail.com, glider@google.com, dvyukov@google.com, vincenzo.frascino@arm.com, akpm@linux-foundation.org, kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org, kexec@lists.infradead.org, elver@google.com, sj@kernel.org, lorenzo.stoakes@oracle.com, snovitoll@gmail.com, christophe.leroy@csgroup.eu Subject: Re: [PATCH v4 01/12] mm/kasan: add conditional checks in functions to return directly if kasan is disabled Message-ID: References: <20251128033320.1349620-1-bhe@redhat.com> <20251128033320.1349620-2-bhe@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 X-Rspam-User: X-Rspamd-Queue-Id: 05A4620004 X-Rspamd-Server: rspam11 X-Stat-Signature: kw3d69dggsxmse6x44sxt7epsa1srm5f X-HE-Tag: 1764919260-273518 X-HE-Meta: U2FsdGVkX19mKiYo0bdP4T2f4D+Cx4Xkgm6B1H4ETobqR6dbuM7aR0UoTFGdRH1I7OEyRWKKzY0OeerzpdrZBQRyT4Xj6rBP3Ai0KBtVmGoVpqtkhK+JwgVGbb6dq0DFgdMRMfFZPxfofGBOOkNqZLXcmamIVyihlaLFx06CbFFMZdnWl3pNFPG4h/J459JjX8ab216W+vxxpgUGKQqCFf79H9anwWK3h6CK6Kt+RonmetlfxPI2INk8xjP56SKtRz5iyhqIjja5UmVV+AFuTJZMxGTtCsW9Q4Fm+W8+5TL6ZSVdK1WMEpLMuML70XtccEu1fndQdh62CLNfPKG/KIL1Jm9CE4bOHVsmCRMoLrXhSttPBORRYbAOgWddlcPEB8hloSqpIYWYx53bQ89d+k+L0wxfDhHqPyEUSlcIBxe/XjGRzabMxXTle86RDCIik6c2Ue+egXmNHw50PLimBZN6ZG/eTkSb1NpsH3qdINUayQc9zEGO9EgbqJwnZiVKTaVXXS7nF3WtYmnn7hg43wfWemxU026s3InmIjZPG5p500BBV2fYQOQCDznKzA5xLpTyCSqtp6J7HoXy5wkue7zvI07uxtHy6Zs7iapysF5CSMef4HfANmyTW1I/0v8XxAkDpp6KAbeu2A2Su50wYzH9ex/NK+YaZpOg9oWz+34IqGHfnPajlACBPKkz1b9KwL3P4w7aufzTPcCNi2hiAGjh19adFko2Zb866xuGNP+1iah0ydL5Rn6Qcz/ta2pAdA+xrXGpxNGc0twsp+BqinZwwgEpExfxdItGefbpF647Le3HfagFOjRVqxryPyurBWoGF0P7mDAuBKiMpZBIqWB2Kw0ju/RRaayUYPeixUD0+e8fOx3Y0+Cfb4huXnxdENnT8FBwNEqJVClmoMhS59CL+WF0+DwgRevl93Fgt7/LB+ZFu9QGbyqD6JaLbDGEfslErD/MHQvHYvhWMUO XyQJ2jeV Z9LpxbtdcDJGE3+DG30LPLJWggnqMBNG//iqFFIw5dEPfYYbr3HYzcuhXf5imFi3APkoC74Z4mAPe40WPy/Fw1eggO6yub8vPm63deMl/mtG/9sHPwHLrvQY9D+ufX71hRVA6PLhQ4AAXYYIiApJ4qJVigS6GcFvfE1wRBT+e+zM7DJZsMA5s9PwMQKZXrdcD67CicEiFRVGoOkb2o/+xrwkAtpQw2FjarxLFy2bqVN7orUbzQSHjBfO+Qhrhyq+hjo/ttP0UEFPB7pSCAj4B8pKbn6ulDJzxatQCpGnoRXBrmm3RAt3xwlk1Rs+8QMaBsGra+kv86bp+L3F54pvnwV3zHSK9iRJTItyh+MW/1QkikkjX4D9smwE/KR+IV8NgRmL+V/IiaqVOsCj0H4OrEpoPgm0CHnt0ClORiJskuroCDitv3ckgaOB9j9pdnpUtvtXYVGY1a70d9QBayrvsPGrj13NupwGambJR 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: List-Subscribe: List-Unsubscribe: On 12/04/25 at 05:38pm, Andrey Konovalov wrote: > On Fri, Nov 28, 2025 at 4:33 AM Baoquan He wrote: > > > > The current codes only check if kasan is disabled for hw_tags > > mode. Here add the conditional checks for functional functions of > > generic mode and sw_tags mode. > > > > This is prepared for later adding kernel parameter kasan=on|off for > > all three kasan modes. > > > > Signed-off-by: Baoquan He > > --- > > mm/kasan/generic.c | 17 +++++++++++++++-- > > mm/kasan/init.c | 6 ++++++ > > mm/kasan/quarantine.c | 3 +++ > > mm/kasan/report.c | 4 +++- > > mm/kasan/shadow.c | 11 ++++++++++- > > mm/kasan/sw_tags.c | 3 +++ > > 6 files changed, 40 insertions(+), 4 deletions(-) > > > > diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c > > index 2b8e73f5f6a7..aff822aa2bd6 100644 > > --- a/mm/kasan/generic.c > > +++ b/mm/kasan/generic.c > > @@ -214,12 +214,13 @@ bool kasan_byte_accessible(const void *addr) > > > > void kasan_cache_shrink(struct kmem_cache *cache) > > { > > - kasan_quarantine_remove_cache(cache); > > + if (kasan_enabled()) > > Please move these checks to include/linux/kasan.h and add __helpers to > consistent with how it's done for other KASAN annotation calls. > Otherwise eventually these checks start creeping into lower level > functions and the logic of checking when and whether KASAN is enabled > becomes a mess. Not sure if I got it correctly. Are you suggesting it should be done like kasan_populate_vmalloc()/__kasan_populate_vmalloc(), kasan_release_vmalloc()/__kasan_release_vmalloc()? > > > > > + kasan_quarantine_remove_cache(cache); > > } > > > > void kasan_cache_shutdown(struct kmem_cache *cache) > > { > > - if (!__kmem_cache_empty(cache)) > > + if (kasan_enabled() && !__kmem_cache_empty(cache)) > > kasan_quarantine_remove_cache(cache); > > } > > > > @@ -239,6 +240,9 @@ void __asan_register_globals(void *ptr, ssize_t size) > > int i; > > struct kasan_global *globals = ptr; > > > > + if (!kasan_enabled()) > > + return; > > + > > for (i = 0; i < size; i++) > > register_global(&globals[i]); > > } > > @@ -369,6 +373,9 @@ void kasan_cache_create(struct kmem_cache *cache, unsigned int *size, > > unsigned int rem_free_meta_size; > > unsigned int orig_alloc_meta_offset; > > > > + if (!kasan_enabled()) > > + return; > > + > > if (!kasan_requires_meta()) > > return; > > > > @@ -518,6 +525,9 @@ size_t kasan_metadata_size(struct kmem_cache *cache, bool in_object) > > { > > struct kasan_cache *info = &cache->kasan_info; > > > > + if (!kasan_enabled()) > > + return 0; > > + > > if (!kasan_requires_meta()) > > return 0; > > > > @@ -543,6 +553,9 @@ void kasan_record_aux_stack(void *addr) > > struct kasan_alloc_meta *alloc_meta; > > void *object; > > > > + if (!kasan_enabled()) > > + return; > > + > > if (is_kfence_address(addr) || !slab) > > return; > > > > diff --git a/mm/kasan/init.c b/mm/kasan/init.c > > index f084e7a5df1e..c78d77ed47bc 100644 > > --- a/mm/kasan/init.c > > +++ b/mm/kasan/init.c > > @@ -447,6 +447,9 @@ void kasan_remove_zero_shadow(void *start, unsigned long size) > > unsigned long addr, end, next; > > pgd_t *pgd; > > > > + if (!kasan_enabled()) > > + return; > > + > > addr = (unsigned long)kasan_mem_to_shadow(start); > > end = addr + (size >> KASAN_SHADOW_SCALE_SHIFT); > > > > @@ -482,6 +485,9 @@ int kasan_add_zero_shadow(void *start, unsigned long size) > > int ret; > > void *shadow_start, *shadow_end; > > > > + if (!kasan_enabled()) > > + return 0; > > + > > shadow_start = kasan_mem_to_shadow(start); > > shadow_end = shadow_start + (size >> KASAN_SHADOW_SCALE_SHIFT); > > > > diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c > > index 6958aa713c67..a6dc2c3d8a15 100644 > > --- a/mm/kasan/quarantine.c > > +++ b/mm/kasan/quarantine.c > > @@ -405,6 +405,9 @@ static int __init kasan_cpu_quarantine_init(void) > > { > > int ret = 0; > > > > + if (!kasan_enabled()) > > + return 0; > > + > > ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "mm/kasan:online", > > kasan_cpu_online, kasan_cpu_offline); > > if (ret < 0) > > diff --git a/mm/kasan/report.c b/mm/kasan/report.c > > index 62c01b4527eb..884357fa74ed 100644 > > --- a/mm/kasan/report.c > > +++ b/mm/kasan/report.c > > @@ -576,7 +576,9 @@ bool kasan_report(const void *addr, size_t size, bool is_write, > > unsigned long irq_flags; > > struct kasan_report_info info; > > > > - if (unlikely(report_suppressed_sw()) || unlikely(!report_enabled())) { > > + if (unlikely(report_suppressed_sw()) || > > + unlikely(!report_enabled()) || > > + !kasan_enabled()) { > > ret = false; > > goto out; > > } > > diff --git a/mm/kasan/shadow.c b/mm/kasan/shadow.c > > index 29a751a8a08d..f73a691421de 100644 > > --- a/mm/kasan/shadow.c > > +++ b/mm/kasan/shadow.c > > @@ -164,6 +164,8 @@ void kasan_unpoison(const void *addr, size_t size, bool init) > > { > > u8 tag = get_tag(addr); > > > > + if (!kasan_enabled()) > > + return; > > /* > > * Perform shadow offset calculation based on untagged address, as > > * some of the callers (e.g. kasan_unpoison_new_object) pass tagged > > @@ -277,7 +279,8 @@ static int __meminit kasan_mem_notifier(struct notifier_block *nb, > > > > static int __init kasan_memhotplug_init(void) > > { > > - hotplug_memory_notifier(kasan_mem_notifier, DEFAULT_CALLBACK_PRI); > > + if (kasan_enabled()) > > + hotplug_memory_notifier(kasan_mem_notifier, DEFAULT_CALLBACK_PRI); > > > > return 0; > > } > > @@ -658,6 +661,9 @@ int kasan_alloc_module_shadow(void *addr, size_t size, gfp_t gfp_mask) > > size_t shadow_size; > > unsigned long shadow_start; > > > > + if (!kasan_enabled()) > > + return 0; > > + > > shadow_start = (unsigned long)kasan_mem_to_shadow(addr); > > scaled_size = (size + KASAN_GRANULE_SIZE - 1) >> > > KASAN_SHADOW_SCALE_SHIFT; > > @@ -694,6 +700,9 @@ int kasan_alloc_module_shadow(void *addr, size_t size, gfp_t gfp_mask) > > > > void kasan_free_module_shadow(const struct vm_struct *vm) > > { > > + if (!kasan_enabled()) > > + return; > > + > > if (IS_ENABLED(CONFIG_UML)) > > return; > > > > diff --git a/mm/kasan/sw_tags.c b/mm/kasan/sw_tags.c > > index c75741a74602..6c1caec4261a 100644 > > --- a/mm/kasan/sw_tags.c > > +++ b/mm/kasan/sw_tags.c > > @@ -79,6 +79,9 @@ bool kasan_check_range(const void *addr, size_t size, bool write, > > u8 *shadow_first, *shadow_last, *shadow; > > void *untagged_addr; > > > > + if (!kasan_enabled()) > > + return true; > > + > > if (unlikely(size == 0)) > > return true; > > > > -- > > 2.41.0 > > >