From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 53EAF23371B for ; Fri, 5 Dec 2025 07:21:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764919270; cv=none; b=dn0h1+Lf2TQ3bDGyhMFN8tGDyaA3aTg1sZ34YcsrkIaaFhej+56ZhVCPMkXgM185fEQhEyODrm7kfos/OedWQg0mF3r4Mr/lwsIZqnRLlpiLSEglbnmZ5rNP7qD7lXPbPODGZI+7ga3Gc9RkWP7LFz8oOvO5EbIgVlZhQGOu2ps= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764919270; c=relaxed/simple; bh=8xlN+diys6LVYd7q6O7XIZ3pG82A7BrVpYirVKPWp5I=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=bNR+tmwXzFz1gthv7q/FO/29rHt66OJbil7Zw3ZsEkToH8LrNSK5fSsZ29DeZ9US5ONhUipQuyJ3NlFNUJ6UZ8vL+AxqNS7NPaBd/Q0U0OlBRXeR5S7jHEUjAjXdb/pmnEa5zNWLsfnGAyufywv1zPba97xCtrQsXOugUnp8Lyg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=YV9j7vkD; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="YV9j7vkD" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1764919258; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Qz0Looyy1EKTh6igJJhb5SyOqLVdyy67umD/p6pJLsU=; b=YV9j7vkDnOUUZC7VjM1KqiPcQbZ8AsVEFuN1q4Hww2XW4NqTY+1irtthpRawGkNWRdNO1G nLIjGOlmTQJov+b5Ri2NuSILz56kXaAwQDdn+TAegHo4y79os+3J6ddRUITWWA2KmpyO8t 73kTBQ6O3A8UOBVqNZTKkGmd/syj1Bg= Received: from mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-433-SWZoQuqHO1mLKMvsCtHm1A-1; Fri, 05 Dec 2025 02:20:54 -0500 X-MC-Unique: SWZoQuqHO1mLKMvsCtHm1A-1 X-Mimecast-MFC-AGG-ID: SWZoQuqHO1mLKMvsCtHm1A_1764919252 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id EBD551956055; 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> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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 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 > > >