From nobody Sun Oct 5 12:46:56 2025 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 8321B21ABDB for ; Tue, 5 Aug 2025 06:24:08 +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=1754375050; cv=none; b=jQzDa+aWJJyMKSSk/5hB/1oQQLdGwUPt9Wrep9X4X+XC4UwG2MKWFmx4kBh8kW3bHhdsPsJcXmg0mRCjbOmpL5cp6LLZlJeU1yKNvu2pilYQiekQL7c+X8efVRNiVN1GMseGX10UQXZY5ICPNtdJLVC3Vs+IzzxG1OJSgsIwzJQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754375050; c=relaxed/simple; bh=lZ+OKkIOkFuedEaabW32pjJAl9o7rxnfTpjfeGfsgDY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-type; b=InuKzErvDhj0Xjjgg5q1KqunOUajzzsBA0vUuAa2R93YL0vnIBb/W3hT2vYYOf0vuY/SJO7TYvnndK2sI6auWv56pRCAXUdRiYV7qgXaVej6r/bBlZT1aqlOCAc0LowYQHo0kl1+N2wCasguuvjLmUzQXr6rLFRQMZ81ncEWNfU= 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=gv5JyxEV; 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="gv5JyxEV" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1754375047; 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=c+hY2uT3rtX0jxqTDwr4o0wnNu5PQr3WJ9i3CgsATwQ=; b=gv5JyxEVKqU1++p8yFiJfgtVZ+ZlJ572dpVtrDyj1qTF7eIfubCmho+XYwM5xFkpZw5eym di3wPUbmEa/+0/6EYtIpwPPrF/3ICMj/7bACfvQeRtedAkhlcWwj9qam1kcybNrdzn5g8L 9yynk81A74fWtA1YWifPC0ZCy1q96J4= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-357-zuByUt8SMlOb-KzlFOuhUA-1; Tue, 05 Aug 2025 02:24:03 -0400 X-MC-Unique: zuByUt8SMlOb-KzlFOuhUA-1 X-Mimecast-MFC-AGG-ID: zuByUt8SMlOb-KzlFOuhUA_1754375041 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-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 8C4B71800366; Tue, 5 Aug 2025 06:24:01 +0000 (UTC) Received: from MiWiFi-R3L-srv.redhat.com (unknown [10.72.112.136]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 55DDF1956094; Tue, 5 Aug 2025 06:23:55 +0000 (UTC) From: Baoquan He To: linux-mm@kvack.org Cc: ryabinin.a.a@gmail.com, glider@google.com, andreyknvl@gmail.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, Baoquan He Subject: [PATCH 3/4] mm/kasan: don't initialize kasan if it's disabled Date: Tue, 5 Aug 2025 14:23:32 +0800 Message-ID: <20250805062333.121553-4-bhe@redhat.com> In-Reply-To: <20250805062333.121553-1-bhe@redhat.com> References: <20250805062333.121553-1-bhe@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 Content-Type: text/plain; charset="utf-8" This is mainly done in all architectures which support kasan, and also need be done in sw_tags init funciton kasan_init_sw_tags(). And also add code to enable kasan_flag_enabled, this is for later usage. Signed-off-by: Baoquan He --- arch/arm/mm/kasan_init.c | 6 ++++++ arch/arm64/mm/kasan_init.c | 7 +++++++ arch/loongarch/mm/kasan_init.c | 5 +++++ arch/powerpc/mm/kasan/init_32.c | 8 +++++++- arch/powerpc/mm/kasan/init_book3e_64.c | 6 ++++++ arch/powerpc/mm/kasan/init_book3s_64.c | 6 ++++++ arch/riscv/mm/kasan_init.c | 6 ++++++ arch/um/kernel/mem.c | 6 ++++++ arch/x86/mm/kasan_init_64.c | 6 ++++++ arch/xtensa/mm/kasan_init.c | 6 ++++++ mm/kasan/sw_tags.c | 6 ++++++ 11 files changed, 67 insertions(+), 1 deletion(-) diff --git a/arch/arm/mm/kasan_init.c b/arch/arm/mm/kasan_init.c index 111d4f703136..c764e1b9c9c5 100644 --- a/arch/arm/mm/kasan_init.c +++ b/arch/arm/mm/kasan_init.c @@ -212,6 +212,8 @@ void __init kasan_init(void) phys_addr_t pa_start, pa_end; u64 i; =20 + if (kasan_arg_disabled) + return; /* * We are going to perform proper setup of shadow memory. * @@ -300,6 +302,10 @@ void __init kasan_init(void) local_flush_tlb_all(); =20 memset(kasan_early_shadow_page, 0, PAGE_SIZE); + + /* KASAN is now initialized, enable it. */ + static_branch_enable(&kasan_flag_enabled); + pr_info("Kernel address sanitizer initialized\n"); init_task.kasan_depth =3D 0; } diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c index d541ce45daeb..0e4ffe3f5d0e 100644 --- a/arch/arm64/mm/kasan_init.c +++ b/arch/arm64/mm/kasan_init.c @@ -384,6 +384,9 @@ void __init kasan_populate_early_vm_area_shadow(void *s= tart, unsigned long size) { unsigned long shadow_start, shadow_end; =20 + if (!kasan_enabled()) + return; + if (!is_vmalloc_or_module_addr(start)) return; =20 @@ -397,6 +400,9 @@ void __init kasan_populate_early_vm_area_shadow(void *s= tart, unsigned long size) =20 void __init kasan_init(void) { + if (kasan_arg_disabled) + return; + kasan_init_shadow(); kasan_init_depth(); #if defined(CONFIG_KASAN_GENERIC) @@ -405,6 +411,7 @@ void __init kasan_init(void) * Software and Hardware Tag-Based modes still require * kasan_init_sw_tags() and kasan_init_hw_tags() correspondingly. */ + static_branch_enable(&kasan_flag_enabled); pr_info("KernelAddressSanitizer initialized (generic)\n"); #endif } diff --git a/arch/loongarch/mm/kasan_init.c b/arch/loongarch/mm/kasan_init.c index d2681272d8f0..0c32eee6910f 100644 --- a/arch/loongarch/mm/kasan_init.c +++ b/arch/loongarch/mm/kasan_init.c @@ -267,6 +267,8 @@ void __init kasan_init(void) u64 i; phys_addr_t pa_start, pa_end; =20 + if (kasan_arg_disabled) + return; /* * If PGDIR_SIZE is too large for cpu_vabits, KASAN_SHADOW_END will * overflow UINTPTR_MAX and then looks like a user space address. @@ -327,6 +329,9 @@ void __init kasan_init(void) csr_write64(__pa_symbol(swapper_pg_dir), LOONGARCH_CSR_PGDH); local_flush_tlb_all(); =20 + /* KASAN is now initialized, enable it. */ + static_branch_enable(&kasan_flag_enabled); + /* At this point kasan is fully initialized. Enable error messages */ init_task.kasan_depth =3D 0; pr_info("KernelAddressSanitizer initialized.\n"); diff --git a/arch/powerpc/mm/kasan/init_32.c b/arch/powerpc/mm/kasan/init_3= 2.c index 03666d790a53..b0c465f3fbf5 100644 --- a/arch/powerpc/mm/kasan/init_32.c +++ b/arch/powerpc/mm/kasan/init_32.c @@ -141,6 +141,9 @@ void __init kasan_init(void) u64 i; int ret; =20 + if (kasan_arg_disabled) + return; + for_each_mem_range(i, &base, &end) { phys_addr_t top =3D min(end, total_lowmem); =20 @@ -163,6 +166,9 @@ void __init kasan_init(void) =20 clear_page(kasan_early_shadow_page); =20 + /* KASAN is now initialized, enable it. */ + static_branch_enable(&kasan_flag_enabled); + /* At this point kasan is fully initialized. Enable error messages */ init_task.kasan_depth =3D 0; pr_info("KASAN init done\n"); @@ -170,7 +176,7 @@ void __init kasan_init(void) =20 void __init kasan_late_init(void) { - if (IS_ENABLED(CONFIG_KASAN_VMALLOC)) + if (IS_ENABLED(CONFIG_KASAN_VMALLOC) && kasan_enabled()) kasan_unmap_early_shadow_vmalloc(); } =20 diff --git a/arch/powerpc/mm/kasan/init_book3e_64.c b/arch/powerpc/mm/kasan= /init_book3e_64.c index 60c78aac0f63..1e1c10467a2b 100644 --- a/arch/powerpc/mm/kasan/init_book3e_64.c +++ b/arch/powerpc/mm/kasan/init_book3e_64.c @@ -111,6 +111,9 @@ void __init kasan_init(void) u64 i; pte_t zero_pte =3D pfn_pte(virt_to_pfn(kasan_early_shadow_page), PAGE_KER= NEL_RO); =20 + if (kasan_arg_disabled) + return; + for_each_mem_range(i, &start, &end) kasan_init_phys_region(phys_to_virt(start), phys_to_virt(end)); =20 @@ -125,6 +128,9 @@ void __init kasan_init(void) =20 memset(kasan_early_shadow_page, 0, PAGE_SIZE); =20 + /* KASAN is now initialized, enable it. */ + static_branch_enable(&kasan_flag_enabled); + /* Enable error messages */ init_task.kasan_depth =3D 0; pr_info("KASAN init done\n"); diff --git a/arch/powerpc/mm/kasan/init_book3s_64.c b/arch/powerpc/mm/kasan= /init_book3s_64.c index 7d959544c077..9c5cf2354c8b 100644 --- a/arch/powerpc/mm/kasan/init_book3s_64.c +++ b/arch/powerpc/mm/kasan/init_book3s_64.c @@ -56,6 +56,9 @@ void __init kasan_init(void) u64 i; pte_t zero_pte =3D pfn_pte(virt_to_pfn(kasan_early_shadow_page), PAGE_KER= NEL); =20 + if (kasan_arg_disabled) + return; + if (!early_radix_enabled()) { pr_warn("KASAN not enabled as it requires radix!"); return; @@ -94,6 +97,9 @@ void __init kasan_init(void) =20 static_branch_inc(&powerpc_kasan_enabled_key); =20 + /* KASAN is now initialized, enable it. */ + static_branch_enable(&kasan_flag_enabled); + /* Enable error messages */ init_task.kasan_depth =3D 0; pr_info("KASAN init done\n"); diff --git a/arch/riscv/mm/kasan_init.c b/arch/riscv/mm/kasan_init.c index 41c635d6aca4..ac3ac227c765 100644 --- a/arch/riscv/mm/kasan_init.c +++ b/arch/riscv/mm/kasan_init.c @@ -485,6 +485,9 @@ void __init kasan_init(void) phys_addr_t p_start, p_end; u64 i; =20 + if (kasan_arg_disabled) + return; + create_tmp_mapping(); csr_write(CSR_SATP, PFN_DOWN(__pa(tmp_pg_dir)) | satp_mode); =20 @@ -531,6 +534,9 @@ void __init kasan_init(void) memset(kasan_early_shadow_page, KASAN_SHADOW_INIT, PAGE_SIZE); init_task.kasan_depth =3D 0; =20 + /* KASAN is now initialized, enable it. */ + static_branch_enable(&kasan_flag_enabled); + csr_write(CSR_SATP, PFN_DOWN(__pa(swapper_pg_dir)) | satp_mode); local_flush_tlb_all(); } diff --git a/arch/um/kernel/mem.c b/arch/um/kernel/mem.c index 76bec7de81b5..6961841daa12 100644 --- a/arch/um/kernel/mem.c +++ b/arch/um/kernel/mem.c @@ -26,6 +26,9 @@ int kasan_um_is_ready; void kasan_init(void) { + + if (kasan_arg_disabled) + return; /* * kasan_map_memory will map all of the required address space and * the host machine will allocate physical memory as necessary. @@ -33,6 +36,9 @@ void kasan_init(void) kasan_map_memory((void *)KASAN_SHADOW_START, KASAN_SHADOW_SIZE); init_task.kasan_depth =3D 0; kasan_um_is_ready =3D true; + + /* KASAN is now initialized, enable it. */ + static_branch_enable(&kasan_flag_enabled); } =20 static void (*kasan_init_ptr)(void) diff --git a/arch/x86/mm/kasan_init_64.c b/arch/x86/mm/kasan_init_64.c index 0539efd0d216..d7e8c59da435 100644 --- a/arch/x86/mm/kasan_init_64.c +++ b/arch/x86/mm/kasan_init_64.c @@ -343,6 +343,9 @@ void __init kasan_init(void) unsigned long shadow_cea_begin, shadow_cea_per_cpu_begin, shadow_cea_end; int i; =20 + if (kasan_arg_disabled) + return; + memcpy(early_top_pgt, init_top_pgt, sizeof(early_top_pgt)); =20 /* @@ -450,6 +453,9 @@ void __init kasan_init(void) /* Flush TLBs again to be sure that write protection applied. */ __flush_tlb_all(); =20 + /* KASAN is now initialized, enable it. */ + static_branch_enable(&kasan_flag_enabled); + init_task.kasan_depth =3D 0; pr_info("KernelAddressSanitizer initialized\n"); } diff --git a/arch/xtensa/mm/kasan_init.c b/arch/xtensa/mm/kasan_init.c index f39c4d83173a..4a7b77f47225 100644 --- a/arch/xtensa/mm/kasan_init.c +++ b/arch/xtensa/mm/kasan_init.c @@ -70,6 +70,9 @@ void __init kasan_init(void) { int i; =20 + if (kasan_arg_disabled) + return; + BUILD_BUG_ON(KASAN_SHADOW_OFFSET !=3D KASAN_SHADOW_START - (KASAN_START_VADDR >> KASAN_SHADOW_SCALE_SHIFT)); BUILD_BUG_ON(VMALLOC_START < KASAN_START_VADDR); @@ -92,6 +95,9 @@ void __init kasan_init(void) local_flush_tlb_all(); memset(kasan_early_shadow_page, 0, PAGE_SIZE); =20 + /* KASAN is now initialized, enable it. */ + static_branch_enable(&kasan_flag_enabled); + /* At this point kasan is fully initialized. Enable error messages. */ current->kasan_depth =3D 0; pr_info("KernelAddressSanitizer initialized\n"); diff --git a/mm/kasan/sw_tags.c b/mm/kasan/sw_tags.c index 01f19bc4a326..dd963ba4d143 100644 --- a/mm/kasan/sw_tags.c +++ b/mm/kasan/sw_tags.c @@ -40,11 +40,17 @@ void __init kasan_init_sw_tags(void) { int cpu; =20 + if (kasan_arg_disabled) + return; + for_each_possible_cpu(cpu) per_cpu(prng_state, cpu) =3D (u32)get_cycles(); =20 kasan_init_tags(); =20 + /* KASAN is now initialized, enable it. */ + static_branch_enable(&kasan_flag_enabled); + pr_info("KernelAddressSanitizer initialized (sw-tags, stacktrace=3D%s)\n", str_on_off(kasan_stack_collection_enabled())); } --=20 2.41.0