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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> MIME-Version: 1.0 Content-type: text/plain Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 X-Rspamd-Queue-Id: 6CB33100002 X-Stat-Signature: gqtfrhc7o8g5ucgu1yrzn6k6tewn8gfi X-Rspam-User: X-Rspamd-Server: rspam07 X-HE-Tag: 1754375047-750651 X-HE-Meta: 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 kJGwEove reQ1hEFk1pw/DW9/jN5IVRnYcwes5ljEC6CYBuheV7IGNRjc+JkUyQtklNSY/rb6kbvLBj4naZRlq1OKPDfXxh3tyRma4wiQszhvNHWkWIaXKeoU3QvbnnreY9ZnMi2OaQD9SKbL3S7LSMW1Hw6bgt0+ocZJJOROEJhHMcc9bWFBGsA5WC4E7Mj1A41Ug1p/LisM/sRklXtjtH8seUwxAge0EEe8BP1uZQkyCI6VgfND7kZSR2ppK+QaxsoYjDCXhX4zytk4XO+GWJ+0bxbj3x+665wRdtsYbLOKMQ2mTS5hNiWQVlwTbgEDf/oPHaXqO+6SE4ZnRLsZHDJbBoNLEH6WuLU4F7HF486U3ODFe+2SMk4qtrmdPULLzCshQ2GsNBAoZI13iJJciSETbtpJawxmxpA== 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: 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; + 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(); 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 = 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 *start, unsigned long size) { unsigned long shadow_start, shadow_end; + if (!kasan_enabled()) + return; + if (!is_vmalloc_or_module_addr(start)) return; @@ -397,6 +400,9 @@ void __init kasan_populate_early_vm_area_shadow(void *start, unsigned long size) 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; + 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(); + /* 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 = 0; pr_info("KernelAddressSanitizer initialized.\n"); diff --git a/arch/powerpc/mm/kasan/init_32.c b/arch/powerpc/mm/kasan/init_32.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; + if (kasan_arg_disabled) + return; + for_each_mem_range(i, &base, &end) { phys_addr_t top = min(end, total_lowmem); @@ -163,6 +166,9 @@ void __init kasan_init(void) clear_page(kasan_early_shadow_page); + /* 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 = 0; pr_info("KASAN init done\n"); @@ -170,7 +176,7 @@ void __init kasan_init(void) 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(); } 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 = pfn_pte(virt_to_pfn(kasan_early_shadow_page), PAGE_KERNEL_RO); + if (kasan_arg_disabled) + return; + for_each_mem_range(i, &start, &end) kasan_init_phys_region(phys_to_virt(start), phys_to_virt(end)); @@ -125,6 +128,9 @@ void __init kasan_init(void) memset(kasan_early_shadow_page, 0, PAGE_SIZE); + /* KASAN is now initialized, enable it. */ + static_branch_enable(&kasan_flag_enabled); + /* Enable error messages */ init_task.kasan_depth = 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 = pfn_pte(virt_to_pfn(kasan_early_shadow_page), PAGE_KERNEL); + 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) static_branch_inc(&powerpc_kasan_enabled_key); + /* KASAN is now initialized, enable it. */ + static_branch_enable(&kasan_flag_enabled); + /* Enable error messages */ init_task.kasan_depth = 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; + if (kasan_arg_disabled) + return; + create_tmp_mapping(); csr_write(CSR_SATP, PFN_DOWN(__pa(tmp_pg_dir)) | satp_mode); @@ -531,6 +534,9 @@ void __init kasan_init(void) memset(kasan_early_shadow_page, KASAN_SHADOW_INIT, PAGE_SIZE); init_task.kasan_depth = 0; + /* 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 = 0; kasan_um_is_ready = true; + + /* KASAN is now initialized, enable it. */ + static_branch_enable(&kasan_flag_enabled); } 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; + if (kasan_arg_disabled) + return; + memcpy(early_top_pgt, init_top_pgt, sizeof(early_top_pgt)); /* @@ -450,6 +453,9 @@ void __init kasan_init(void) /* Flush TLBs again to be sure that write protection applied. */ __flush_tlb_all(); + /* KASAN is now initialized, enable it. */ + static_branch_enable(&kasan_flag_enabled); + init_task.kasan_depth = 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; + if (kasan_arg_disabled) + return; + BUILD_BUG_ON(KASAN_SHADOW_OFFSET != 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); + /* 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 = 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; + if (kasan_arg_disabled) + return; + for_each_possible_cpu(cpu) per_cpu(prng_state, cpu) = (u32)get_cycles(); kasan_init_tags(); + /* KASAN is now initialized, enable it. */ + static_branch_enable(&kasan_flag_enabled); + pr_info("KernelAddressSanitizer initialized (sw-tags, stacktrace=%s)\n", str_on_off(kasan_stack_collection_enabled())); } -- 2.41.0