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Mon, 16 Mar 2026 22:10:46 -0400 X-MC-Unique: 3Bd5hukVNg6_8EEIPcheoQ-1 X-Mimecast-MFC-AGG-ID: 3Bd5hukVNg6_8EEIPcheoQ_1773713443 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 AF4D218005B6; Tue, 17 Mar 2026 02:10:41 +0000 (UTC) Received: from localhost (unknown [10.72.112.155]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id B823C1955F19; Tue, 17 Mar 2026 02:10:38 +0000 (UTC) Date: Tue, 17 Mar 2026 10:10:34 +0800 From: Baoquan He To: Sourabh Jain , "Christophe Leroy (CS GROUP)" Cc: kasan-dev@googlegroups.com, linux-mm@kvack.org, andreyknvl@gmail.com, ryabinin.a.a@gmail.com, glider@google.com, dvyukov@google.com, linux-kernel@vger.kernel.org, linux-um@lists.infradead.org, linux-arm-kernel@lists.infradead.org, loongarch@lists.linux.dev, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, x86@kernel.org, chris@zankel.net, jcmvbkbc@gmail.com, linux-s390@vger.kernel.org, hca@linux.ibm.com Subject: Re: [PATCH v5 09/15] arch/powerpc: don't initialize kasan if it's disabled Message-ID: References: <20260225081412.76502-1-bhe@redhat.com> <20260225081412.76502-10-bhe@redhat.com> <71921cca-b890-41c4-93e9-957d3f647ffa@linux.ibm.com> <0bc30137-3f1d-4a4a-8573-8f26866fcc26@kernel.org> X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 In-Reply-To: <0bc30137-3f1d-4a4a-8573-8f26866fcc26@kernel.org> X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 X-Mimecast-MFC-PROC-ID: MEZ2JDP5y5vum4C4bFgplwwSfQaUALieYwGBl43oVcQ_1773713443 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit On 03/12/26 at 12:23pm, Christophe Leroy (CS GROUP) wrote: > > > Le 12/03/2026 à 12:12, Sourabh Jain a écrit : > > > > > > On 25/02/26 13:44, Baoquan He wrote: > > > Here, kasan is disabled if specified 'kasan=off' in kernel cmdline. > > > > > > This includes 32bit, book3s/64 and book3e/64. > > > > > > Signed-off-by: Baoquan He > > > Cc: linuxppc-dev@lists.ozlabs.org > > > --- > > >   arch/powerpc/mm/kasan/init_32.c        | 6 +++++- > > >   arch/powerpc/mm/kasan/init_book3e_64.c | 4 ++++ > > >   arch/powerpc/mm/kasan/init_book3s_64.c | 4 ++++ > > >   3 files changed, 13 insertions(+), 1 deletion(-) > > > > > > diff --git a/arch/powerpc/mm/kasan/init_32.c > > > b/arch/powerpc/mm/kasan/ init_32.c > > > index 1d083597464f..0ea2a636c992 100644 > > > --- a/arch/powerpc/mm/kasan/init_32.c > > > +++ b/arch/powerpc/mm/kasan/init_32.c > > > @@ -141,6 +141,10 @@ void __init kasan_init(void) > > >       u64 i; > > >       int ret; > > > +    /* If KASAN is disabled via command line, don't initialize it. */ > > > +    if (kasan_arg_disabled) > > > +        return; > > > + > > >       for_each_mem_range(i, &base, &end) { > > >           phys_addr_t top = min(end, total_lowmem); > > > @@ -170,7 +174,7 @@ 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 0d3a73d6d4b0..fbe4c9a7e460 100644 > > > --- a/arch/powerpc/mm/kasan/init_book3e_64.c > > > +++ b/arch/powerpc/mm/kasan/init_book3e_64.c > > > @@ -111,6 +111,10 @@ 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 is disabled via command line, don't initialize it. */ > > > +    if (kasan_arg_disabled) > > > +        return; > > > + > > >       for_each_mem_range(i, &start, &end) > > >           kasan_init_phys_region(phys_to_virt(start), phys_to_virt(end)); > > > diff --git a/arch/powerpc/mm/kasan/init_book3s_64.c > > > b/arch/powerpc/mm/ kasan/init_book3s_64.c > > > index dcafa641804c..f7906f9ef9be 100644 > > > --- a/arch/powerpc/mm/kasan/init_book3s_64.c > > > +++ b/arch/powerpc/mm/kasan/init_book3s_64.c > > > @@ -54,6 +54,10 @@ void __init kasan_init(void) > > >       u64 i; > > >       pte_t zero_pte = pfn_pte(virt_to_pfn(kasan_early_shadow_page), > > > PAGE_KERNEL); > > > +    /* If KASAN is disabled via command line, don't initialize it. */ > > > +    if (kasan_arg_disabled) > > > +        return; > > > + > > >       if (!early_radix_enabled()) { > > >           pr_warn("KASAN not enabled as it requires radix!"); > > >           return; > > > > Should we log in the kernel log buffer that KASAN is disabled? > > > > Right now, I don't see the kernel advertising the same. > > When KASAN is enabled it is advertised with: > > pr_info("KernelAddressSanitizer initialized (generic)\n"); > > Isn't the absence of that message enough to understand KASAN is not there ? Right, that's the way I took when I tested it. > > > > > $ dmesg | grep -i kasan > > [    0.000000] Kernel command line: BOOT_IMAGE=(ieee1275//vdevice/v- > > scsi@30000070/disk@8100000000000000,msdos2)/vmlinuz-7.0.0-rc3+ > > crashkernel=2G kasan=off > > > > Tested this series on powerpc Pseries platform. > > So feel free to add: > > Tested-by: Sourabh Jain Thanks for testing.