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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> 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: nw5tGDeHuP58NYdx7rIyD_waSaOS2MN340KM-P-kYD4_1773713443 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Queue-Id: D92A01C0002 X-Rspamd-Server: rspam08 X-Stat-Signature: z31ajatao4fhpz8efnykuzarbxbh1ahk X-HE-Tag: 1773713450-727463 X-HE-Meta: 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 Zeri/HCE 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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.