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Tue, 17 Mar 2026 02:39:42 +0000 (GMT) Message-ID: <161b024f-9022-45c6-9808-815b8ea83bd9@linux.ibm.com> Date: Tue, 17 Mar 2026 08:09:41 +0530 Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 09/15] arch/powerpc: don't initialize kasan if it's disabled To: "Christophe Leroy (CS GROUP)" , Baoquan He , kasan-dev@googlegroups.com Cc: 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 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> Content-Language: en-US From: Sourabh Jain In-Reply-To: <0bc30137-3f1d-4a4a-8573-8f26866fcc26@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Authority-Analysis: v=2.4 cv=MMttWcZl c=1 sm=1 tr=0 ts=69b8bef6 cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=IkcTkHD0fZMA:10 a=Yq5XynenixoA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=uAbxVGIbfxUO_5tXvNgY:22 a=20KFwNOVAAAA:8 a=voM4FWlXAAAA:8 a=VnNF1IyMAAAA:8 a=5rPG81X-PvUkzTHTjkcA:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 a=IC2XNlieTeVoXbcui8wp:22 X-Proofpoint-ORIG-GUID: HWoExDelsoEK2cbRMVIpcCVRBxC05kk2 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMzE3MDAxNyBTYWx0ZWRfXywbZf72OQQWO 6dqxsntbcC6njezyY+HUqTo0rMFEcHOa573IhojGtmtl6Ek/h9rDkQ2yRH41g07ro4PtNLNlOC6 bI4CP+Eo7cJqO30z4F4OpwJRb7oS9s2B+PdrBZGIhhBwTfWdoX+mdVUGUIDK9tPDGQazj/yuJTA 8yPRocQXGhSyuDnhQ4sEbwI/SIqoTBAF+OwumN6W7cofg79urUof1tkhBjgR3ss/tzvou0Gkwsd kjOMcJu1j/1arCqKQXLU99t6T+WhXTTVqGlTTLue2d9D5oEUDDDzvtgbq8qOG3+dpMjYEFX37y/ MF9157RX5GHtISXonVIOAQoXt0lzPq516Jmwt2G/r+aSNaAAKuzXUoWGFtTXrZT8xJszLvgcI2P Fo9Fl3eSCV46HHhRmWODojBiOnxk4jwwWvyrUxIBwQYEXgzcNqAiNbnyKMgsdgR+EmKOgA328e5 Ky+m+8qMEGSY1KVS2Cw== X-Proofpoint-GUID: ey18HYg4huOLB-DOzeSP3hWnR40_py-b X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-03-16_06,2026-03-16_06,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 lowpriorityscore=0 malwarescore=0 spamscore=0 priorityscore=1501 impostorscore=0 adultscore=0 phishscore=0 clxscore=1015 bulkscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2603050001 definitions=main-2603170017 On 12/03/26 16:53, 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 ? Yes this should work. Thanks. - Sourabh Jain > >> >> $ 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 >> >> - Sourabh Jain >> >