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Tue, 12 Aug 2025 15:10:09 +0000 (UTC) Date: Tue, 12 Aug 2025 23:10:04 +0800 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, sj@kernel.org, lorenzo.stoakes@oracle.com, elver@google.com, snovitoll@gmail.com Subject: Re: [PATCH v2 00/12] mm/kasan: make kasan=on|off work for all three modes Message-ID: References: <20250812124941.69508-1-bhe@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250812124941.69508-1-bhe@redhat.com> X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 X-Stat-Signature: rxegibb46477kkdad9beanhwqswtwhdx X-Rspam-User: X-Rspamd-Queue-Id: D530E80009 X-Rspamd-Server: rspam02 X-HE-Tag: 1755011427-459151 X-HE-Meta: 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 XziYiKb/ Z+JRw01SYTYJr3vdjqyRhEtSIVBth1UtWTIQarCl8AzP5V9M2/R0EhyQwC2ykAUJ32CEdEISm0CpFzo2ZL6f8NRDwRueHxRWnl8x94eqCtNjAsAQSEnYMBVF8h361ORPUOOMYhQEyj40sWywQf3gBmc8mGmX+7Jk9OhyoLNj0hAlV2O7d1pvK5HYgyg== 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: On 08/12/25 at 08:49pm, Baoquan He wrote: > Currently only hw_tags mode of kasan can be enabled or disabled with > kernel parameter kasan=on|off for built kernel. For kasan generic and > sw_tags mode, there's no way to disable them once kernel is built. > This is not convenient sometime, e.g in system kdump is configured. > When the 1st kernel has KASAN enabled and crash triggered to switch to > kdump kernel, the generic or sw_tags mode will cost much extra memory > for kasan shadow while in fact it's meaningless to have kasan in kdump > kernel. > > So this patchset moves the kasan=on|off out of hw_tags scope and into > common code to make it visible in generic and sw_tags mode too. Then we > can add kasan=off in kdump kernel to reduce the unneeded meomry cost for > kasan. > > Changelog: > ==== > v1->v2: > - Add __ro_after_init for __ro_after_init, and remove redundant blank ~~~~~~~~~~~~~ s/__ro_after_init/kasan_arg_disabled/ Sorry for typo here. > lines in mm/kasan/common.c. Thanks to Marco.