From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 26298225788 for ; Tue, 9 Dec 2025 03:28:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765250889; cv=none; b=PDOeZ2zQONjAuRaStPvZFTWkj/Jw2PqZOWjEwQ0fwHIwL7EJzdFtmoqaL+G2qta8egl3Ze1ePLQ8r9yEvdnMdjoqQsXf0Dx+TuFCALa7rdi4qZeOkAoxdqXfw7KJHlrWrAhcSK7o69dt3BxvZJsSI4ZWufciOrcFyMqgiyzQ2I0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765250889; c=relaxed/simple; bh=TV395wru/MjmBXHF/N/tr+oG8PuO69xkXTUncFbs1IY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Z1C1qpTmhsPXrj0LKFeSRLrmJbM93wsUTdDrdUfU4XtE7l+HYYxFk9nv1Peo6oSRScvow4I3qQ+E0Nq7HR8hE/9JsOhDvxf+jXQym0haKlV9Vwb50/RpS7L+n+WElQS90UDwbf2dFakIdgET7dL4IVwxTm8k+3ZRW01NXxuQ2es= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=Fm1AsM8E; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Fm1AsM8E" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1765250884; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=NbFVdOXb1Nr6+8TD5KZltub496iqTHAYaOUL7OnbUgQ=; b=Fm1AsM8E0LfOVVgw1LTPD3/6LQj5SrgYqPGEjwEJowAxPRFr883VZHuJF5Wsc/pKAEilqi HComPFYkC6BJlLN3SXIwHQSdPcalMN3TJYAfwHAw1Suh/DAIbrxH9XyiaGe28eSaao1Mp0 2CpAbL71kuSqTVFWmpxtJreQAT/GQXQ= Received: from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-251-P4iN0WunM0CoN3RLOuYODw-1; Mon, 08 Dec 2025 22:28:00 -0500 X-MC-Unique: P4iN0WunM0CoN3RLOuYODw-1 X-Mimecast-MFC-AGG-ID: P4iN0WunM0CoN3RLOuYODw_1765250878 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (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-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id A24091956088; Tue, 9 Dec 2025 03:27:57 +0000 (UTC) Received: from localhost (unknown [10.72.112.51]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 2678719560AD; Tue, 9 Dec 2025 03:27:54 +0000 (UTC) Date: Tue, 9 Dec 2025 11:27:50 +0800 From: Baoquan He To: Andrey Konovalov Cc: linux-mm@kvack.org, ryabinin.a.a@gmail.com, glider@google.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, elver@google.com, sj@kernel.org, lorenzo.stoakes@oracle.com, snovitoll@gmail.com, christophe.leroy@csgroup.eu Subject: Re: [PATCH v4 02/12] mm/kasan: move kasan= code to common place Message-ID: References: <20251128033320.1349620-1-bhe@redhat.com> <20251128033320.1349620-3-bhe@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 On 12/04/25 at 05:39pm, Andrey Konovalov wrote: > On Fri, Nov 28, 2025 at 4:33 AM Baoquan He wrote: > > > > This allows generic and sw_tags to be set in kernel cmdline too. > > > > When at it, rename 'kasan_arg' to 'kasan_arg_disabled' as a bool > > variable. And expose 'kasan_flag_enabled' to kasan common place > > too. > > This asks to be two separate patches. Makes sense to me, thanks.. > > > > > This is prepared for later adding kernel parameter kasan=on|off for > > all three kasan modes. > > > > Signed-off-by: Baoquan He > > --- > > include/linux/kasan-enabled.h | 4 +++- > > mm/kasan/common.c | 20 ++++++++++++++++++-- > > mm/kasan/hw_tags.c | 28 ++-------------------------- > > 3 files changed, 23 insertions(+), 29 deletions(-) > > > > diff --git a/include/linux/kasan-enabled.h b/include/linux/kasan-enabled.h > > index 9eca967d8526..b05ec6329fbe 100644 > > --- a/include/linux/kasan-enabled.h > > +++ b/include/linux/kasan-enabled.h > > @@ -4,13 +4,15 @@ > > > > #include > > > > -#if defined(CONFIG_ARCH_DEFER_KASAN) || defined(CONFIG_KASAN_HW_TAGS) > > These changes of moving/removing CONFIG_ARCH_DEFER_KASAN also seem to > belong to a separate patch (or should be combined with patch 12?); the > commit message does not even mention them. Yes, combining tit with patch 12 sounds great. I will move patch 12 to earlier oder. > > > +extern bool kasan_arg_disabled; > > + > > /* > > * Global runtime flag for KASAN modes that need runtime control. > > * Used by ARCH_DEFER_KASAN architectures and HW_TAGS mode. > > */ > > DECLARE_STATIC_KEY_FALSE(kasan_flag_enabled); > > So kasan_flag_enabled is now always exposed here... > > > > > +#if defined(CONFIG_ARCH_DEFER_KASAN) || defined(CONFIG_KASAN_HW_TAGS) > > but the functions that use it are not. Why? Good question. I didn't consider this reasonably. At the beginning, I thought it could cause problem if people has specified 'kasan=off' before patch 12 when bisecting. That's why put kasan_arg_disabled and kasan_flag_enabled declaration outside of any ifdeffery scope. Now after reconsiderring, putting patch 12 earlier can solve the problem. Thanks for careful reivewing, all suggestions are good and taken. > > > > /* > > * Runtime control for shadow memory initialization or HW_TAGS mode. > > * Uses static key for architectures that need deferred KASAN or HW_TAGS. > > diff --git a/mm/kasan/common.c b/mm/kasan/common.c > > index 1d27f1bd260b..ac14956986ee 100644 > > --- a/mm/kasan/common.c > > +++ b/mm/kasan/common.c > > @@ -32,14 +32,30 @@ > > #include "kasan.h" > > #include "../slab.h" > > > > -#if defined(CONFIG_ARCH_DEFER_KASAN) || defined(CONFIG_KASAN_HW_TAGS) > > /* > > * Definition of the unified static key declared in kasan-enabled.h. > > * This provides consistent runtime enable/disable across KASAN modes. > > */ > > DEFINE_STATIC_KEY_FALSE(kasan_flag_enabled); > > EXPORT_SYMBOL_GPL(kasan_flag_enabled); > > -#endif > > + > > +bool kasan_arg_disabled __ro_after_init; > > +/* kasan=off/on */ > > +static int __init early_kasan_flag(char *arg) > > +{ > > + if (!arg) > > + return -EINVAL; > > + > > + if (!strcmp(arg, "off")) > > + kasan_arg_disabled = true; > > + else if (!strcmp(arg, "on")) > > + kasan_arg_disabled = false; > > + else > > + return -EINVAL; > > + > > + return 0; > > +} > > +early_param("kasan", early_kasan_flag); > > > > struct slab *kasan_addr_to_slab(const void *addr) > > { > > diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c > > index 1c373cc4b3fa..709c91abc1b1 100644 > > --- a/mm/kasan/hw_tags.c > > +++ b/mm/kasan/hw_tags.c > > @@ -22,12 +22,6 @@ > > > > #include "kasan.h" > > > > -enum kasan_arg { > > - KASAN_ARG_DEFAULT, > > - KASAN_ARG_OFF, > > - KASAN_ARG_ON, > > -}; > > - > > enum kasan_arg_mode { > > KASAN_ARG_MODE_DEFAULT, > > KASAN_ARG_MODE_SYNC, > > @@ -41,7 +35,6 @@ enum kasan_arg_vmalloc { > > KASAN_ARG_VMALLOC_ON, > > }; > > > > -static enum kasan_arg kasan_arg __ro_after_init; > > static enum kasan_arg_mode kasan_arg_mode __ro_after_init; > > static enum kasan_arg_vmalloc kasan_arg_vmalloc __initdata; > > > > @@ -81,23 +74,6 @@ unsigned int kasan_page_alloc_sample_order = PAGE_ALLOC_SAMPLE_ORDER_DEFAULT; > > > > DEFINE_PER_CPU(long, kasan_page_alloc_skip); > > > > -/* kasan=off/on */ > > -static int __init early_kasan_flag(char *arg) > > -{ > > - if (!arg) > > - return -EINVAL; > > - > > - if (!strcmp(arg, "off")) > > - kasan_arg = KASAN_ARG_OFF; > > - else if (!strcmp(arg, "on")) > > - kasan_arg = KASAN_ARG_ON; > > - else > > - return -EINVAL; > > - > > - return 0; > > -} > > -early_param("kasan", early_kasan_flag); > > - > > /* kasan.mode=sync/async/asymm */ > > static int __init early_kasan_mode(char *arg) > > { > > @@ -222,7 +198,7 @@ void kasan_init_hw_tags_cpu(void) > > * When this function is called, kasan_flag_enabled is not yet > > * set by kasan_init_hw_tags(). Thus, check kasan_arg instead. > > */ > > - if (kasan_arg == KASAN_ARG_OFF) > > + if (kasan_arg_disabled) > > return; > > > > /* > > @@ -240,7 +216,7 @@ void __init kasan_init_hw_tags(void) > > return; > > > > /* If KASAN is disabled via command line, don't initialize it. */ > > - if (kasan_arg == KASAN_ARG_OFF) > > + if (kasan_arg_disabled) > > return; > > > > switch (kasan_arg_mode) { > > -- > > 2.41.0 > > >