From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 EB4FE46B8 for ; Tue, 15 Oct 2024 03:47:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728964042; cv=none; b=SCLZqMP5R4auCskJLZZhXGiKgl7o/Bq7SLA2Tuw7lXv1YResNd7gkI+6UI3FSMYd9OxAwWa7ADp97wXEOwylyIGI+z1qcO53/iutCTzleKxRJQYbONdY5C4CL+kY4feh06B6H3LluO8o7gcJ9Up6QLBJuhHaRDUdhgo472tKdMc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728964042; c=relaxed/simple; bh=+BcVhtftxxjodquIf2K4pPv71t8bgmiSroFSbaGWemA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=CKvUGey2gOeAp+RRk92BiRle9uaGY7Q1WwvXT7F9JbVCTP7TAg4HeQnGoxK4+X1bE3Fg7zKBh+vzCw/TYufYJkzOLD8lqvIBBQAj3KXjtz1e8XU3g9Jtpo3k0nPVqJSvr6w/9qDysXnvrB/dk5XKLkbBy40kgWL3J6JiUPDuTlo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none 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=STXzvCup; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none 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="STXzvCup" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1728964038; 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: in-reply-to:in-reply-to:references:references; bh=8dfHwMGJbsawxs7janPhhHUV4M9LSvsDgTpkLW3bePY=; b=STXzvCuplPTx7Dj8sWrev8owqY19SnyibVINJs8uHkuZU6qJo5j+nIU2mDhG+zQaP7ys3Z bfYF18LM6c0BoCRyrWR9vDwF9bp+HvJAVbkBnr78wI4j4Nn32AIcqbYTNouUTmH8zB4f8C jcGmPlJvPm+QlP3JUCzAlPRYVLxnpR0= 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-544-P6e0lCY_PJuFC2ui5jvLjg-1; Mon, 14 Oct 2024 23:47:15 -0400 X-MC-Unique: P6e0lCY_PJuFC2ui5jvLjg-1 Received: from mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.15]) (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 CC24A1956083; Tue, 15 Oct 2024 03:47:11 +0000 (UTC) Received: from localhost (unknown [10.72.112.16]) by mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 5FA781956089; Tue, 15 Oct 2024 03:47:08 +0000 (UTC) Date: Tue, 15 Oct 2024 11:47:04 +0800 From: Baoquan He To: Ryan Roberts Cc: Andrew Morton , Anshuman Khandual , Ard Biesheuvel , Catalin Marinas , David Hildenbrand , Greg Marsden , Ivan Ivanov , Kalesh Singh , Marc Zyngier , Mark Rutland , Matthias Brugger , Miroslav Benes , Will Deacon , kexec@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [RFC PATCH v1 19/57] crash: Remove PAGE_SIZE compile-time constant assumption Message-ID: References: <20241014105514.3206191-1-ryan.roberts@arm.com> <20241014105912.3207374-1-ryan.roberts@arm.com> <20241014105912.3207374-19-ryan.roberts@arm.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=us-ascii Content-Disposition: inline In-Reply-To: <20241014105912.3207374-19-ryan.roberts@arm.com> X-Scanned-By: MIMEDefang 3.0 on 10.30.177.15 On 10/14/24 at 11:58am, Ryan Roberts wrote: > To prepare for supporting boot-time page size selection, refactor code > to remove assumptions about PAGE_SIZE being compile-time constant. Code > intended to be equivalent when compile-time page size is active. > > Updated BUILD_BUG_ON() to test against limit. > > Signed-off-by: Ryan Roberts > --- > > ***NOTE*** > Any confused maintainers may want to read the cover note here for context: > https://lore.kernel.org/all/20241014105514.3206191-1-ryan.roberts@arm.com/ > > kernel/crash_core.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/crash_core.c b/kernel/crash_core.c > index 63cf89393c6eb..978c600a47ac8 100644 > --- a/kernel/crash_core.c > +++ b/kernel/crash_core.c > @@ -465,7 +465,7 @@ static int __init crash_notes_memory_init(void) > * Break compile if size is bigger than PAGE_SIZE since crash_notes > * definitely will be in 2 pages with that. > */ > - BUILD_BUG_ON(size > PAGE_SIZE); > + BUILD_BUG_ON(size > PAGE_SIZE_MIN); This should be OK. While one thing which could happen is if selected size is 64K, PAGE_SIZE_MIN is 4K, it will issue a false-positive warning when compiling while actual it's not a problem during running. Not sure if that could happen on arm64. Anyway, we can check the crash_notes to get why it's so big when it really happens. So, Acked-by: Baoquan He > > crash_notes = __alloc_percpu(size, align); > if (!crash_notes) { > -- > 2.43.0 > >