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 EE0A8158A1F for ; Tue, 15 Oct 2024 01:59:20 +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=1728957562; cv=none; b=KD01bXrHghjtRBMXSYUY9flPUBh43M8joVKICjh7S78GQ206yLDZnToAAEd1vmFW6UIGsEE7XjTrbodxmC3c6tcfRV/d86lFui6PaCMT+M3mf0E4FNiP0nOUAlMXpW20h9cWKqkI75xxngnqPGghd7Qo59jZm2LuGh1QiQGRdhc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728957562; c=relaxed/simple; bh=/mpWQQUg4SLGbw0b6uVKlir/V5LQ1XvyAyhlgfEndo8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=rhYWJVJ/+GrpBhr9kzj9pG/otEI6w+FxZAM7R+ic1vVlNGmeXJ/q+FgtVLIJxC3fFDhafcBq+VcqESbyv1wJ2vuSldighirLJQWMIYMgE17GDKbH8qbYIxw1Ip5qsMhe/+xGARKONIE1FT0Fa4wUDrFhtRgycEZNkxb54z/YvXM= 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=PO6QRUSi; 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="PO6QRUSi" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1728957560; 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=ml1ZBBcs96kgD+D7cgCrxHrlfi6RlfUgZkDg/aeocjg=; b=PO6QRUSicuQZJI8spfEgOLvz+G9kiSqXYEeGkatBFQJzmWdiHW1Me7gLI07My4NLEXwZ4J gupc2flpLmtaxPc73O2vjb/7Q0FP0UF7PyPbWHhn+Q3IF8svYc0tKLbfT/PJ2gIgnxqWag eENUR4uMDRc73VJpqnwASEsFVK9FnXI= Received: from mx-prod-mc-01.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-370-m3OzuSbkP1ilKYyrQmSsqg-1; Mon, 14 Oct 2024 21:59:16 -0400 X-MC-Unique: m3OzuSbkP1ilKYyrQmSsqg-1 Received: from mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.40]) (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-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 74E88195608B; Tue, 15 Oct 2024 01:59:14 +0000 (UTC) Received: from fedora (unknown [10.72.116.119]) by mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id E666419560AA; Tue, 15 Oct 2024 01:59:07 +0000 (UTC) Date: Tue, 15 Oct 2024 09:59:02 +0800 From: Ming Lei To: Robin Murphy Cc: Christoph Hellwig , Hannes Reinecke , Hamza Mahfooz , Dan Williams , linux-block@vger.kernel.org, io-uring@vger.kernel.org, linux-raid@vger.kernel.org, iommu@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [Report] annoyed dma debug warning "cacheline tracking EEXIST, overlapping mappings aren't supported" Message-ID: References: <426b5600-7489-43a7-8007-ac4d9dbc9aca@suse.de> <20241014074151.GA22419@lst.de> <7411ae1d-5e36-46da-99cf-c485ebdb31bc@arm.com> Precedence: bulk X-Mailing-List: linux-raid@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: <7411ae1d-5e36-46da-99cf-c485ebdb31bc@arm.com> X-Scanned-By: MIMEDefang 3.0 on 10.30.177.40 On Mon, Oct 14, 2024 at 07:09:08PM +0100, Robin Murphy wrote: > On 14/10/2024 8:58 am, Ming Lei wrote: > > On Mon, Oct 14, 2024 at 09:41:51AM +0200, Christoph Hellwig wrote: > > > On Mon, Oct 14, 2024 at 09:23:14AM +0200, Hannes Reinecke wrote: > > > > > 3) some storage utilities > > > > > - dm thin provisioning utility of thin_check > > > > > - `dt`(https://github.com/RobinTMiller/dt) > > > > > > > > > > I looks like same user buffer is used in more than 1 dio. > > > > > > > > > > 4) some self cooked test code which does same thing with 1) > > > > > > > > > > In storage stack, the buffer provider is far away from the actual DMA > > > > > controller operating code, which doesn't have the knowledge if > > > > > DMA_ATTR_SKIP_CPU_SYNC should be set. > > > > > > > > > > And suggestions for avoiding this noise? > > > > > > > > > Can you check if this is the NULL page? Operations like 'discard' will > > > > create bios with several bvecs all pointing to the same NULL page. > > > > That would be the most obvious culprit. > > > > > > The only case I fully understand without looking into the details > > > is raid1, and that will obviously map the same data multiple times > > > > The other cases should be concurrent DIOs on same userspace buffer. > > active_cacheline_insert() does already bail out for DMA_TO_DEVICE, so it > returning -EEXIST to tickle the warning would seem to genuinely imply these > are DMA mappings requesting to *write* the same cacheline concurrently, > which is indeed broken in general. The two io_uring tests are READ, and the dm thin_check are READ too. For the raid1 case, the warning is from raid1_sync_request() which may have both READ/WRITE IO. Thanks, Ming