From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: zalon scsi WARNINGs at kernel/dma/mapping.c:290 dma_free_attrs+0x5c/0x84 Date: Tue, 19 Feb 2019 16:16:09 +0100 Message-ID: <20190219151609.GA4121@lst.de> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Meelis Roos Cc: iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, Christoph Hellwig , linux-parisc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: iommu@lists.linux-foundation.org On Tue, Feb 19, 2019 at 12:57:18AM +0200, Meelis Roos wrote: > I tried latest Linux on HP A180C (32-bit pa-risc). It works but the Zalon SCSI driver barfs warnings for GSC addon differential scsi board. > > The warnings seem to be DMA API related. Packaged 4.19 and self-compiled 5.0.0-rc7 exhibit the same problem. It looks like the driver is trying to free DMA coherent memory with irqs disabled, which is a big no-go on most non-coherent architectures (which includes parisc). The DMA coherent code in this driver is pretty convoluted, but I'll see what I can do. The warning has been there for a couple kernel release, and the issue basically goes back to day 0 of support for non-coherent architectures.