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From: Christoph Hellwig <hch@lst.de>
To: Ioana Ciornei <ioana.ciornei@nxp.com>
Cc: Jeremy Linton <jeremy.linton@arm.com>,
	Hamza Mahfooz <someguy@effective-light.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Christoph Hellwig <hch@lst.de>,
	Marek Szyprowski <m.szyprowski@samsung.com>,
	Robin Murphy <robin.murphy@arm.com>,
	"iommu@lists.linux-foundation.org"
	<iommu@lists.linux-foundation.org>,
	Dan Williams <dan.j.williams@intel.com>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>
Subject: Re: DPAA2 triggers, [PATCH] dma debug: report -EEXIST errors in add_dma_entry
Date: Fri, 1 Oct 2021 06:19:59 +0200	[thread overview]
Message-ID: <20211001041959.GA17448@lst.de> (raw)
In-Reply-To: <20210914154504.z6vqxuh3byqwgfzx@skbuf>

On Tue, Sep 14, 2021 at 03:45:06PM +0000, Ioana Ciornei wrote:
> [  245.927020] fsl_dpaa2_eth dpni.3: scather-gather idx 0 P=20a7320000 N=20a7320 D=20a7320000 L=30 DMA_BIDIRECTIONAL dma map error check not applicable·
> [  245.927048] fsl_dpaa2_eth dpni.3: scather-gather idx 1 P=20a7320030 N=20a7320 D=20a7320030 L=5a8 DMA_BIDIRECTIONAL dma map error check not applicable
> [  245.927062] DMA-API: cacheline tracking EEXIST, overlapping mappings aren't supported
> 
> The first line is the dump of the dma_debug_entry which is already present
> in the radix tree and the second one is the entry which just triggered
> the EEXIST.
> 
> As we can see, they are not actually overlapping, at least from my
> understanding. The first one starts at 0x20a7320000 with a size 0x30
> and the second one at 0x20a7320030.

They overlap the cache lines.  Which means if you use this driver
on a system that is not dma coherent you will corrupt data.

  parent reply	other threads:[~2021-10-01  4:20 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-18 12:54 Hamza Mahfooz
2021-06-22  7:41 ` Christoph Hellwig
2021-09-09  3:33 ` DPAA2 triggers, " Jeremy Linton
2021-09-09 21:16   ` Ioana Ciornei
2021-09-10 10:23   ` Christoph Hellwig
2021-09-14 15:45   ` Ioana Ciornei
2021-09-30 13:37     ` Karsten Graul
2021-10-01 12:52       ` Gerald Schaefer
2021-10-06 13:10         ` Gerald Schaefer
2021-10-06 13:21           ` Gerald Schaefer
2021-10-06 14:23           ` Robin Murphy
2021-10-06 15:06             ` Gerald Schaefer
2021-10-07 10:59             ` Karsten Graul
2021-10-07 16:40               ` Gerald Schaefer
2021-10-11 11:47               ` Christoph Hellwig
2021-10-01  4:19     ` Christoph Hellwig [this message]
2021-10-01  9:21       ` Ioana Ciornei

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