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Date:   Thu, 20 Aug 2020 17:49:41 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Nicolin Chen <nicoleotsuka@gmail.com>
Cc:     Stephen Rothwell <sfr@canb.auug.org.au>,
        Christoph Hellwig <hch@lst.de>,
        Linux Next Mailing List <linux-next@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: linux-next: boot failure after merge of the dma-mapping tree
Message-ID: <20200820154941.GA11349@lst.de>
References: <20200820155112.29459f41@canb.auug.org.au> <20200820083617.GA6124@Asurada>
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On Thu, Aug 20, 2020 at 01:36:17AM -0700, Nicolin Chen wrote:
> Took a quick look -- the boundary_size is seemingly passed from
> https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/arch/powerpc/kernel/iommu.c#n240
> 
> 	boundary_size = ALIGN(dma_get_seg_boundary(dev) + 1,
> 			1 << tbl->it_page_shift);
> 
> Looks like an overflow happens due to (ULONG_MAX + 1). Should
> we fix here instead (or also)?

Yes, please.  I'll drop the patch again for now, but once we've
got this sorted out I'll readd it.