From: Robin Murphy <robin.murphy@arm.com>
To: Will Deacon <will@kernel.org>
Cc: Claire Chang <tientzu@chromium.org>,
Christoph Hellwig <hch@lst.de>,
Qian Cai <quic_qiancai@quicinc.com>,
Rob Herring <robh+dt@kernel.org>,
mpe@ellerman.id.au, Joerg Roedel <joro@8bytes.org>,
Frank Rowand <frowand.list@gmail.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
boris.ostrovsky@oracle.com, jgross@suse.com,
Marek Szyprowski <m.szyprowski@samsung.com>,
heikki.krogerus@linux.intel.com,
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dri-devel@lists.freedesktop.org, chris@chris-wilson.co.uk,
grant.likely@arm.com, paulus@samba.org, mingo@kernel.org,
Jianxiong Gao <jxgao@google.com>,
Stefano Stabellini <sstabellini@kernel.org>,
Saravana Kannan <saravanak@google.com>,
xypron.glpk@gmx.de,
"Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
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Nicolas Boichat <drinkcat@chromium.org>,
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Subject: Re: [PATCH v14 06/12] swiotlb: Use is_swiotlb_force_bounce for swiotlb data bouncing
Date: Thu, 24 Jun 2021 12:34:09 +0100 [thread overview]
Message-ID: <452155d2-c98e-23f6-86d6-3a2ff2e74783@arm.com> (raw)
In-Reply-To: <20210624111855.GA1382@willie-the-truck>
On 2021-06-24 12:18, Will Deacon wrote:
> On Thu, Jun 24, 2021 at 12:14:39PM +0100, Robin Murphy wrote:
>> On 2021-06-24 07:05, Claire Chang wrote:
>>> On Thu, Jun 24, 2021 at 1:43 PM Christoph Hellwig <hch@lst.de> wrote:
>>>>
>>>> On Wed, Jun 23, 2021 at 02:44:34PM -0400, Qian Cai wrote:
>>>>> is_swiotlb_force_bounce at /usr/src/linux-next/./include/linux/swiotlb.h:119
>>>>>
>>>>> is_swiotlb_force_bounce() was the new function introduced in this patch here.
>>>>>
>>>>> +static inline bool is_swiotlb_force_bounce(struct device *dev)
>>>>> +{
>>>>> + return dev->dma_io_tlb_mem->force_bounce;
>>>>> +}
>>>>
>>>> To me the crash looks like dev->dma_io_tlb_mem is NULL. Can you
>>>> turn this into :
>>>>
>>>> return dev->dma_io_tlb_mem && dev->dma_io_tlb_mem->force_bounce;
>>>>
>>>> for a quick debug check?
>>>
>>> I just realized that dma_io_tlb_mem might be NULL like Christoph
>>> pointed out since swiotlb might not get initialized.
>>> However, `Unable to handle kernel paging request at virtual address
>>> dfff80000000000e` looks more like the address is garbage rather than
>>> NULL?
>>> I wonder if that's because dev->dma_io_tlb_mem is not assigned
>>> properly (which means device_initialize is not called?).
>>
>> What also looks odd is that the base "address" 0xdfff800000000000 is held in
>> a couple of registers, but the offset 0xe looks too small to match up to any
>> relevant structure member in that dereference chain :/
>
> FWIW, I've managed to trigger a NULL dereference locally when swiotlb hasn't
> been initialised but we dereference 'dev->dma_io_tlb_mem', so I think
> Christoph's suggestion is needed regardless.
Ack to that - for SWIOTLB_NO_FORCE, io_tlb_default_mem will remain NULL.
The massive jump in KernelCI baseline failures as of yesterday looks
like every arm64 machine with less than 4GB of RAM blowing up...
Robin.
> But I agree that it won't help
> with the issue reported by Qian Cai.
>
> Qian Cai: please can you share your .config and your command line?
>
> Thanks,
>
> Will
>
next prev parent reply other threads:[~2021-06-24 11:34 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-19 3:40 [PATCH v14 00/12] Restricted DMA Claire Chang
2021-06-19 3:40 ` [PATCH v14 01/12] swiotlb: Refactor swiotlb init functions Claire Chang
2021-06-22 21:02 ` Stefano Stabellini
2021-06-19 3:40 ` [PATCH v14 02/12] swiotlb: Refactor swiotlb_create_debugfs Claire Chang
2021-06-19 3:40 ` [PATCH v14 03/12] swiotlb: Set dev->dma_io_tlb_mem to the swiotlb pool used Claire Chang
2021-06-19 3:40 ` [PATCH v14 04/12] swiotlb: Update is_swiotlb_buffer to add a struct device argument Claire Chang
2021-06-19 3:40 ` [PATCH v14 05/12] swiotlb: Update is_swiotlb_active " Claire Chang
2021-06-19 3:40 ` [PATCH v14 06/12] swiotlb: Use is_swiotlb_force_bounce for swiotlb data bouncing Claire Chang
2021-06-23 16:39 ` Qian Cai
2021-06-23 18:37 ` Will Deacon
2021-06-23 18:44 ` Qian Cai
2021-06-24 5:43 ` Christoph Hellwig
2021-06-24 6:05 ` Claire Chang
2021-06-24 11:14 ` Robin Murphy
2021-06-24 11:18 ` Will Deacon
2021-06-24 11:34 ` Robin Murphy [this message]
2021-06-24 11:48 ` Will Deacon
2021-06-24 14:10 ` Qian Cai
2021-06-24 15:55 ` Konrad Rzeszutek Wilk
2021-06-24 15:58 ` Claire Chang
2021-06-24 19:20 ` Konrad Rzeszutek Wilk
2021-06-19 3:40 ` [PATCH v14 07/12] swiotlb: Move alloc_size to swiotlb_find_slots Claire Chang
2021-06-19 3:40 ` [PATCH v14 08/12] swiotlb: Refactor swiotlb_tbl_unmap_single Claire Chang
2021-06-19 3:40 ` [PATCH v14 09/12] swiotlb: Add restricted DMA alloc/free support Claire Chang
2021-06-19 3:40 ` [PATCH v14 10/12] swiotlb: Add restricted DMA pool initialization Claire Chang
2021-06-19 3:40 ` [PATCH v14 11/12] dt-bindings: of: Add restricted DMA pool Claire Chang
2021-06-19 3:40 ` [PATCH v14 12/12] of: Add plumbing for " Claire Chang
2021-06-23 8:38 ` [PATCH v14 00/12] Restricted DMA Konrad Rzeszutek Wilk
2021-06-23 9:01 ` Claire Chang
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