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From: Georgi Djakov <djakov@kernel.org>
To: Sasha Levin <sashal@kernel.org>,
	Georgi Djakov <quic_c_gdjako@quicinc.com>
Cc: stable@vger.kernel.org, rppt@linux.ibm.com,
	anshuman.khandual@arm.com, david@redhat.com, will@kernel.org,
	catalin.marinas@arm.com, hch@lst.de, akpm@linux-foundation.org,
	surenb@google.com, quic_sudaraja@quicinc.com
Subject: Re: [PATCH 5.15 2/2] arm64/mm: drop HAVE_ARCH_PFN_VALID
Date: Wed, 20 Apr 2022 19:11:10 +0300	[thread overview]
Message-ID: <f567a8cc-cd1c-9f79-eda0-a45a39383611@kernel.org> (raw)
In-Reply-To: <YmAdlNslaGbSKUj4@sashalap>


Hi Sasha,

On 20.04.22 17:49, Sasha Levin wrote:
> On Wed, Apr 20, 2022 at 05:43:41AM -0700, Georgi Djakov wrote:
>> From: Anshuman Khandual <anshuman.khandual@arm.com>
>>
>> [ Upstream commit 3de360c3fdb34fbdbaf6da3af94367d3fded95d3 ]
>>
>> CONFIG_SPARSEMEM_VMEMMAP is now the only available memory model on arm64
>> platforms and free_unused_memmap() would just return without creating any
>> holes in the memmap mapping.  There is no need for any special handling in
>> pfn_valid() and HAVE_ARCH_PFN_VALID can just be dropped.  This also moves
>> the pfn upper bits sanity check into generic pfn_valid().
> 
> It's not clear why we need this patch in stable.
> 

I added a Link: tag, pointing to the discussion where the problem is explained
in details and the suggestion to backport these patches to 5.15. But probably
this is not enough and i should have mentioned it in the commit message too.

So in short:
This is fixing a crash on systems where the RAM base address is not aligned
to the pageblock size. Only v5.15 is affected.

 > Fixes: 859a85ddf90e ("mm: remove pfn_valid_within() and CONFIG_HOLES_IN_ZONE")
 > Link: https://lore.kernel.org/r/Yl0IZWT2nsiYtqBT@linux.ibm.com

Thanks,
Georgi

  reply	other threads:[~2022-04-20 16:11 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-20 12:43 [PATCH 5.15 1/2] dma-mapping: remove bogus test for pfn_valid from dma_map_resource Georgi Djakov
2022-04-20 12:43 ` [PATCH 5.15 2/2] arm64/mm: drop HAVE_ARCH_PFN_VALID Georgi Djakov
2022-04-20 14:49   ` Sasha Levin
2022-04-20 16:11     ` Georgi Djakov [this message]
2022-04-21  6:43 ` [PATCH 5.15 1/2] dma-mapping: remove bogus test for pfn_valid from dma_map_resource Greg KH
2022-04-21  7:51   ` Georgi Djakov
2022-04-21  8:25     ` Greg KH

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