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From: Guillaume Tucker <>
To: Mike Rapoport <>,
	Andrea Arcangeli <>
Cc: Andrew Morton <>,
	Stephen Rothwell <>,,
	"" <>,,,
	Mike Rapoport <>, Baoquan He <>
Subject: Re: kernelci/staging-next bisection: sleep.login on rk3288-rock2-square #2286-staging
Date: Tue, 12 Jan 2021 11:10:28 +0000	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

On 12/01/2021 10:53, Guillaume Tucker wrote:
> On 05/01/2021 09:13, Mike Rapoport wrote:
>> On Sun, Jan 03, 2021 at 03:09:14PM -0500, Andrea Arcangeli wrote:
>>> Hello Mike,
>>> On Sun, Jan 03, 2021 at 03:47:53PM +0200, Mike Rapoport wrote:
>>>> Thanks for the logs, it seems that implicitly adding reserved regions to
>>>> memblock.memory wasn't that bright idea :)
>>> Would it be possible to somehow clean up the hack then?
>>> The only difference between the clean solution and the hack is that
>>> the hack intended to achieved the exact same, but without adding the
>>> reserved regions to memblock.memory.
>> I didn't consider adding reserved regions to memblock.memory as a clean
>> solution, this was still a hack, but I didn't think that things are that
>> fragile.
>> I still think we cannot rely on memblock.reserved to detect
>> memory/zone/node sizes and the boot failure reported here confirms this.
>>> The comment on that problematic area says the reserved area cannot be
>>> used for DMA because of some unexplained hw issue, and that doing so
>>> prevents booting, but since the area got reserved, even with the clean
>>> solution, it shouldn't have never been used for DMA?
>>> So I can only imagine that the physical memory region is way more
>>> problematic than just for DMA. It sounds like that anything that
>>> touches it, including the CPU, will hang the system, not just DMA. It
>>> sounds somewhat similar to the other e820 direct mapping issue on x86?
>> My understanding is that the boot failed because when I implicitly added
>> the reserved region to memblock.memory the memory size seen by
>> free_area_init() jumped from 2G to 4G because the reserved area was close
>> to 4G. The very first allocation would get a chunk from slightly below of
>> 4G and as there is no real memory there, the kernel would crash.
>>> If you want to test the hack on the arm board to check if it boots you
>>> can use the below commit:
>> My take is your solution would boot with this memory configuration, but I
>> still don't think that using memblock.reserved for zone/node sizing is
>> correct.
> The rk3288 platform has now been failing to boot for nearly a
> month on linux-next:
> Until a fix or a new version of this patch is made, would it be
> possible to drop it or revert it so the platform become usable
> again?
> Or if you want, I can make a cleaned-up version of my hack to
> ignore the problematic region if you still need your patch to be
> on linux-next, but that would probably be less than ideal.

By the way, another bisection found that this commit is also
breaking tegra124-nyan-big but only with both CONFIG_EFI=y
CONFIG_ARM_LPAE=y enabled:

The plain multi_v7_defconfig is booting fine:

I haven't looked into this one or tried to make it boot like
rk3288, but please let me know if there's anything there that can
be done to help.


  reply	other threads:[~2021-01-12 11:11 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <>
2020-12-11 21:53 ` kernelci/staging-next bisection: sleep.login on rk3288-rock2-square #2286-staging Guillaume Tucker
2020-12-13  8:23   ` Mike Rapoport
2020-12-18 21:59     ` Guillaume Tucker
2021-01-03 13:47       ` Mike Rapoport
2021-01-03 20:09         ` Andrea Arcangeli
2021-01-05  9:13           ` Mike Rapoport
2021-01-12 10:53             ` Guillaume Tucker
2021-01-12 11:10               ` Guillaume Tucker [this message]
2021-01-12 12:06               ` Mike Rapoport

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