On 2021/6/23 15:12, Greg KH wrote:

On Wed, Jun 23, 2021 at 02:59:59PM +0800, Kefeng Wang wrote:

quoted

Hi Greg,

There are two more patches about the ZONE_DMA[32] changes,

What ZONE_DMA changes?

See the subject, [PATCH stable v5.10 0/7] arm64: Default to 32-bit wide 
ZONE_DMA, We asked the ARM64 ZONE_DMA change backport before, link[1]

quoted

especially the
second one, both them need be backported, thanks.

Backported to where?

stable 5.10

quoted

791ab8b2e3db - arm64: Ignore any DMA offsets in the max_zone_phys()
calculation
2687275a5843 - arm64: Force NO_BLOCK_MAPPINGS if crashkernel reservation is
required

Have you tried these patches?  Where do they need to be applied to?

Yes, we tested it, without them, especially the second one, we will
meet crash when using kexec boot, also there is discussion in [2]
and [3] from Catalin.

confused,

Sorry about this, should add more information, thanks.

[1] 
https://lore.kernel.org/linux-riscv/20210303073319.2215839-1-jingxiangfeng@huawei.com/ (local)
[2] 
https://lore.kernel.org/linux-devicetree/e60d643e-4879-3fc3-737d-2c145332a6d7@arm.com/ (local)
[3] 
https://lore.kernel.org/linux-arm-kernel/20201119175556.18681-1-catalin.marinas@arm.com/ (local)

greg k-h
.