linux-kernel - Re: [PATCH] crash: Default to CRASH_DUMP=n when support for it is unlikely

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Message-ID: <ZtFoMMsS5PuFw3LF@MiWiFi-R3L-srv>
Date: Fri, 30 Aug 2024 14:35:28 +0800
From: Baoquan He <bhe@...hat.com>
To: Dave Vasilevsky <dave@...ilevsky.ca>
Cc: akpm@...ux-foundation.org, glaubitz@...sik.fu-berlin.de,
	linuxppc-dev@...ts.ozlabs.org, linux-sh@...r.kernel.org,
	mpe@...erman.id.au, kexec@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	Reimar Döffinger <Reimar.Doeffinger@....de>
Subject: Re: [PATCH] crash: Default to CRASH_DUMP=n when support for it is
 unlikely

On 08/23/24 at 08:51am, Dave Vasilevsky wrote:
> Fixes boot failures on 6.9 on PPC_BOOK3S_32 machines using
> Open Firmware. On these machines, the kernel refuses to boot
> from non-zero PHYSICAL_START, which occurs when CRASH_DUMP is on.
> 
> Since most PPC_BOOK3S_32 machines boot via Open Firmware, it should
> default to off for them. Users booting via some other mechanism
> can still turn it on explicitly.
> 
> Also defaults to CRASH_DUMP=n on sh.

The overrall looks good to me except of the CRASH_DUMP=n on sh, do you
have a comment about the reasoning since you have discussed with John?
Is it because of below config items?

arch/sh/Kconfig:
config ARCH_SUPPORTS_CRASH_DUMP
        def_bool BROKEN_ON_SMP
...
config PHYSICAL_START
        hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
        default MEMORY_START
	...

> 
> Signed-off-by: Dave Vasilevsky <dave@...ilevsky.ca>
> Reported-by: Reimar Döffinger <Reimar.Doeffinger@....de>
> Closes: https://lists.debian.org/debian-powerpc/2024/07/msg00001.html
> Fixes: 75bc255a7444 ("crash: clean up kdump related config items")
> ---
>  arch/arm/Kconfig       | 3 +++
>  arch/arm64/Kconfig     | 3 +++
>  arch/loongarch/Kconfig | 3 +++
>  arch/mips/Kconfig      | 3 +++
>  arch/powerpc/Kconfig   | 4 ++++
>  arch/riscv/Kconfig     | 3 +++
>  arch/s390/Kconfig      | 3 +++
>  arch/sh/Kconfig        | 3 +++
>  arch/x86/Kconfig       | 3 +++
>  kernel/Kconfig.kexec   | 2 +-
>  10 files changed, 29 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index 54b2bb817a7f..200995052690 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -1597,6 +1597,9 @@ config ATAGS_PROC
>  config ARCH_SUPPORTS_CRASH_DUMP
>  	def_bool y
>  
> +config ARCH_DEFAULT_CRASH_DUMP
> +	def_bool y
> +
>  config AUTO_ZRELADDR
>  	bool "Auto calculation of the decompressed kernel image address" if !ARCH_MULTIPLATFORM
>  	default !(ARCH_FOOTBRIDGE || ARCH_RPC || ARCH_SA1100)
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index a2f8ff354ca6..43e08cc8204f 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -1558,6 +1558,9 @@ config ARCH_DEFAULT_KEXEC_IMAGE_VERIFY_SIG
>  config ARCH_SUPPORTS_CRASH_DUMP
>  	def_bool y
>  
> +config ARCH_DEFAULT_CRASH_DUMP
> +	def_bool y
> +
>  config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
>  	def_bool CRASH_RESERVE
>  
> diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
> index 70f169210b52..ce232ddcd27d 100644
> --- a/arch/loongarch/Kconfig
> +++ b/arch/loongarch/Kconfig
> @@ -599,6 +599,9 @@ config ARCH_SUPPORTS_KEXEC
>  config ARCH_SUPPORTS_CRASH_DUMP
>  	def_bool y
>  
> +config ARCH_DEFAULT_CRASH_DUMP
> +	def_bool y
> +
>  config ARCH_SELECTS_CRASH_DUMP
>  	def_bool y
>  	depends on CRASH_DUMP
> diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
> index 60077e576935..b547f4304d0c 100644
> --- a/arch/mips/Kconfig
> +++ b/arch/mips/Kconfig
> @@ -2881,6 +2881,9 @@ config ARCH_SUPPORTS_KEXEC
>  config ARCH_SUPPORTS_CRASH_DUMP
>  	def_bool y
>  
> +config ARCH_DEFAULT_CRASH_DUMP
> +	def_bool y
> +
>  config PHYSICAL_START
>  	hex "Physical address where the kernel is loaded"
>  	default "0xffffffff84000000"
> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> index d7b09b064a8a..0f3c1f958eac 100644
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@ -682,6 +682,10 @@ config RELOCATABLE_TEST
>  config ARCH_SUPPORTS_CRASH_DUMP
>  	def_bool PPC64 || PPC_BOOK3S_32 || PPC_85xx || (44x && !SMP)
>  
> +config ARCH_DEFAULT_CRASH_DUMP
> +	bool
> +	default y if !PPC_BOOK3S_32
> +
>  config ARCH_SELECTS_CRASH_DUMP
>  	def_bool y
>  	depends on CRASH_DUMP
> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> index 0f3cd7c3a436..eb247b5ee569 100644
> --- a/arch/riscv/Kconfig
> +++ b/arch/riscv/Kconfig
> @@ -880,6 +880,9 @@ config ARCH_SUPPORTS_KEXEC_PURGATORY
>  config ARCH_SUPPORTS_CRASH_DUMP
>  	def_bool y
>  
> +config ARCH_DEFAULT_CRASH_DUMP
> +	def_bool y
> +
>  config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
>  	def_bool CRASH_RESERVE
>  
> diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
> index a822f952f64a..05a1fb408471 100644
> --- a/arch/s390/Kconfig
> +++ b/arch/s390/Kconfig
> @@ -275,6 +275,9 @@ config ARCH_SUPPORTS_CRASH_DUMP
>  	  This option also enables s390 zfcpdump.
>  	  See also <file:Documentation/arch/s390/zfcpdump.rst>
>  
> +config ARCH_DEFAULT_CRASH_DUMP
> +	def_bool y
> +
>  menu "Processor type and features"
>  
>  config HAVE_MARCH_Z10_FEATURES
> diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig
> index 1aa3c4a0c5b2..b04cfa23378c 100644
> --- a/arch/sh/Kconfig
> +++ b/arch/sh/Kconfig
> @@ -549,6 +549,9 @@ config ARCH_SUPPORTS_KEXEC
>  config ARCH_SUPPORTS_CRASH_DUMP
>  	def_bool BROKEN_ON_SMP
>  
> +config ARCH_DEFAULT_CRASH_DUMP
> +	def_bool n
> +
>  config ARCH_SUPPORTS_KEXEC_JUMP
>  	def_bool y
>  
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 007bab9f2a0e..aa4666bb9e9c 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -2087,6 +2087,9 @@ config ARCH_SUPPORTS_KEXEC_JUMP
>  config ARCH_SUPPORTS_CRASH_DUMP
>  	def_bool X86_64 || (X86_32 && HIGHMEM)
>  
> +config ARCH_DEFAULT_CRASH_DUMP
> +	def_bool y
> +
>  config ARCH_SUPPORTS_CRASH_HOTPLUG
>  	def_bool y
>  
> diff --git a/kernel/Kconfig.kexec b/kernel/Kconfig.kexec
> index 6c34e63c88ff..4d111f871951 100644
> --- a/kernel/Kconfig.kexec
> +++ b/kernel/Kconfig.kexec
> @@ -97,7 +97,7 @@ config KEXEC_JUMP
>  
>  config CRASH_DUMP
>  	bool "kernel crash dumps"
> -	default y
> +	default ARCH_DEFAULT_CRASH_DUMP
>  	depends on ARCH_SUPPORTS_CRASH_DUMP
>  	depends on KEXEC_CORE
>  	select VMCORE_INFO
> -- 
> 2.34.1
>