Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> writes: > Hi Dave, > > On Fri, Aug 23, 2024 at 2:54 PM Dave Vasilevsky <dave@xxxxxxxxxxxxx> 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. >> >> Signed-off-by: Dave Vasilevsky <dave@xxxxxxxxxxxxx> >> Reported-by: Reimar Döffinger <Reimar.Doeffinger@xxxxxx> >> Closes: https://lists.debian.org/debian-powerpc/2024/07/msg00001.html >> Fixes: 75bc255a7444 ("crash: clean up kdump related config items") > > Thanks for your patch! > >> --- 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 > > IMHO CRASH_DUMP should just default to n, like most kernel options, as > it enables non-trivial extra functionality: the kernel source tree has > more than 100 locations that check if CONFIG_CRASH_DUMP is enabled. > > Letting it default to enabled also conflicts with the spirit of the > help text for the symbol: > > Generate crash dump after being started by kexec. > This should be normally only set in special crash dump kernels > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > which are loaded in the main kernel with kexec-tools into > a specially reserved region and then later executed after > a crash by kdump/kexec. The crash dump kernel must be compiled > to a memory address not used by the main kernel or BIOS using > PHYSICAL_START, or it must be built as a relocatable image > (CONFIG_RELOCATABLE=y). > For more details see Documentation/admin-guide/kdump/kdump.rst > > For s390, this option also enables zfcpdump. > See also <file:Documentation/arch/s390/zfcpdump.rst> > > What is so special about CRASH_DUMP, that it should be enabled by > default? The reality is that essentially all distros enable it. Because they don't want to manage separate kernel / crash-kernel packages. So IMHO having it enabled by default in upstream does make sense, because it more closely matches what distros/users actually run. cheers _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
