Messages in this thread | | | Date | Tue, 26 Feb 2019 13:11:17 +0800 | From | Dave Young <> | Subject | Re: [PATCH] x86/boot/KASLR: skip the specified crashkernel reserved region |
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On 02/25/19 at 09:05pm, Baoquan He wrote: > On 02/25/19 at 10:45am, Borislav Petkov wrote: > > On Mon, Feb 25, 2019 at 03:59:56PM +0800, Pingfan Liu wrote: > > > crashkernel=x@y option may fail to reserve the required memory region if > > > KASLR puts kernel into the region. To avoid this uncertainty, making KASLR > > > skip the required region. > > > > Lemme see if I understand this correctly: supplying crashkernel=X@Y > > influences where KASLR would put the randomized kernel. And it should be > > the other way around, IMHO. crashkernel= will have to "work" with KASLR > > to find a suitable range and if the reservation at Y fails, then we tell > > the user to try the more relaxed variant crashkernel=M. > > Hmm, asking user to try crashkernel=M is an option. Users may want to > specify a region for crashkernel reservation, Just I forget in what case > they want crashkernel=x@y set. In crashkernel=x@y specified case, we may > truly need to avoid the already specified region. > > Not sure if Dave still remember it. If no need, removing it is also > good.
I do not know the exact use cases, but long time ago the kernel is not relocatable this might be a reason. Even now, there could be some non linux use cases, if the loaded binary is not relocatable then the param is still useful.
Also this is a general param instead of x86 only, some other arches still use it, and no crashkernel=X implemented.
Thanks Dave
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