Re: [PATCH] crash: keep crashkernel CMA pages reserved if activation fails

[Breno Leitao]

On Wed, Nov 04, 2026 at 06:56:00AM -0800, Usama Arif wrote:
> reserve_crashkernel_cma() adds each crashkernel CMA area to
> crashk_cma_ranges[] as soon as it is declared. If the area later fails
> activation, e.g. because movablecore= put the ZONE_MOVABLE boundary
> inside it, cma_activate_area() releases the pages to the buddy allocator
> as ordinary memory. The range is still handed to the crash kernel and
> excluded from the vmcore, so kernel data that lands there is overwritten
> by the crash kernel and missing from the dump.
> 
> Mark the areas with cma_reserve_pages_on_error(), so that a failed
> activation leaves the pages reserved: lost to the first kernel, but safe
> for the crash kernel to use.
> 
> Fixes: ab475510e042 ("kdump: implement reserve_crashkernel_cma")
> Signed-off-by: Usama Arif <usama.arif@xxxxxxxxx>

Tested-by: Breno Leitao <leitao@xxxxxxxxxx>