It used to be true that we can have busy system RAM only on the first level in the resourc tree. However, this is no longer holds for driver-managed system RAM (i.e., added via dax/kmem and virtio-mem), which gets added on lower levels.
We have two users of walk_system_ram_res(), which currently only consideres the first level: a) kernel/kexec_file.c:kexec_walk_resources() -- We properly skip IORESOURCE_SYSRAM_DRIVER_MANAGED resources via locate_mem_hole_callback(), so even after this change, we won't be placing kexec images onto dax/kmem and virtio-mem added memory. No change. b) arch/x86/kernel/crash.c:fill_up_crash_elf_data() -- we're currently not adding relevant ranges to the crash elf info, resulting in them not getting dumped via kdump. This change fixes loading a crashkernel via kexec_file_load() and including dax/kmem and virtio-mem added System RAM in the crashdump on x86-64. Note that e.g,, arm64 relies on memblock data and, therefore, always considers all added System RAM already. Let's find all busy IORESOURCE_SYSTEM_RAM resources, making the function behave like walk_system_ram_range(). Cc: Andrew Morton <[email protected]> Cc: Greg Kroah-Hartman <[email protected]> Cc: Dan Williams <[email protected]> Cc: Daniel Vetter <[email protected]> Cc: Andy Shevchenko <[email protected]> Cc: Mauro Carvalho Chehab <[email protected]> Cc: Signed-off-by: David Hildenbrand <[email protected]> Cc: Dave Young <[email protected]> Cc: Baoquan He <[email protected]> Cc: Vivek Goyal <[email protected]> Cc: Dave Hansen <[email protected]> Cc: Keith Busch <[email protected]> Cc: Michal Hocko <[email protected]> Cc: Qian Cai <[email protected]> Cc: Oscar Salvador <[email protected]> Cc: Eric Biederman <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Cc: Tom Lendacky <[email protected]> Cc: Brijesh Singh <[email protected]> Cc: [email protected] Cc: [email protected] Signed-off-by: David Hildenbrand <[email protected]> --- kernel/resource.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/resource.c b/kernel/resource.c index 627e61b0c124..4efd6e912279 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -457,7 +457,7 @@ int walk_system_ram_res(u64 start, u64 end, void *arg, { unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; - return __walk_iomem_res_desc(start, end, flags, IORES_DESC_NONE, true, + return __walk_iomem_res_desc(start, end, flags, IORES_DESC_NONE, false, arg, func); } -- 2.29.2
