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 <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
Cc: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Cc: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx>
Cc: Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Dave Young <dyoung@xxxxxxxxxx>
Cc: Baoquan He <bhe@xxxxxxxxxx>
Cc: Vivek Goyal <vgoyal@xxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Keith Busch <keith.busch@xxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Qian Cai <cai@xxxxxx>
Cc: Oscar Salvador <osalvador@xxxxxxx>
Cc: Eric Biederman <ebiederm@xxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Tom Lendacky <thomas.lendacky@xxxxxxx>
Cc: Brijesh Singh <brijesh.singh@xxxxxxx>
Cc: x86@xxxxxxxxxx
Cc: kexec@xxxxxxxxxxxxxxxxxxx
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
---
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
