On Mon, Mar 22, 2021 at 05:01:58PM +0100, David Hildenbrand wrote: > 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
"...fixes..." effectively means to me that Fixes tag should be provided. > 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 > -- With Best Regards, Andy Shevchenko
