Hi Greg, On Fri, Oct 06, 2017 at 10:52:04AM +0200, Greg Kroah-Hartman wrote: > 4.9-stable review patch. If anyone has any objections, please let me know. I'm a little confused as to why this is being backported, given it wasn't Cc'd stable or marked as a fix. The lm_alias() helper was only introduced in v4.10, and I don't recall seeing that backported. What's going on here? Thanks, Mark. > > ------------------ > > From: Mark Rutland <mark.rutland@xxxxxxx> > > > [ Upstream commit b0de0ccc8b9edd8846828e0ecdc35deacdf186b0 ] > > Booting a v4.11-rc1 kernel with DEBUG_VIRTUAL and KASAN enabled produces > the following splat (trimmed for brevity): > > [ 0.000000] virt_to_phys used for non-linear address: ffff200008080000 (0xffff200008080000) > [ 0.000000] WARNING: CPU: 0 PID: 0 at arch/arm64/mm/physaddr.c:14 __virt_to_phys+0x48/0x70 > [ 0.000000] PC is at __virt_to_phys+0x48/0x70 > [ 0.000000] LR is at __virt_to_phys+0x48/0x70 > [ 0.000000] Call trace: > [ 0.000000] [<ffff2000080b1ac0>] __virt_to_phys+0x48/0x70 > [ 0.000000] [<ffff20000a03b86c>] kasan_init+0x1c0/0x498 > [ 0.000000] [<ffff20000a034018>] setup_arch+0x2fc/0x948 > [ 0.000000] [<ffff20000a030c68>] start_kernel+0xb8/0x570 > [ 0.000000] [<ffff20000a0301e8>] __primary_switched+0x6c/0x74 > > This is because we use virt_to_pfn() on a kernel image address when > trying to figure out its nid, so that we can allocate its shadow from > the same node. > > As with other recent changes, this patch uses lm_alias() to solve this. > > We could instead use NUMA_NO_NODE, as x86 does for all shadow > allocations, though we'll likely want the "real" memory shadow to be > backed from its corresponding nid anyway, so we may as well be > consistent and find the nid for the image shadow. > > Cc: Catalin Marinas <catalin.marinas@xxxxxxx> > Cc: Will Deacon <will.deacon@xxxxxxx> > Acked-by: Laura Abbott <labbott@xxxxxxxxxx> > Signed-off-by: Mark Rutland <mark.rutland@xxxxxxx> > Signed-off-by: Will Deacon <will.deacon@xxxxxxx> > Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > --- > arch/arm64/mm/kasan_init.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > --- a/arch/arm64/mm/kasan_init.c > +++ b/arch/arm64/mm/kasan_init.c > @@ -153,7 +153,7 @@ void __init kasan_init(void) > clear_pgds(KASAN_SHADOW_START, KASAN_SHADOW_END); > > vmemmap_populate(kimg_shadow_start, kimg_shadow_end, > - pfn_to_nid(virt_to_pfn(_text))); > + pfn_to_nid(virt_to_pfn(lm_alias(_text)))); > > /* > * vmemmap_populate() has populated the shadow region that covers the > >