arm64: kasan: avoid bad virt_to_pfn()

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@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Acked-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c
index 55d1e9205543689a6883d983dc82cb8b9eb2be6a..687a358a37337af9cf7a0d50c27b0176cfbd2012 100644 (file)
--- a/arch/arm64/mm/kasan_init.c
+++ b/arch/arm64/mm/kasan_init.c
@@ -162,7 +162,7 @@ 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