[PATCH for 4.9 29/39] arm64: kasan: avoid bad virt_to_pfn()

From	"Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com>
Newsgroups	linux.kernel
Subject	[PATCH for 4.9 29/39] arm64: kasan: avoid bad virt_to_pfn()
Date	2017-09-18 02:50 +0200
Message-ID	<uqSq7-72l-35@gated-at.bofh.it> (permalink)
References	<uqSq5-72l-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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From: Mark Rutland <mark.rutland@arm.com>

[ 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@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>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
---
 arch/arm64/mm/kasan_init.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c
index 757009daa9ed..ff43da269fe8 100644
--- 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
-- 
2.11.0

Thread

[PATCH for 4.9 18/39] iommu/exynos: Block SYSMMU while invalidating  FLPD cache "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com> - 2017-09-18 02:50 +0200
  [PATCH for 4.9 27/39] x86/acpi: Restore the order of CPU IDs "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com> - 2017-09-18 02:50 +0200
  [PATCH for 4.9 22/39] netfilter: nfnl_cthelper: fix incorrect  helper->expect_class_max "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com> - 2017-09-18 02:50 +0200
  [PATCH for 4.9 35/39] xfs: remove kmem_zalloc_greedy "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com> - 2017-09-18 02:50 +0200
  [PATCH for 4.9 31/39] rds: ib: add error handle "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com> - 2017-09-18 02:50 +0200
  [PATCH for 4.9 24/39] nfs: make nfs4_cb_sv_ops static "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com> - 2017-09-18 02:50 +0200
  [PATCH for 4.9 32/39] md/raid10: submit bio directly to replacement  disk "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com> - 2017-09-18 02:50 +0200
  [PATCH for 4.9 38/39] ARM: dts: BCM5301X: Fix memory start address "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com> - 2017-09-18 02:50 +0200
  [PATCH for 4.9 29/39] arm64: kasan: avoid bad virt_to_pfn() "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com> - 2017-09-18 02:50 +0200
  [PATCH for 4.9 39/39] tools/power turbostat: bugfix: GFXMHz column  not changing "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com> - 2017-09-18 02:50 +0200
  [PATCH for 4.9 20/39] MIPS: smp-cps: Fix retrieval of VPE mask on big  endian CPUs "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com> - 2017-09-18 02:50 +0200
  [PATCH for 4.9 28/39] iommu/io-pgtable-arm: Check for leaf entry  before dereferencing it "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com> - 2017-09-18 02:50 +0200
  [PATCH for 4.9 23/39] parisc: perf: Fix potential NULL pointer  dereference "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com> - 2017-09-18 02:50 +0200
  [PATCH for 4.9 34/39] i2c: meson: fix wrong variable usage in  meson_i2c_put_data "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com> - 2017-09-18 02:50 +0200
  [PATCH for 4.9 36/39] ASoC: wm_adsp: Return an error on write to a  disabled volatile control "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com> - 2017-09-18 02:50 +0200
  [PATCH for 4.9 25/39] ibmvnic: Free tx/rx scrq pointer array when  releasing sub-crqs "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com> - 2017-09-18 02:50 +0200
  [PATCH for 4.9 33/39] netfilter: nf_tables: set pktinfo->thoff at AH  header if found "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com> - 2017-09-18 02:50 +0200
  [PATCH for 4.9 37/39] libata: transport: Remove circular dependency  at free time "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com> - 2017-09-18 02:50 +0200

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