[PATCH 1/2] Revert "powerpc/kasan: Fix shadow pages allocation failure"

Subsystems: kasan, linux for powerpc (32-bit and 64-bit), the rest

STALE2208d LANDED

Landed in mainline as b506923ee44a on 2020-07-15.

3 messages, 2 authors, 2020-07-16 · open the first message on its own page

[PATCH 1/2] Revert "powerpc/kasan: Fix shadow pages allocation failure"

From: Christophe Leroy <hidden>
Date: 2020-07-02 11:52:08

This reverts commit d2a91cef9bbdeb87b7449fdab1a6be6000930210.

This commit moved too much work in kasan_init(). The allocation
of shadow pages has to be moved for the reason explained in that
patch, but the allocation of page tables still need to be done
before switching to the final hash table.

First revert the incorrect commit, following patch redoes it
properly.

Reported-by: Erhard F. <redacted>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=208181
Fixes: d2a91cef9bbd ("powerpc/kasan: Fix shadow pages allocation failure")
Cc: stable@vger.kernel.org
Signed-off-by: Christophe Leroy <redacted>
---
 arch/powerpc/include/asm/kasan.h      | 2 ++
 arch/powerpc/mm/init_32.c             | 2 ++
 arch/powerpc/mm/kasan/kasan_init_32.c | 4 +---
 3 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/include/asm/kasan.h b/arch/powerpc/include/asm/kasan.h
index be85c7005fb1..d635b96c7ea6 100644
--- a/arch/powerpc/include/asm/kasan.h
+++ b/arch/powerpc/include/asm/kasan.h

@@ -27,10 +27,12 @@
 
 #ifdef CONFIG_KASAN
 void kasan_early_init(void);
+void kasan_mmu_init(void);
 void kasan_init(void);
 void kasan_late_init(void);
 #else
 static inline void kasan_init(void) { }
+static inline void kasan_mmu_init(void) { }
 static inline void kasan_late_init(void) { }
 #endif

diff --git a/arch/powerpc/mm/init_32.c b/arch/powerpc/mm/init_32.c
index 5a5469eb3174..bf1717f8d5f4 100644
--- a/arch/powerpc/mm/init_32.c
+++ b/arch/powerpc/mm/init_32.c

@@ -171,6 +171,8 @@ void __init MMU_init(void)
 	btext_unmap();
 #endif
 
+	kasan_mmu_init();
+
 	setup_kup();
 
 	/* Shortly after that, the entire linear mapping will be available */

diff --git a/arch/powerpc/mm/kasan/kasan_init_32.c b/arch/powerpc/mm/kasan/kasan_init_32.c
index 0760e1e754e4..4813c6d50889 100644
--- a/arch/powerpc/mm/kasan/kasan_init_32.c
+++ b/arch/powerpc/mm/kasan/kasan_init_32.c

@@ -117,7 +117,7 @@ static void __init kasan_unmap_early_shadow_vmalloc(void)
 	kasan_update_early_region(k_start, k_end, __pte(0));
 }
 
-static void __init kasan_mmu_init(void)
+void __init kasan_mmu_init(void)
 {
 	int ret;
 	struct memblock_region *reg;

@@ -146,8 +146,6 @@ static void __init kasan_mmu_init(void)
 
 void __init kasan_init(void)
 {
-	kasan_mmu_init();
-
 	kasan_remap_early_shadow_ro();
 
 	clear_page(kasan_early_shadow_page);

-- 
2.25.0

[PATCH 2/2] powerpc/kasan: Fix shadow pages allocation failure

From: Christophe Leroy <hidden>
Date: 2020-07-02 11:52:12

Doing kasan pages allocation in MMU_init is too early, kernel doesn't
have access yet to the entire memory space and memblock_alloc() fails
when the kernel is a bit big.

Do it from kasan_init() instead.

Reported-by: Erhard F. <redacted>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=208181
Fixes: 2edb16efc899 ("powerpc/32: Add KASAN support")
Fixes: d2a91cef9bbd ("powerpc/kasan: Fix shadow pages allocation failure")
Cc: stable@vger.kernel.org
Signed-off-by: Christophe Leroy <redacted>
---
 arch/powerpc/mm/kasan/kasan_init_32.c | 25 +++++++++++++------------
 1 file changed, 13 insertions(+), 12 deletions(-)

diff --git a/arch/powerpc/mm/kasan/kasan_init_32.c b/arch/powerpc/mm/kasan/kasan_init_32.c
index 4813c6d50889..019b0c0bbbf3 100644
--- a/arch/powerpc/mm/kasan/kasan_init_32.c
+++ b/arch/powerpc/mm/kasan/kasan_init_32.c

@@ -120,11 +120,24 @@ static void __init kasan_unmap_early_shadow_vmalloc(void)
 void __init kasan_mmu_init(void)
 {
 	int ret;
+
+	if (early_mmu_has_feature(MMU_FTR_HPTE_TABLE) ||
+	    IS_ENABLED(CONFIG_KASAN_VMALLOC)) {
+		ret = kasan_init_shadow_page_tables(KASAN_SHADOW_START, KASAN_SHADOW_END);
+
+		if (ret)
+			panic("kasan: kasan_init_shadow_page_tables() failed");
+	}
+}
+
+void __init kasan_init(void)
+{
 	struct memblock_region *reg;
 
 	for_each_memblock(memory, reg) {
 		phys_addr_t base = reg->base;
 		phys_addr_t top = min(base + reg->size, total_lowmem);
+		int ret;
 
 		if (base >= top)
 			continue;

@@ -134,18 +147,6 @@ void __init kasan_mmu_init(void)
 			panic("kasan: kasan_init_region() failed");
 	}
 
-	if (early_mmu_has_feature(MMU_FTR_HPTE_TABLE) ||
-	    IS_ENABLED(CONFIG_KASAN_VMALLOC)) {
-		ret = kasan_init_shadow_page_tables(KASAN_SHADOW_START, KASAN_SHADOW_END);
-
-		if (ret)
-			panic("kasan: kasan_init_shadow_page_tables() failed");
-	}
-
-}
-
-void __init kasan_init(void)
-{
 	kasan_remap_early_shadow_ro();
 
 	clear_page(kasan_early_shadow_page);

-- 
2.25.0

Re: [PATCH 1/2] Revert "powerpc/kasan: Fix shadow pages allocation failure"

From: Michael Ellerman <hidden>
Date: 2020-07-16 12:55:59

On Thu, 2 Jul 2020 11:52:02 +0000 (UTC), Christophe Leroy wrote:

This reverts commit d2a91cef9bbdeb87b7449fdab1a6be6000930210.

This commit moved too much work in kasan_init(). The allocation
of shadow pages has to be moved for the reason explained in that
patch, but the allocation of page tables still need to be done
before switching to the final hash table.

[...]

Applied to powerpc/next.

[1/2] Revert "powerpc/kasan: Fix shadow pages allocation failure"
      https://git.kernel.org/powerpc/c/b506923ee44ae87fc9f4de16b53feb313623e146
[2/2] powerpc/kasan: Fix shadow pages allocation failure
      https://git.kernel.org/powerpc/c/41ea93cf7ba4e0f0cc46ebfdda8b6ff27c67bc91

cheers

`h`	back out one level
`j`	next message in thread
`k`	previous message in thread
`l`	drill in
`Esc`	close help / fold thread tree
`?`	toggle this help