[PATCH 5.5 45/65] arm64: vdso: dont free unallocated pages

[Greg Kroah-Hartman]

From: Mark Rutland <mark.rutland@xxxxxxx>

commit 9cc3d0c6915aee5140f8335d41bbc3ff1b79aa4e upstream.

The aarch32_vdso_pages[] array never has entries allocated in the C_VVAR
or C_VDSO slots, and as the array is zero initialized these contain
NULL.

However in __aarch32_alloc_vdso_pages() when
aarch32_alloc_kuser_vdso_page() fails we attempt to free the page whose
struct page is at NULL, which is obviously nonsensical.

This patch removes the erroneous page freeing.

Fixes: 7c1deeeb0130 ("arm64: compat: VDSO setup for compat layer")
Cc: <stable@xxxxxxxxxxxxxxx> # 5.3.x-
Cc: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
Acked-by: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Mark Rutland <mark.rutland@xxxxxxx>
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 arch/arm64/kernel/vdso.c |   13 +------------
 1 file changed, 1 insertion(+), 12 deletions(-)

--- a/arch/arm64/kernel/vdso.c
+++ b/arch/arm64/kernel/vdso.c
@@ -260,18 +260,7 @@ static int __aarch32_alloc_vdso_pages(vo
 	if (ret)
 		return ret;
 
-	ret = aarch32_alloc_kuser_vdso_page();
-	if (ret) {
-		unsigned long c_vvar =
-			(unsigned long)page_to_virt(aarch32_vdso_pages[C_VVAR]);
-		unsigned long c_vdso =
-			(unsigned long)page_to_virt(aarch32_vdso_pages[C_VDSO]);
-
-		free_page(c_vvar);
-		free_page(c_vdso);
-	}
-
-	return ret;
+	return aarch32_alloc_kuser_vdso_page();
 }
 #else
 static int __aarch32_alloc_vdso_pages(void)