Commit 9cc3d0c6 authored Apr 14, 2020 by Mark Rutland Committed by Catalin Marinas Apr 15, 2020

arm64: vdso: don't free unallocated pages



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: 7c1deeeb ("arm64: compat: VDSO setup for compat layer")
Cc: <stable@vger.kernel.org> # 5.3.x-
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

parent 8f3d9f35

arch/arm64/kernel/vdso.c

+1 −12

Original line number	Diff line number	Diff line
		@@ -260,18 +260,7 @@ static int __aarch32_alloc_vdso_pages(void)
		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)

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