3.16.54-rc1 review patch. If anyone has any objections, please let me know.
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From: Mark Rutland mark.rutland@arm.com
commit c80ed088a519da53f27b798a69748eaabc66aadf upstream.
The vdso tries to check for a NULL res pointer in __kernel_clock_getres, but only checks the lower 32 bits as is uses CBZ on the W register the res pointer is held in.
Thus, if the res pointer happened to be aligned to a 4GiB boundary, we'd spuriously skip storing the timespec to it, while returning a zero error code to the caller.
Prevent this by checking the whole pointer, using CBZ on the X register the res pointer is held in.
Fixes: 9031fefde6f2ac1d ("arm64: VDSO support") Signed-off-by: Mark Rutland mark.rutland@arm.com Reported-by: Andrew Pinski apinski@cavium.com Reported-by: Mark Salyzyn salyzyn@android.com Cc: Catalin Marinas catalin.marinas@arm.com Cc: Will Deacon will.deacon@arm.com Signed-off-by: Will Deacon will.deacon@arm.com Signed-off-by: Ben Hutchings ben@decadent.org.uk --- arch/arm64/kernel/vdso/gettimeofday.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/arm64/kernel/vdso/gettimeofday.S +++ b/arch/arm64/kernel/vdso/gettimeofday.S @@ -186,7 +186,7 @@ ENTRY(__kernel_clock_getres) b.ne 4f ldr x2, 6f 2: - cbz w1, 3f + cbz x1, 3f stp xzr, x2, [x1]
3: /* res == NULL. */