From: Will Deacon <will.deacon@xxxxxxx> commit 8e4e0ac02b449297b86498ac24db5786ddd9f647 upstream. Returning an error code from futex_atomic_cmpxchg_inatomic() indicates that the caller should not make any use of *uval, and should instead act upon on the value of the error code. Although this is implemented correctly in our futex code, we needlessly copy uninitialised stack to *uval in the error case, which can easily be avoided. Signed-off-by: Will Deacon <will.deacon@xxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/arm64/include/asm/futex.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/arch/arm64/include/asm/futex.h +++ b/arch/arm64/include/asm/futex.h @@ -134,7 +134,9 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, : "memory"); uaccess_disable(); - *uval = val; + if (!ret) + *uval = val; + return ret; }
