From 26701574cee6777f867f89b4a5c667817e1ee0dd Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Tue, 7 Jan 2025 11:28:58 +0100 Subject: [PATCH] s390/futex: Fix FUTEX_OP_ANDN implementation The futex operation FUTEX_OP_ANDN is supposed to implement *(int *)UADDR2 &= ~OPARG; The s390 implementation just implements an AND instead of ANDN. Add the missing bitwise not operation to oparg to fix this. This is broken since nearly 19 years, so it looks like user space is not making use of this operation. Fixes: 3363fbdd6fb4 ("[PATCH] s390: futex atomic operations") Cc: stable@vger.kernel.org Signed-off-by: Heiko Carstens Acked-by: Alexander Gordeev Signed-off-by: Alexander Gordeev --- arch/s390/include/asm/futex.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/s390/include/asm/futex.h b/arch/s390/include/asm/futex.h index eaeaeb3ff0be..752a2310f0d6 100644 --- a/arch/s390/include/asm/futex.h +++ b/arch/s390/include/asm/futex.h @@ -44,7 +44,7 @@ static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval, break; case FUTEX_OP_ANDN: __futex_atomic_op("lr %2,%1\nnr %2,%5\n", - ret, oldval, newval, uaddr, oparg); + ret, oldval, newval, uaddr, ~oparg); break; case FUTEX_OP_XOR: __futex_atomic_op("lr %2,%1\nxr %2,%5\n", -- 2.49.0