From: John David Anglin <dave.anglin@bell.net> stable inclusion from stable-v5.10.89 commit 5deeb9ad598b2b3b79c8d1455a276b3d9a8bac31 bugzilla: 186140 https://gitee.com/openeuler/kernel/issues/I4S8HA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit 8f66fce0f46560b9e910787ff7ad0974441c4f9c upstream. The completer in the "or,ev %r1,%r30,%r30" instruction is reversed, so we are not clipping the LWS number when we are called from a 32-bit process (W=0). We need to nulify the following depdi instruction when the least-significant bit of %r30 is 1. If the %r20 register is not clipped, a user process could perform a LWS call that would branch to an undefined location in the kernel and potentially crash the machine. Signed-off-by: John David Anglin <dave.anglin@bell.net> Cc: stable@vger.kernel.org # 4.19+ Signed-off-by: Helge Deller <deller@gmx.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Chen Jun <chenjun102@huawei.com> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> --- arch/parisc/kernel/syscall.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/parisc/kernel/syscall.S b/arch/parisc/kernel/syscall.S index 322503780db6..4e53515cf81f 100644 --- a/arch/parisc/kernel/syscall.S +++ b/arch/parisc/kernel/syscall.S @@ -478,7 +478,7 @@ lws_start: extrd,u %r1,PSW_W_BIT,1,%r1 /* sp must be aligned on 4, so deposit the W bit setting into * the bottom of sp temporarily */ - or,ev %r1,%r30,%r30 + or,od %r1,%r30,%r30 /* Clip LWS number to a 32-bit value for 32-bit processes */ depdi 0, 31, 32, %r20 -- 2.20.1