From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:42425 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933061AbbGHHY2 (ORCPT ); Wed, 8 Jul 2015 03:24:28 -0400 Subject: Patch "s390/bpf: Fix backward jumps" has been added to the 4.1-stable tree To: holzheu@linux.vnet.ibm.com, gregkh@linuxfoundation.org, schwidefsky@de.ibm.com Cc: , From: Date: Wed, 08 Jul 2015 00:24:25 -0700 Message-ID: <1436340265228246@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled s390/bpf: Fix backward jumps to the 4.1-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: s390-bpf-fix-backward-jumps.patch and it can be found in the queue-4.1 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From b035b60ded132592055c0f9bd1cc280259c7de4b Mon Sep 17 00:00:00 2001 From: Michael Holzheu Date: Thu, 21 May 2015 15:39:31 +0200 Subject: s390/bpf: Fix backward jumps From: Michael Holzheu commit b035b60ded132592055c0f9bd1cc280259c7de4b upstream. Currently all backward jumps crash for JITed s390x eBPF programs with an illegal instruction program check and kernel panic. Because for negative values the opcode of the jump instruction is overriden by the negative branch offset an illegal instruction is generated by the JIT: 000003ff802da378: c01100000002 lgfi %r1,2 000003ff802da37e: fffffff52065 unknown <-- illegal instruction 000003ff802da384: b904002e lgr %r2,%r14 So fix this and mask the offset in order not to damage the opcode. Signed-off-by: Michael Holzheu Signed-off-by: Martin Schwidefsky Signed-off-by: Greg Kroah-Hartman --- arch/s390/net/bpf_jit_comp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/s390/net/bpf_jit_comp.c +++ b/arch/s390/net/bpf_jit_comp.c @@ -227,7 +227,7 @@ static inline void reg_set_seen(struct b ({ \ /* Branch instruction needs 6 bytes */ \ int rel = (addrs[i + off + 1] - (addrs[i + 1] - 6)) / 2;\ - _EMIT6(op1 | reg(b1, b2) << 16 | rel, op2 | mask); \ + _EMIT6(op1 | reg(b1, b2) << 16 | (rel & 0xffff), op2 | mask); \ REG_SET_SEEN(b1); \ REG_SET_SEEN(b2); \ }) Patches currently in stable-queue which might be from holzheu@linux.vnet.ibm.com are queue-4.1/s390-kdump-fix-regset_vx_low-vector-register-elf-notes.patch queue-4.1/s390-bpf-fix-backward-jumps.patch