From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alexei Starovoitov , Jan Seiffert , Eric Dumazet , "David S. Miller" Subject: [PATCH 3.4 04/13] x86: bpf_jit: support negative offsets Date: Fri, 28 Mar 2014 10:31:54 -0700 Message-Id: <20140328173053.660558137@linuxfoundation.org> In-Reply-To: <20140328173053.049244535@linuxfoundation.org> References: <20140328173053.049244535@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alexei Starovoitov commit fdfaf64e75397567257e1051931f9a3377360665 upstream. Commit a998d4342337 claimed to introduce negative offset support to x86 jit, but it couldn't be working, since at the time of the execution of LD+ABS or LD+IND instructions via call into bpf_internal_load_pointer_neg_helper() the %edx (3rd argument of this func) had junk value instead of access size in bytes (1 or 2 or 4). Store size into %edx instead of %ecx (what original commit intended to do) Fixes: a998d4342337 ("bpf jit: Let the x86 jit handle negative offsets") Signed-off-by: Alexei Starovoitov Cc: Jan Seiffert Cc: Eric Dumazet Acked-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- arch/x86/net/bpf_jit.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/x86/net/bpf_jit.S +++ b/arch/x86/net/bpf_jit.S @@ -140,7 +140,7 @@ bpf_slow_path_byte_msh: push %r9; \ push SKBDATA; \ /* rsi already has offset */ \ - mov $SIZE,%ecx; /* size */ \ + mov $SIZE,%edx; /* size */ \ call bpf_internal_load_pointer_neg_helper; \ test %rax,%rax; \ pop SKBDATA; \