From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: [PATCH] net: bpf_jit: fix BPF_S_ALU_AND_K compilation Date: Sat, 31 Mar 2012 12:23:04 +0200 Message-ID: <1333189384.2325.3388.camel@edumazet-glaptop> References: <40f4b91c5200771f223966f368095c63.squirrel@webmail.greenhost.nl> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, stable@vger.kernel.org, linux-kernel@vger.kernel.org To: Indan Zupancic Return-path: In-Reply-To: <40f4b91c5200771f223966f368095c63.squirrel@webmail.greenhost.nl> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Sat, 2012-03-31 at 20:52 +1100, Indan Zupancic wrote: > Hello, > > Finally, after much searching I found one little bug. > > [PATCH] net: bpf_jit: fix BPF_S_ALU_AND_K compilation > > Small typo resulted in bad code generation for certain > values of K for the BPF_S_ALU_AND_K instruction. > > Signed-off-by: Indan Zupancic > --- > > diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c > index 7c1b765..28bc807 100644 > --- a/arch/x86/net/bpf_jit_comp.c > +++ b/arch/x86/net/bpf_jit_comp.c > @@ -289,7 +289,7 @@ void bpf_jit_compile(struct sk_filter *fp) > EMIT2(0x24, K & 0xFF); /* and imm8,%al */ > } else if (K >= 0xFFFF0000) { > EMIT2(0x66, 0x25); /* and imm16,%ax */ > - EMIT2(K, 2); > + EMIT(K, 2); > } else { > EMIT1_off32(0x25, K); /* and imm32,%eax */ > } > > Thanks but it was already fixed. commit 1d24fb3684f347226747c6b11ea426b7b992694e Author: zhuangfeiran@ict.ac.cn Date: Wed Mar 28 23:27:00 2012 +0000 x86 bpf_jit: fix a bug in emitting the 16-bit immediate operand of AND When K >= 0xFFFF0000, AND needs the two least significant bytes of K as its operand, but EMIT2() gives it the least significant byte of K and 0x2. EMIT() should be used here to replace EMIT2(). Signed-off-by: Feiran Zhuang Acked-by: Eric Dumazet Signed-off-by: David S. Miller