From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:58986) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a0qye-0005bM-MZ for qemu-devel@nongnu.org; Mon, 23 Nov 2015 08:16:17 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1a0qyY-0005lW-JH for qemu-devel@nongnu.org; Mon, 23 Nov 2015 08:16:16 -0500 Received: from smtp.mail.uni-mannheim.de ([134.155.96.80]:34625) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a0qyY-0005lI-CU for qemu-devel@nongnu.org; Mon, 23 Nov 2015 08:16:10 -0500 References: <1448282741-22897-1-git-send-email-rth@twiddle.net> <1448282741-22897-2-git-send-email-rth@twiddle.net> From: Stefan Weil Message-ID: <56531199.8010508@weilnetz.de> Date: Mon, 23 Nov 2015 14:16:09 +0100 MIME-Version: 1.0 In-Reply-To: <1448282741-22897-2-git-send-email-rth@twiddle.net> Content-Type: text/plain; charset=iso-8859-15 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PULL for-2.5] tcg: Fix highwater check List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Richard Henderson , qemu-devel@nongnu.org Cc: peter.maydell@linaro.org, John Clarke Am 23.11.2015 um 13:45 schrieb Richard Henderson: > From: John Clarke > > A simple typo in the variable to use when comparing vs the highwater mark. > Reports are that qemu can in fact segfault occasionally due to this mistake. > > Signed-off-by: John Clarke > Signed-off-by: Richard Henderson > --- > tcg/tcg.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/tcg/tcg.c b/tcg/tcg.c > index 682af8a..b20ed19 100644 > --- a/tcg/tcg.c > +++ b/tcg/tcg.c > @@ -2443,7 +2443,7 @@ int tcg_gen_code(TCGContext *s, tcg_insn_unit *gen_code_buf) > one operation beginning below the high water mark cannot overrun > the buffer completely. Thus we can test for overflow after > generating code without having to check during generation. */ > - if (unlikely(s->code_gen_ptr > s->code_gen_highwater)) { > + if (unlikely((void *)s->code_ptr > s->code_gen_highwater)) { > return -1; > } > } > Is a comparison of void pointers portable? Or would it be better to cast both sides to uintptr_t? Or fix the declaration of code_gen_highwater to use an uint8_t pointer and cast s->code_ptr to that type? code_gen_highwater should be fixed anyway because in translate-all a difference is calculated with it. Stefan