From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D43BCC282C3 for ; Tue, 22 Jan 2019 15:26:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A49A1217D6 for ; Tue, 22 Jan 2019 15:26:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730098AbfAVP0l (ORCPT ); Tue, 22 Jan 2019 10:26:41 -0500 Received: from faui40.informatik.uni-erlangen.de ([131.188.34.40]:49706 "EHLO faui40.informatik.uni-erlangen.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729793AbfAVP0k (ORCPT ); Tue, 22 Jan 2019 10:26:40 -0500 Received: from faui49copter1 (faui49copter1.informatik.uni-erlangen.de [131.188.42.149]) by faui40.informatik.uni-erlangen.de (Postfix) with SMTP id 3FE9E548875; Tue, 22 Jan 2019 16:26:35 +0100 (CET) Received: by faui49copter1 (sSMTP sendmail emulation); Tue, 22 Jan 2019 16:26:35 +0100 From: Andreas Ziegler To: Steven Rostedt Cc: Ingo Molnar , Masami Hiramatsu , linux-kernel@vger.kernel.org, Andreas Ziegler Subject: [PATCH v2] tracing: probeevent: Correctly update remaining space in dynamic area Date: Tue, 22 Jan 2019 16:26:34 +0100 Message-Id: <20190122152634.18957-1-andreas.ziegler@fau.de> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190122221434.419e956dd91da0516ff4cc04@kernel.org> References: <20190122221434.419e956dd91da0516ff4cc04@kernel.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit 9178412ddf5a ("tracing: probeevent: Return consumed bytes of dynamic area") improved the string fetching mechanism by returning the number of required bytes after copying the argument to the dynamic area. However, this return value is now only used to increment the pointer inside the dynamic area but misses updating the 'maxlen' variable which indicates the remaining space in the dynamic area. This means that fetch_store_string() always reads the *total* size of the dynamic area from the data_loc pointer instead of the *remaining* size (and passes it along to strncpy_from_{user,unsafe}) even if we're already about to copy data into the middle of the dynamic area. Fixes: 9178412ddf5a ("tracing: probeevent: Return consumed bytes of dynamic area") Signed-off-by: Andreas Ziegler Acked-by: Masami Hiramatsu --- v2: follow coding guidelines for braces kernel/trace/trace_probe_tmpl.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/kernel/trace/trace_probe_tmpl.h b/kernel/trace/trace_probe_tmpl.h index 5c56afc17cf8..4737bb8c07a3 100644 --- a/kernel/trace/trace_probe_tmpl.h +++ b/kernel/trace/trace_probe_tmpl.h @@ -180,10 +180,12 @@ store_trace_args(void *data, struct trace_probe *tp, struct pt_regs *regs, if (unlikely(arg->dynamic)) *dl = make_data_loc(maxlen, dyndata - base); ret = process_fetch_insn(arg->code, regs, dl, base); - if (unlikely(ret < 0 && arg->dynamic)) + if (unlikely(ret < 0 && arg->dynamic)) { *dl = make_data_loc(0, dyndata - base); - else + } else { dyndata += ret; + maxlen -= ret; + } } } -- 2.17.1