From patchwork Wed Apr 19 21:41:40 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Beau Belgrave X-Patchwork-Id: 13217445 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9FEC4C77B73 for ; Wed, 19 Apr 2023 21:41:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231251AbjDSVlv (ORCPT ); Wed, 19 Apr 2023 17:41:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59756 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229721AbjDSVlu (ORCPT ); Wed, 19 Apr 2023 17:41:50 -0400 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 5467126AC; Wed, 19 Apr 2023 14:41:49 -0700 (PDT) Received: from W11-BEAU-MD.localdomain (unknown [76.135.27.212]) by linux.microsoft.com (Postfix) with ESMTPSA id B751B21C2059; Wed, 19 Apr 2023 14:41:48 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com B751B21C2059 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1681940508; bh=IXjbGEskcNTff4+aJt5LnXLwyuaiOG5Sy+TvmAmP5hs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bJWkt+4FpnNq6+JLhnjsXDtJlA0zm0JkaqCOonqtFKcGZIYkgg0C8SxZ5tcEjfr0L V4Dd419sNbn43J6DhSBZC0vHhJSwfFACAxI/OWHRHTeoixg2aE8X3Gp5SDuA4li4u5 4FzMs6X6Ae+YS7FeVgLyDr6UUEYL9hx2eO/e203s= From: Beau Belgrave To: rostedt@goodmis.org, mhiramat@kernel.org, dcook@linux.microsoft.com, alanau@linux.microsoft.com Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Subject: [PATCH 2/2] tracing: Fix print_fields() for __dyn_loc/__rel_loc Date: Wed, 19 Apr 2023 14:41:40 -0700 Message-Id: <20230419214140.4158-3-beaub@linux.microsoft.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230419214140.4158-1-beaub@linux.microsoft.com> References: <20230419214140.4158-1-beaub@linux.microsoft.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-trace-kernel@vger.kernel.org Both print_fields() and print_array() do not handle if dynamic data ends at the last byte of the payload for both __dyn_loc and __rel_loc field types. For __rel_loc, the offset was off by 4 bytes, leading to incorrect strings and data being printed out. In print_array() the buffer pos was missed from being advanced, which results in the first payload byte being used as the offset base instead of the field offset. Advance __rel_loc offset by 4 to ensure correct offset and advance pos to the field offset to ensure correct data is displayed when printing arrays. Change >= to > when checking if data is in-bounds, since it's valid for dynamic data to include the last byte of the payload. Example outputs for event format: field:unsigned short common_type; offset:0; size:2; signed:0; field:unsigned char common_flags; offset:2; size:1; signed:0; field:unsigned char common_preempt_count; offset:3; size:1; signed:0; field:int common_pid; offset:4; size:4; signed:1; field:__rel_loc char text[]; offset:8; size:4; signed:1; Output before: tp_rel_loc: text= Output after: tp_rel_loc: text=Test Fixes: 80a76994b2d8 ("tracing: Add "fields" option to show raw trace event fields") Reported-by: Doug Cook Signed-off-by: Beau Belgrave --- kernel/trace/trace_output.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c index 780c6971c944..952cc8aa8e59 100644 --- a/kernel/trace/trace_output.c +++ b/kernel/trace/trace_output.c @@ -819,13 +819,15 @@ static void print_array(struct trace_iterator *iter, void *pos, len = *(int *)pos >> 16; if (field) - offset += field->offset; + offset += field->offset + sizeof(int); - if (offset + len >= iter->ent_size) { + if (offset + len > iter->ent_size) { trace_seq_puts(&iter->seq, ""); return; } + pos = (void *)iter->ent + offset; + for (i = 0; i < len; i++, pos++) { if (i) trace_seq_putc(&iter->seq, ','); @@ -861,9 +863,9 @@ static void print_fields(struct trace_iterator *iter, struct trace_event_call *c len = *(int *)pos >> 16; if (field->filter_type == FILTER_RDYN_STRING) - offset += field->offset; + offset += field->offset + sizeof(int); - if (offset + len >= iter->ent_size) { + if (offset + len > iter->ent_size) { trace_seq_puts(&iter->seq, ""); break; }