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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6320FC433FE for ; Thu, 17 Mar 2022 13:55:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234749AbiCQN5D (ORCPT ); Thu, 17 Mar 2022 09:57:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41692 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232467AbiCQN5B (ORCPT ); Thu, 17 Mar 2022 09:57:01 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 10EBE1042B2 for ; Thu, 17 Mar 2022 06:55:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1647525344; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc; bh=3qWgFKPuWbwkNXZxQSeQl0sRheg0mQTqRVZcOh+jo7o=; b=HlkCqTj8Sbwj/AFCZKt8cmnYDT56YI7ue494fWqs/FEq6k9SqlOJD8tmxL7MJIEVTLZ3Qf u1Xix47dYBaRjNg+YayLqV2adSjJV1k+2XirjszUTbwYDAYz5Ui6SvUmJB6Z9HEcAa4AW/ w/RklRWibuMTs+rdrN3wdNL1vDdddRs= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-482-Y7cZe7tNMCy7UxgEWPzCHQ-1; Thu, 17 Mar 2022 09:55:40 -0400 X-MC-Unique: Y7cZe7tNMCy7UxgEWPzCHQ-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 50D341044563; Thu, 17 Mar 2022 13:55:40 +0000 (UTC) Received: from Diego.redhat.com (unknown [10.39.208.28]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 810822011571; Thu, 17 Mar 2022 13:55:38 +0000 (UTC) From: Michael Petlan To: linux-kernel@vger.kernel.org Cc: linux-perf-users@vger.kernel.org, acme@kernel.org, jolsa@kernel.org, atrajeev@linux.vnet.ibm.com, maddy@linux.ibm.com, kjain@linux.ibm.com Subject: [PATCH] perf symbols: Fix symbol size calculation condition Date: Thu, 17 Mar 2022 14:55:36 +0100 Message-Id: <20220317135536.805-1-mpetlan@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Before this patch, the symbol end address fixup to be called, needed two conditions being met: if (prev->end == prev->start && prev->end != curr->start) Where "prev->end == prev->start" means that prev is zero-long (and thus needs a fixup) and "prev->end != curr->start" means that fixup hasn't been applied yet However, this logic is incorrect in the following situation: *curr = {rb_node = {__rb_parent_color = 278218928, rb_right = 0x0, rb_left = 0x0}, start = 0xc000000000062354, end = 0xc000000000062354, namelen = 40, type = 2 '\002', binding = 0 '\000', idle = 0 '\000', ignore = 0 '\000', inlined = 0 '\000', arch_sym = 0 '\000', annotate2 = false, name = 0x1159739e "kprobe_optinsn_page\t[__builtin__kprobes]"} *prev = {rb_node = {__rb_parent_color = 278219041, rb_right = 0x109548b0, rb_left = 0x109547c0}, start = 0xc000000000062354, end = 0xc000000000062354, namelen = 12, type = 2 '\002', binding = 1 '\001', idle = 0 '\000', ignore = 0 '\000', inlined = 0 '\000', arch_sym = 0 '\000', annotate2 = false, name = 0x1095486e "optinsn_slot"} In this case, prev->start == prev->end == curr->start == curr->end, thus the condition above thinks that "we need a fixup due to zero length of prev symbol, but it has been probably done, since the prev->end == curr->start", which is wrong. After the patch, the execution path proceeds to arch__symbols__fixup_end function which fixes up the size of prev symbol by adding page_size to its end offset. Signed-off-by: Michael Petlan --- tools/perf/util/symbol.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c index fb075aa8f8f2..dea0fc495185 100644 --- a/tools/perf/util/symbol.c +++ b/tools/perf/util/symbol.c @@ -231,7 +231,7 @@ void symbols__fixup_end(struct rb_root_cached *symbols) prev = curr; curr = rb_entry(nd, struct symbol, rb_node); - if (prev->end == prev->start && prev->end != curr->start) + if (prev->end == prev->start || prev->end != curr->start) arch__symbols__fixup_end(prev, curr); } -- 2.18.4