From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3B2B931D72E; Wed, 10 Jun 2026 16:52:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781110370; cv=none; b=fyEQhjTyRB8//Kuc+xNYd2GIJBnoXwghwblBDu9PcrYw4WU+DAFZsMkyXmQ300Od43I+xg/EgTExMnr1mwU58LR2HL9lfExyN3x0meH1JomdfS3PTUYoqywCMotDcM+0eUfgAq+atYnoj+VIL5DI8ww7pnMRWQgG/De8E6S+KYY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781110370; c=relaxed/simple; bh=ChZ/VzETVjFxU1t8/XJV+KvRhbiU9Z++AiHo3rLz4CY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=QA+FnxK6pjfe6/8ue18RRfhH+Q3ezh35Q6VAPY+w9Cuy+pXeeDUl4G8QApv+KK580mlimo8xJNyVjBh05EDvNQ+49LawjRF4NAhfYV45s2QAGy6DeFwJrpZYoTgG9WYAaLZD8dH2LxbziAQ1kbusBJb35SThmAPDia+gf4hc7Xk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=f/9k/Crs; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="f/9k/Crs" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0EA591F00893; Wed, 10 Jun 2026 16:52:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1781110369; bh=GW9heMHecXhASh30FDBJHV61LxuCJ+9Zw4ZSxVAvLJU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=f/9k/Crs/Cs/w01FWV3G168IrZP5ouJDnqMEHGo0bf334oHfoKVLKTMGeSW2UGEc3 Hv6wwI2teHQ15xLB66EP7kqQc8kpSmlBOPGkCgOr7gfP0iiqN+dBayT4BPoxdC9pGD tFcET8obutBk0pTGU27GfAO2EEgi3fNu3g/Fc+T92xiBgnwYpnf8e0HIedIJnLl8V3 S5B5i8BCAEdjGs7glpy22aydf3beaRoBHwiB6SPcVqeQ59JZXPBY1UQ1Fq8wITpat9 pbHz6LoiWzjQTNLR6x+I3njCqo9bvzJCB71Nh2ZqCQkKStR46Kh3OoCwDF0w+F5CYs DBGovz8VaF7Hg== From: Arnaldo Carvalho de Melo To: Namhyung Kim Cc: Ingo Molnar , Thomas Gleixner , James Clark , Jiri Olsa , Ian Rogers , Adrian Hunter , Clark Williams , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Arnaldo Carvalho de Melo , sashiko-bot , Davidlohr Bueso , "Claude Opus 4.6" Subject: [PATCH 06/11] perf sched: Fix idle-hist callchain display using wrong rb_first variant Date: Wed, 10 Jun 2026 13:52:00 -0300 Message-ID: <20260610165207.2077258-7-acme@kernel.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260610165207.2077258-1-acme@kernel.org> References: <20260610165207.2077258-1-acme@kernel.org> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Arnaldo Carvalho de Melo timehist_print_idlehist_callchain() calls rb_first_cached() on sorted_root, but the sort function (callchain_param.sort) populates it via rb_insert_color() on the plain rb_root member — not the cached variant. This means rb_leftmost is never set, so rb_first_cached() always returns NULL and the entire callchain summary is silently dropped from --idle-hist output. The original code in ba957ebb54893aca ("perf sched timehist: Show callchains for idle stat") was correct — it used struct rb_root and rb_first(). The bug was introduced when sorted_root was converted to rb_root_cached without converting the sort insertion path to use rb_insert_color_cached(). Use rb_first(&root->rb_root) to match how the tree was populated. Fixes: cb4c13a5137766c3 ("perf sched: Use cached rbtrees") Reported-by: sashiko-bot Cc: Davidlohr Bueso Cc: Namhyung Kim Acked-by: Ian Rogers Assisted-by: Claude Opus 4.6 Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-sched.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c index ded511d8518803a0..85f11d388392d316 100644 --- a/tools/perf/builtin-sched.c +++ b/tools/perf/builtin-sched.c @@ -3130,7 +3130,8 @@ static size_t timehist_print_idlehist_callchain(struct rb_root_cached *root) size_t ret = 0; FILE *fp = stdout; struct callchain_node *chain; - struct rb_node *rb_node = rb_first_cached(root); + /* sort() uses rb_insert_color() on rb_root, not rb_root_cached */ + struct rb_node *rb_node = rb_first(&root->rb_root); printf(" %16s %8s %s\n", "Idle time (msec)", "Count", "Callchains"); printf(" %.16s %.8s %.50s\n", graph_dotted_line, graph_dotted_line, -- 2.54.0