From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 B07BC2ED16E; Tue, 17 Jun 2025 15:56:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750175816; cv=none; b=KuMip9Ei7L/lsmboHThkC6nA960bfSPgrLMlOKtKe0Zlbqyrwmt+QxzHmib075WcQhoto3Pdx88wjA5c1SwLjyM0bXeXX+Haz+enat3kjcW8kCtdVv8GwE/WXiC15+Lou/gGNvRQ+KOChRWVQZTDsCju5xWqOqo6ERBF5mK5g8c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750175816; c=relaxed/simple; bh=6bfCWE4Rr4oRbfc6VqBNayYNlANscTj8esYh1v2Sdg4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=qiPCNC/j512SKoWMCdNWiS3bjUtTJEL+T8XlNW3nImJb3zJxVs08qNbusXZTsvuwvfMqL+2MzljDclaoSARZyDAiPRBSEESVNMlnYImqiFxrT8clPs2JrTpYgmfHexSNZtqQV3WoSKFGCyDSL3bzxLmr4dLksN0D1rjg/Jgy1PA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=uodpiwNT; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="uodpiwNT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 42A23C4CEE3; Tue, 17 Jun 2025 15:56:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1750175816; bh=6bfCWE4Rr4oRbfc6VqBNayYNlANscTj8esYh1v2Sdg4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uodpiwNTXFwTHtazodptuqq0gDg92Oq1vSwPRCGJjvTjDFd9Sojh12Fgo5sa9yvJm wWl2rcYzoAjAPbDVevKHRIO1ZQDOsoxGMU26/x6ROjEHMuJZ2r3dGtBNdrhdJzgCZn qiwqK7oVjXemQqTAjDevrYHMqYt0SKm/XtbltHmw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Ian Rogers , Leo Yan , Adrian Hunter , James Clark , Kan Liang , Namhyung Kim , Arnaldo Carvalho de Melo , Sasha Levin Subject: [PATCH 6.6 215/356] perf tests switch-tracking: Fix timestamp comparison Date: Tue, 17 Jun 2025 17:25:30 +0200 Message-ID: <20250617152346.861017776@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250617152338.212798615@linuxfoundation.org> References: <20250617152338.212798615@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Leo Yan [ Upstream commit 628e124404b3db5e10e17228e680a2999018ab33 ] The test might fail on the Arm64 platform with the error: # perf test -vvv "Track with sched_switch" Missing sched_switch events # The issue is caused by incorrect handling of timestamp comparisons. The comparison result, a signed 64-bit value, was being directly cast to an int, leading to incorrect sorting for sched events. The case does not fail everytime, usually I can trigger the failure after run 20 ~ 30 times: # while true; do perf test "Track with sched_switch"; done 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : FAILED! 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok 106: Track with sched_switch : FAILED! 106: Track with sched_switch : Ok 106: Track with sched_switch : Ok I used cross compiler to build Perf tool on my host machine and tested on Debian / Juno board. Generally, I think this issue is not very specific to GCC versions. As both internal CI and my local env can reproduce the issue. My Host Build compiler: # aarch64-linux-gnu-gcc --version aarch64-linux-gnu-gcc (Ubuntu 13.3.0-6ubuntu2~24.04) 13.3.0 Juno Board: # lsb_release -a No LSB modules are available. Distributor ID: Debian Description: Debian GNU/Linux 12 (bookworm) Release: 12 Codename: bookworm Fix this by explicitly returning 0, 1, or -1 based on whether the result is zero, positive, or negative. Fixes: d44bc558297222d9 ("perf tests: Add a test for tracking with sched_switch") Reviewed-by: Ian Rogers Signed-off-by: Leo Yan Cc: Adrian Hunter Cc: James Clark Cc: Kan Liang Cc: Namhyung Kim Link: https://lore.kernel.org/r/20250331172759.115604-1-leo.yan@arm.com Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Sasha Levin --- tools/perf/tests/switch-tracking.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/perf/tests/switch-tracking.c b/tools/perf/tests/switch-tracking.c index e52b031bedc5a..2c7bdf4fd55ed 100644 --- a/tools/perf/tests/switch-tracking.c +++ b/tools/perf/tests/switch-tracking.c @@ -258,7 +258,7 @@ static int compar(const void *a, const void *b) const struct event_node *nodeb = b; s64 cmp = nodea->event_time - nodeb->event_time; - return cmp; + return cmp < 0 ? -1 : (cmp > 0 ? 1 : 0); } static int process_events(struct evlist *evlist, -- 2.39.5