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 0400633C1B6; Thu, 3 Sep 2026 23:25:07 +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=1788477909; cv=none; b=JbVRACXmXd5V3VNAfvkiEsAtIgzr4W0S8Q345VWSizeP291V7YX8mFARMvPRGWCKu3tcQAQDt0ZX0e2BCa8sbc6XPKJBOmYJSfFvkVKNeSnI2CQ2qt9RhcmIC3ITWVcb94yM1unwQylg6gVEDM1cHo0wxRGHpNm1pBXvzE1op9o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788477909; c=relaxed/simple; bh=6OAuvrdzd2ZNTwj7UpXxxD0LsMcuEQ2k1hWXgR9BA4g=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type; b=NswfCSG0rWHsVPHZKxskTR+kXoOi4LjIi/7jB55wNK5hiA0tZRvk3vE94cnzMqL7tGrzYi0VYwDkLqHXdG9xI6IuSxUj8zHCSac9yeSMiJDBCeMzFB6mMfo3ldTPXN3cBP+8mYZP5GHUstm259+sdsvvdVGoGPS/t3eiXh/ukoM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=KyEjKAxC; 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="KyEjKAxC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5A9311F000E9; Thu, 3 Sep 2026 23:25:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788477907; bh=C0kPI2M93Ze8THghUXdRhJZCUAdeQJlJKvwixiYVDh8=; h=From:To:Cc:Subject:Date; b=KyEjKAxCMTDKI8R+55O6pUvBC7piDhYtOnmTukmsLa6g+mojRBc0jQfHimYKpnrSS C2RUlx2PmF83N3i14QKgYvjUyEczKm6YkGHDLAas8rTFoOSiW/vp35pi8/4BegkkXA aXUOdkHrE0w/SWri7/s1lL8tSOZdytrPRL7Y6nrYvzGddSVD9rJlqA8pim9OERLWZ+ mZDiXwsaVydrNyigaeez1+eHg9ZhXM3uUookh0ebB7vy1KMiiWCIGqBtWnz5yBzyM6 QUtzMq75fiGjM5h1HEGL2utTD+Ii1k5OtPRVj3hyOiXApqGx8yy7aAx24Lbkmxnzjg E8nGolQHttDJA== From: "Masami Hiramatsu (Google)" To: Steven Rostedt , Masami Hiramatsu Cc: Mathieu Desnoyers , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Subject: [PATCH] tracing: Fix to avoid creating trace instances with duplicate names Date: Fri, 4 Sep 2026 08:25:04 +0900 Message-ID: <178847790399.283263.5313150997200138426.stgit@devnote2> X-Mailer: git-send-email 2.43.0 User-Agent: StGit/0.19 Precedence: bulk X-Mailing-List: linux-trace-kernel@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: Masami Hiramatsu (Google) Since commit e645535a954a ("tracing: Add option to use memmapped memory for trace boot instance") changed trace_array_get_by_name() to trace_array_create_systems(), enable_instances() does not reuse the same name instance. Therefore, if an administrator mistakenly specifies multiple `trace_instance=` options with duplicate names, all are created but only the first is accessible via tracefs. Check whether an instance with the same name already exists before creating a new one, and reject duplicates with a warning. Fixes: e645535a954a ("tracing: Add option to use memmapped memory for trace boot instance") Signed-off-by: Masami Hiramatsu (Google) --- kernel/trace/trace.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index a946e0183fd1..536e71f28d51 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -9651,6 +9651,11 @@ __init static void enable_instances(void) if (flag_delim) *flag_delim++ = '\0'; + if (trace_array_find(name)) { + pr_warn("Tracing: Instance %s already exists\n", name); + continue; + } + if (backup) { if (backup_instance_area(backup, &addr, &size) < 0) continue;