From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f44.google.com (mail-wm1-f44.google.com [209.85.128.44]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BFF4F3D3327 for ; Thu, 6 Aug 2026 21:53:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.44 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786053183; cv=none; b=IQCe9O1Txss5bYq47BJLgtDScdCaDhXp3tzUlptjJWRWUL9NDa7S8CJ66pSYQNtyXAGO2F91cNQM8lYzyfZj86X8IKz9FwrJOwBXUkC91VMHzonzliGJSOXPfEYn4SoJnFK9cbe+2B/PPqTZgby7pRd2FXBf1G9oQKHx6+7A4E0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786053183; c=relaxed/simple; bh=1XTpm4URt0IkfvvA3Q7ZAK7H3fkNGIUgUKGK+pqmYDc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=b1/Wp74oOmKMTTfbjYaZp0y0v4Bl747LcGkISsmEkXEa4hpyfS1cmXgXbSmueBhpflAke8NtzXIJawkq0W0+KTphNa3WVQBOPw2PFch0/xP2FLtWmMVhTlULp8a12CXq5aiMwSQ6iAyvn99NQlAK8I96AffYW10l6/ku4MPfubA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=E1S9UdAe; arc=none smtp.client-ip=209.85.128.44 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="E1S9UdAe" Received: by mail-wm1-f44.google.com with SMTP id 5b1f17b1804b1-4955de8797cso17664465e9.3 for ; Thu, 06 Aug 2026 14:53:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1786053180; x=1786657980; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=avK/Zi8hIhs1R5+1CNpCZLSMDvwE9dj5Z6g59fOUQxM=; b=E1S9UdAe67KUTyOb4y2ra3lKRN/7u9DaYNyJfY24sNDc0QJCME6RsiXvb8mE05sNoW Z/05YhnM8pne8N1gu4Dh8fwubFDxoYAR+cKJ6/mogLV6+Ci/PgjgzQaqyFZKzqBeqnnY Y1CXzXnCmow2+tjMZsHOc7qPO+e2rGdCN2/8vIcv7TNCeLlIQW9t1Obxup2VOkHjHMF9 5jGWyaGWWNVGZauKLrjcl2fTG2H0A0Q0/8LA+iElAAR17EnBhDSLegCnD34ApWclmRi6 QNqhJvA/Jd4yvxhqXn7VHjq5PTMpOJCFrkUIFgT+R00QjCw7b7mR69aYMvwLlbNq0N1F yIXw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1786053180; x=1786657980; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to:content-type; bh=avK/Zi8hIhs1R5+1CNpCZLSMDvwE9dj5Z6g59fOUQxM=; b=XCc+Z2TrE2Zw7Zz4sIeZf8ZaC8JG0m19yTEUoUhr25veZHhrDstLsxbB5SmzyI89ic l+6CYM3U4htP0/Ik308tg8kpgazRF3TeLGa+FLQLRlMsZcaT9nURL4itr4BVcVwpReSh VTY+A6ZmKwmwc9d3GoDkrV5aQrJS16v4gx4rq34UvbtTppigD/kwuqYkLmm1Md5J5W2i IaKXf1y6rMvZO0OYuJ86/IaGVKGBpEMWh5Y7oXFm4lMF5a773643ZICoXS7+8L8FRdGy EFJRmqCH+RCzq7G32eGNty1vi5wADGxOQTLWcz9bxwlaJB/rH3k3PUAzpGgo2Z4qQy56 Ejmg== X-Forwarded-Encrypted: i=1; AHgh+RrziQHTVckPe0JtkVqwzZSe9pKR4b0U2q2tTIDqrtaK/6af3z29bOqOlNACvE9G5IiJ4vmgjZ1vqsUVnFI=@vger.kernel.org X-Gm-Message-State: AOJu0Ywg90TfzNmDeQ2gNlbcXMKAeio2ejAnnVogO/2VN1JNBGA7XiNd PbSdBI59Zv/j2ZU1MPUsxCyZWEnCezO4qYcorZ5OtH9szUB/bpSN23hq X-Gm-Gg: AR+sD10paYGhRdQeqDL8sSM9wwqV8i7qDGNAZqIjwkn+LFGJEER9lgifeGJMdaMFYBu scbC68ZhpfpTBNmomAI1w+Cc6WmWuYxqVW8BGGqJD0D8R1NSSAZHYBgrAqgR6AJJ/yz+KmQb/CS V8DZfvZQUY63yhqoGqfBFV8ZGH6/z/DNkZJofcHBM4ndgfjVNAMvDFnZeHRuROMbKnuy4ZTVZbt zfrywqyqYzL2uxf7rrmb9YTAHAUrwHvMP82/hLasIXJAhk1j4N1JJtHhBRWZZ2sqDs2eKxoptQ1 pRTFhr/1FQ6k8Ff5Dxzr99VEyVPk6g2JvXrtVh9oqIaE2nqwgS1UXGakSsXD21ZKnNnMr7DNCRF 5oF6F0jNk9UFzaWaew0yv2ZHaBmaOtvclPcS0FYs/Nkuv4X9YSXnqT6Zrv3aVe906pJJB7FQIO4 +FznWdV9RpPSGQ0arzyHru1wZ004QLQp2bA3bBAHCueC7rW0H6MZVdTV1KFS79IW8jim7S9Kp22 9IFE/azJfqFkdD9fuXk9yx5uLgCESY600QTtmOLHJaltZUF X-Received: by 2002:a05:600c:529b:b0:493:a613:56b2 with SMTP id 5b1f17b1804b1-4994e71d3e5mr261220245e9.8.1786053179725; Thu, 06 Aug 2026 14:52:59 -0700 (PDT) Received: from dohko.chello.ie (188-141-5-72.dynamic.upc.ie. [188.141.5.72]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-499541b86f5sm91381405e9.0.2026.08.06.14.52.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 06 Aug 2026 14:52:59 -0700 (PDT) From: David Carlier To: Steven Rostedt Cc: Masami Hiramatsu , Mathieu Desnoyers , linux-trace-kernel@vger.kernel.org, linux-kernel@vger.kernel.org, David Carlier Subject: [PATCH v2] tracing: Report every TP_printk double dereference Date: Thu, 6 Aug 2026 22:52:56 +0100 Message-ID: <20260806215256.1680267-1-devnexen@gmail.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260806174110.11fcd317@gandalf.local.home> References: <20260806174110.11fcd317@gandalf.local.home> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit WARN_ONCE() splats once per call site, so only the first offending event registered is ever reported. The tree currently has six: ice_{rx,tx}_dim_template, two hfi1 txq events, mtu3_ep and edma_log_io. Whichever registers first hides the rest, and each has to be found again on the next boot. Add a pr_warn() next to the WARN_ONCE() so every offender is listed, the same way test_event_printk() already pairs WARN_ON_ONCE() with pr_warn() for unsafe %p* dereferences. The WARN_ONCE() stays so the condition still fails tests and panics under panic_on_warn. Suggested-by: Steven Rostedt Signed-off-by: David Carlier --- kernel/trace/trace_events.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index a8590d2394e3..ce902482ec7c 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -415,6 +415,8 @@ static void test_double_dereference(const char *str, int len, ptr += 5; for (; ptr < end; ptr++) { if (ptr[0] == '-' && ptr[1] == '>') { + pr_warn("TRACE EVENT ERROR: Event %s has double dereference in TP_printk: %.*s\n", + trace_event_name(call), len, str); WARN_ONCE(1, "Event %s has double dereference in TP_printk: %.*s\n", trace_event_name(call), len, str); return; -- 2.55.0