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 DFF801B96D; Thu, 18 Jan 2024 10:54:50 +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=1705575291; cv=none; b=uZILvd9qk5FpA5+aFLMvQJ3FxkIEZXxj2O6sXX/qz3FdfoJUJTcOZ3Gudr0/yd6S+gNxWx8D5WV04RXFqZzBg3dZosNllQ70jC9Jh/gW0IHEe7KlgyMuYKqoxFJOWpXkufycfTH6tZccIpwZFyTCTem1QFw9BS81AG3mSciVu8I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705575291; c=relaxed/simple; bh=BvhZwxs4npaTBRCyQXm02iq2rJ+I818hOfK6JbYWLrs=; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID: X-Mailer:In-Reply-To:References:User-Agent:X-stable: X-Patchwork-Hint:MIME-Version:Content-Transfer-Encoding; b=oxs8x+9LP+BO1E+cIP8tvnyyE7rcFFwTY/vhIdA0fwQeAv1ntoegtMgKnp66Ib7q+o3j+Q8TpGK1ZJZGqXkTaL+JgjFrDzd/0bg/LFmaeI4IFArbPcq50DKskWBl0TfRXqcv8PKdPK/rGe6FplZXMFY0Wt5kOcQKNM2HFcK35sw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=hruQDypO; 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="hruQDypO" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5CD2AC433C7; Thu, 18 Jan 2024 10:54:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1705575290; bh=BvhZwxs4npaTBRCyQXm02iq2rJ+I818hOfK6JbYWLrs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hruQDypOfdrgjJgaEcVn/w0bx4RRpN7NP/LQe59duE5EhaxdtFCdo9RLkMbTeBgby Iq79SmLFvpcn0WVVb1CWWdZuyA7OiDkoQvLGcU9vkWR4LGI1wwRNZbKSpuaOHlBqC4 /TglxwoMkMy1zo9DcQN90R0QtmxdVBf7l4Om2Fr4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Mark Rutland , Mathieu Desnoyers , "Masami Hiramatsu (Google)" , "Steven Rostedt (Google)" , Sasha Levin Subject: [PATCH 6.6 079/150] tracing: Have large events show up as [LINE TOO BIG] instead of nothing Date: Thu, 18 Jan 2024 11:48:21 +0100 Message-ID: <20240118104323.629120307@linuxfoundation.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240118104320.029537060@linuxfoundation.org> References: <20240118104320.029537060@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev 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: Steven Rostedt (Google) [ Upstream commit b55b0a0d7c4aa2dac3579aa7e6802d1f57445096 ] If a large event was added to the ring buffer that is larger than what the trace_seq can handle, it just drops the output: ~# cat /sys/kernel/tracing/trace # tracer: nop # # entries-in-buffer/entries-written: 2/2 #P:8 # # _-----=> irqs-off/BH-disabled # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / _-=> migrate-disable # |||| / delay # TASK-PID CPU# ||||| TIMESTAMP FUNCTION # | | | ||||| | | <...>-859 [001] ..... 141.118951: tracing_mark_write <...>-859 [001] ..... 141.148201: tracing_mark_write: 78901234 Instead, catch this case and add some context: ~# cat /sys/kernel/tracing/trace # tracer: nop # # entries-in-buffer/entries-written: 2/2 #P:8 # # _-----=> irqs-off/BH-disabled # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / _-=> migrate-disable # |||| / delay # TASK-PID CPU# ||||| TIMESTAMP FUNCTION # | | | ||||| | | <...>-852 [001] ..... 121.550551: tracing_mark_write[LINE TOO BIG] <...>-852 [001] ..... 121.550581: tracing_mark_write: 78901234 This now emulates the same output as trace_pipe. Link: https://lore.kernel.org/linux-trace-kernel/20231209171058.78c1a026@gandalf.local.home Cc: Mark Rutland Cc: Mathieu Desnoyers Reviewed-by: Masami Hiramatsu (Google) Signed-off-by: Steven Rostedt (Google) Signed-off-by: Sasha Levin --- kernel/trace/trace.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index a55f7d091355..438c5b64db25 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -4744,7 +4744,11 @@ static int s_show(struct seq_file *m, void *v) iter->leftover = ret; } else { - print_trace_line(iter); + ret = print_trace_line(iter); + if (ret == TRACE_TYPE_PARTIAL_LINE) { + iter->seq.full = 0; + trace_seq_puts(&iter->seq, "[LINE TOO BIG]\n"); + } ret = trace_print_seq(m, &iter->seq); /* * If we overflow the seq_file buffer, then it will -- 2.43.0