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 9B38E5D73C; Mon, 18 Dec 2023 12:45:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="JN+2IGCE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 36411C433C9; Mon, 18 Dec 2023 12:45:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1702903532; bh=uvqxq9ivRICZK7D93QOfg+Z9GhD5LpEsFUd7tOOgJhw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JN+2IGCEMpcCg9B+gVq9YbgmW9+LOcuvYzGOlqhJXgPFBDXWY36J3MWt3Coq2gibB qslou2GodNp/qeKtgxHgdxp3/ojTs0fiWtFF/bsHltx4gcYlQBcYBHWmdT/4XNT9jC Y0sjOhT688t0mT3+5N5Jn8kZ6cujWDN7DxqTqbTXd29ZMRMJgg9Yh7OohJFKc+mnfW ioo9zCiP95U4pNUzqoPPNLzuNzdZt21VhLdo4Yyg2fQYtWEF1TshphCO7Pj0ri2gs4 hayUNqOOnhShii30ewb4H/OhoLDW6UGhxCx9B9YSOVjMhvbi7FqfdQxHBu4WMvC4nO knGkrG6/ACr8Q== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: "Steven Rostedt (Google)" , Mark Rutland , Mathieu Desnoyers , Masami Hiramatsu , Sasha Levin , linux-trace-kernel@vger.kernel.org Subject: [PATCH AUTOSEL 6.1 10/15] tracing: Have large events show up as '[LINE TOO BIG]' instead of nothing Date: Mon, 18 Dec 2023 07:44:57 -0500 Message-ID: <20231218124513.1380056-10-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20231218124513.1380056-1-sashal@kernel.org> References: <20231218124513.1380056-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.1.68 Content-Transfer-Encoding: 8bit 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 d2db4d6f0f2fd..cfab12e266d98 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -4665,7 +4665,11 @@ 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