From nobody Wed Apr 1 09:43:21 2026 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 B7A991C84D7 for ; Wed, 1 Apr 2026 00:40:04 +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=1775004004; cv=none; b=Obthiv/bGG2Jmf/pFUZcaeq0RcMtjBwYaRznR/4hNDvpm/9D7HfbYrGb/PYcCnP1XsZS9YUSFH3nC6y6UXwxVLiaosvu6XNr9cAInFBLuEpwPIpR3JnlruO8fY1+HTUgFvLTPaL6ZKcH3+g9EBq2w+/KNjvUTT3eDETQo7mkXXQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775004004; c=relaxed/simple; bh=pM4VEZlMwgxc7H9BmH9Wov5LbqxMmPL1Zyjv967PJIs=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=Mwc/nhgIem56WEob6DeOAYdwDC3QGGUEB0P2Ghu2V5D6OOJ6hmMiF3czcGQsZ1NLMREv6lifTlxveCFNaL0iKzsAD3pcB2AixlVnzZLBSJuYPm/+cE/O0KcwOVtS/ME0tTGiyt24NwhF18Oqg86tfTTrhJxGKn0PcefxuTrmddA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=nIrqh17v; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="nIrqh17v" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 35049C19423; Wed, 1 Apr 2026 00:40:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1775004004; bh=pM4VEZlMwgxc7H9BmH9Wov5LbqxMmPL1Zyjv967PJIs=; h=Date:From:To:Cc:Subject:References:From; b=nIrqh17vBN0B2iI3KffA1N7P4KPoyGajRr6BvIm1tSTY4F48BqkGs+FR3vjjJzm1n /7XqILXK/fOMCZI+4RnUQZ6kq1eDBM+in8mQfgpOWEhgKg6t54ExXom9sZM0SgXWfP PFnI1JbgWa83I18ntWDIAJnas9Hu3gK/v60ZtB4lVnqDQLdplliqMntBVo615ObA1Z mrvFhpHbU5p4m+AWKHNU6w/fAydXAne18/tu0yy0UEbJ8HJiJ0QjIB0Z8/E5JCM+xT 3pNWyXCunJvlGcq+Yvpv1ulrxFmYPTh1weB+XuachtorjENzdghmIN5OpGfMQIV5oq +D0ljLNFoJVYA== Received: from rostedt by gandalf with local (Exim 4.99.1) (envelope-from ) id 1w7jdn-0000000HGet-1tYM; Tue, 31 Mar 2026 20:41:03 -0400 Message-ID: <20260401004103.309943351@kernel.org> User-Agent: quilt/0.69 Date: Tue, 31 Mar 2026 20:40:48 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton , Wesley Atwell Subject: [for-next][PATCH 1/3] tracing: Append repeated boot-time tracing parameters References: <20260401004047.963302108@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Wesley Atwell Some tracing boot parameters already accept delimited value lists, but their __setup() handlers keep only the last instance seen at boot. Make repeated instances append to the same boot-time buffer in the format each parser already consumes. Use a shared trace_append_boot_param() helper for the ftrace filters, trace_options, and kprobe_event boot parameters. This also lets Bootconfig array values work naturally when they expand to repeated param=3Dvalue entries. Before this change, only the last instance from each repeated parameter survived boot. Link: https://patch.msgid.link/20260330181103.1851230-1-atwellwea@gmail.com Signed-off-by: Wesley Atwell Signed-off-by: Steven Rostedt (Google) --- kernel/trace/ftrace.c | 12 ++++++++---- kernel/trace/trace.c | 31 ++++++++++++++++++++++++++++++- kernel/trace/trace.h | 2 ++ kernel/trace/trace_kprobe.c | 3 ++- 4 files changed, 42 insertions(+), 6 deletions(-) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 413310912609..8bd3dd1d549c 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -6841,7 +6841,8 @@ bool ftrace_filter_param __initdata; static int __init set_ftrace_notrace(char *str) { ftrace_filter_param =3D true; - strscpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE); + trace_append_boot_param(ftrace_notrace_buf, str, ',', + FTRACE_FILTER_SIZE); return 1; } __setup("ftrace_notrace=3D", set_ftrace_notrace); @@ -6849,7 +6850,8 @@ __setup("ftrace_notrace=3D", set_ftrace_notrace); static int __init set_ftrace_filter(char *str) { ftrace_filter_param =3D true; - strscpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE); + trace_append_boot_param(ftrace_filter_buf, str, ',', + FTRACE_FILTER_SIZE); return 1; } __setup("ftrace_filter=3D", set_ftrace_filter); @@ -6861,14 +6863,16 @@ static int ftrace_graph_set_hash(struct ftrace_hash= *hash, char *buffer); =20 static int __init set_graph_function(char *str) { - strscpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE); + trace_append_boot_param(ftrace_graph_buf, str, ',', + FTRACE_FILTER_SIZE); return 1; } __setup("ftrace_graph_filter=3D", set_graph_function); =20 static int __init set_graph_notrace_function(char *str) { - strscpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE); + trace_append_boot_param(ftrace_graph_notrace_buf, str, ',', + FTRACE_FILTER_SIZE); return 1; } __setup("ftrace_graph_notrace=3D", set_graph_notrace_function); diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 7b9dd6378849..284f813a61f8 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -221,6 +221,34 @@ static char *default_bootup_tracer; static char boot_instance_info[COMMAND_LINE_SIZE] __initdata; static int boot_instance_index; =20 +/* + * Repeated boot parameters, including Bootconfig array expansions, need + * to stay in the delimiter form that the existing parser consumes. + */ +void __init trace_append_boot_param(char *buf, const char *str, char sep, + int size) +{ + int len, needed, str_len; + + if (!*str) + return; + + len =3D strlen(buf); + str_len =3D strlen(str); + needed =3D len + str_len + 1; + + /* For continuation, account for the separator. */ + if (len) + needed++; + if (needed > size) + return; + + if (len) + buf[len++] =3D sep; + + strscpy(buf + len, str, size - len); +} + static int __init set_cmdline_ftrace(char *str) { strscpy(bootup_tracer_buf, str, MAX_TRACER_SIZE); @@ -290,7 +318,8 @@ static char trace_boot_options_buf[MAX_TRACER_SIZE] __i= nitdata; =20 static int __init set_trace_boot_options(char *str) { - strscpy(trace_boot_options_buf, str, MAX_TRACER_SIZE); + trace_append_boot_param(trace_boot_options_buf, str, ',', + MAX_TRACER_SIZE); return 1; } __setup("trace_options=3D", set_trace_boot_options); diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index a3ea735a9ef6..0904fd356634 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -905,6 +905,8 @@ extern int DYN_FTRACE_TEST_NAME(void); #define DYN_FTRACE_TEST_NAME2 trace_selftest_dynamic_test_func2 extern int DYN_FTRACE_TEST_NAME2(void); =20 +void __init trace_append_boot_param(char *buf, const char *str, + char sep, int size); extern void trace_set_ring_buffer_expanded(struct trace_array *tr); extern bool tracing_selftest_disabled; =20 diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index a5dbb72528e0..e9f1c55aea64 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -31,7 +31,8 @@ static char kprobe_boot_events_buf[COMMAND_LINE_SIZE] __i= nitdata; =20 static int __init set_kprobe_boot_events(char *str) { - strscpy(kprobe_boot_events_buf, str, COMMAND_LINE_SIZE); + trace_append_boot_param(kprobe_boot_events_buf, str, ';', + COMMAND_LINE_SIZE); disable_tracing_selftest("running kprobe events"); =20 return 1; --=20 2.51.0