[for-linus][PATCH 2/3] tracing: Fix enabling multiple events on the kernel command line and bootconfig

[for-linus][PATCH 2/3] tracing: Fix enabling multiple events on the kernel command line and bootconfig

[Steven Rostedt]

From: Andrei-Alexandru Tachici <andrei-alexandru.tachici@oss.qualcomm.com>

Multiple events can be enabled on the kernel command line via a comma
separator. But if the are specified one at a time, then only the last
event is enabled. This is because the event names are saved in a temporary
buffer, and each call by the init cmdline code will reset that buffer.

This also affects names in the boot config file, as it may call the
callback multiple times with an example of:

  kernel.trace_event = ":mod:rproc_qcom_common", ":mod:qrtr", ":mod:qcom_aoss"

Change the cmdline callback function to append a comma and the next value
if the temporary buffer already has content.

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20260302-trace-events-allow-multiple-modules-v1-1-ce4436e37fb8@oss.qualcomm.com
Signed-off-by: Andrei-Alexandru Tachici <andrei-alexandru.tachici@oss.qualcomm.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 kernel/trace/trace_events.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index b7343fdfd7b0..249d1cba72c0 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -4493,7 +4493,11 @@ static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
 
 static __init int setup_trace_event(char *str)
 {
-	strscpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
+	if (bootup_event_buf[0] != '\0')
+		strlcat(bootup_event_buf, ",", COMMAND_LINE_SIZE);
+
+	strlcat(bootup_event_buf, str, COMMAND_LINE_SIZE);
+
 	trace_set_ring_buffer_expanded(NULL);
 	disable_tracing_selftest("running event tracing");
 
-- 
2.51.0

[for-linus][PATCH 3/3] tracing: Fix trace_buf_size= cmdline parameter with sizes >= 2G

[Steven Rostedt]

From: Calvin Owens <calvin@wbinvd.org>

Some of the sizing logic through tracer_alloc_buffers() uses int
internally, causing unexpected behavior if the user passes a value that
does not fit in an int (on my x86 machine, the result is uselessly tiny
buffers).

Fix by plumbing the parameter's real type (unsigned long) through to the
ring buffer allocation functions, which already use unsigned long.

It has always been possible to create larger ring buffers via the sysfs
interface: this only affects the cmdline parameter.

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/bff42a4288aada08bdf74da3f5b67a2c28b761f8.1772852067.git.calvin@wbinvd.org
Fixes: 73c5162aa362 ("tracing: keep ring buffer to minimum size till used")
Signed-off-by: Calvin Owens <calvin@wbinvd.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 kernel/trace/trace.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 1e7c032a72d2..ebd996f8710e 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -9350,7 +9350,7 @@ static void setup_trace_scratch(struct trace_array *tr,
 }
 
 static int
-allocate_trace_buffer(struct trace_array *tr, struct array_buffer *buf, int size)
+allocate_trace_buffer(struct trace_array *tr, struct array_buffer *buf, unsigned long size)
 {
 	enum ring_buffer_flags rb_flags;
 	struct trace_scratch *tscratch;
@@ -9405,7 +9405,7 @@ static void free_trace_buffer(struct array_buffer *buf)
 	}
 }
 
-static int allocate_trace_buffers(struct trace_array *tr, int size)
+static int allocate_trace_buffers(struct trace_array *tr, unsigned long size)
 {
 	int ret;
 
@@ -10769,7 +10769,7 @@ __init static void enable_instances(void)
 
 __init static int tracer_alloc_buffers(void)
 {
-	int ring_buf_size;
+	unsigned long ring_buf_size;
 	int ret = -ENOMEM;
 
 
-- 
2.51.0