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. trace_trigger= tokenizes its backing storage in place, so keep a running offset and only parse the newly appended chunk into bootup_triggers[]. This also lets Bootconfig array values work naturally when they expand to repeated param=value entries. Validated by booting with repeated ftrace_filter=, ftrace_notrace=, ftrace_graph_filter=, ftrace_graph_notrace=, trace_options=, kprobe_event=, and trace_trigger= parameters and confirming that the resulting tracefs state preserved every requested entry. Before this change, only the last instance from each repeated parameter survived boot. Signed-off-by: Wesley Atwell <[email protected]> --- v5: - use int sizes in the shared append helper and trace_trigger bookkeeping - keep a single bounded append path that only inserts the separator after the first entry - only advance the trace_trigger buffer offset after a successful append kernel/trace/ftrace.c | 12 ++++++++---- kernel/trace/trace.c | 29 ++++++++++++++++++++++++++++- kernel/trace/trace.h | 2 ++ kernel/trace/trace_events.c | 23 ++++++++++++++++++++--- kernel/trace/trace_kprobe.c | 3 ++- 5 files changed, 60 insertions(+), 9 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 = 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=", set_ftrace_notrace); @@ -6849,7 +6850,8 @@ __setup("ftrace_notrace=", set_ftrace_notrace); static int __init set_ftrace_filter(char *str) { ftrace_filter_param = 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=", set_ftrace_filter); @@ -6861,14 +6863,16 @@ static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer); 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=", set_graph_function); 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=", set_graph_notrace_function); diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index a626211ceb9a..c8cf45dc4152 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -228,6 +228,32 @@ static int boot_instance_index; static char boot_snapshot_info[COMMAND_LINE_SIZE] __initdata; static int boot_snapshot_index; +/* + * 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 = strlen(buf); + str_len = strlen(str); + needed = len + str_len + 1; + if (len) + needed++; + if (needed > size) + return; + + if (len) + buf[len++] = sep; + + strscpy(buf + len, str, size - len); +} + static int __init set_cmdline_ftrace(char *str) { strscpy(bootup_tracer_buf, str, MAX_TRACER_SIZE); @@ -329,7 +355,8 @@ static char trace_boot_options_buf[MAX_TRACER_SIZE] __initdata; 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=", set_trace_boot_options); diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index b8f3804586a0..237a0417de1c 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -863,6 +863,8 @@ extern int DYN_FTRACE_TEST_NAME(void); extern int DYN_FTRACE_TEST_NAME2(void); extern void trace_set_ring_buffer_expanded(struct trace_array *tr); +void __init trace_append_boot_param(char *buf, const char *str, + char sep, int size); extern bool tracing_selftest_disabled; #ifdef CONFIG_FTRACE_STARTUP_TEST diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 249d1cba72c0..7f0bec4622f6 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -3679,20 +3679,37 @@ static struct boot_triggers { } bootup_triggers[MAX_BOOT_TRIGGERS]; static char bootup_trigger_buf[COMMAND_LINE_SIZE]; +static int bootup_trigger_buf_len; static int nr_boot_triggers; static __init int setup_trace_triggers(char *str) { + char *slot; char *trigger; char *buf; int i; - strscpy(bootup_trigger_buf, str, COMMAND_LINE_SIZE); + if (bootup_trigger_buf_len >= COMMAND_LINE_SIZE) + return 1; + + slot = bootup_trigger_buf + bootup_trigger_buf_len; + + /* + * trace_trigger= parsing tokenizes the backing storage in place. + * Copy each repeated parameter into fresh space and only parse that + * newly copied chunk here. + */ + trace_append_boot_param(slot, str, '\0', + COMMAND_LINE_SIZE - bootup_trigger_buf_len); + if (!*slot) + return 1; + + bootup_trigger_buf_len += strlen(slot) + 1; trace_set_ring_buffer_expanded(NULL); disable_tracing_selftest("running event triggers"); - buf = bootup_trigger_buf; - for (i = 0; i < MAX_BOOT_TRIGGERS; i++) { + buf = slot; + for (i = nr_boot_triggers; i < MAX_BOOT_TRIGGERS; i++) { trigger = strsep(&buf, ","); if (!trigger) break; 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] __initdata; 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"); return 1; -- 2.43.0
