From f39e239102837c603ebf3264eaa4a9385323c5c6 Mon Sep 17 00:00:00 2001 From: "Lee, Chun-Yi" Date: Fri, 16 Jun 2017 16:26:43 +0800 Subject: tracepoints: Fix the descriptions of tracepoint_probe_register{_prio} The description of tracepoint_probe_register duplicates with tracepoint_probe_register_prio. This patch cleans up the descriptions. Link: http://lkml.kernel.org/r/20170616082643.7311-1-jlee@suse.com Signed-off-by: "Lee, Chun-Yi" Signed-off-by: Steven Rostedt (VMware) --- kernel/tracepoint.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c index 1e37da2..6dc6356 100644 --- a/kernel/tracepoint.c +++ b/kernel/tracepoint.c @@ -257,7 +257,7 @@ static int tracepoint_remove_func(struct tracepoint *tp, } /** - * tracepoint_probe_register - Connect a probe to a tracepoint + * tracepoint_probe_register_prio - Connect a probe to a tracepoint with priority * @tp: tracepoint * @probe: probe handler * @data: tracepoint data @@ -290,7 +290,6 @@ EXPORT_SYMBOL_GPL(tracepoint_probe_register_prio); * @tp: tracepoint * @probe: probe handler * @data: tracepoint data - * @prio: priority of this function over other registered functions * * Returns 0 if ok, error value on error. * Note: if @tp is within a module, the caller is responsible for -- cgit v1.1 From c94e45bc38ae484ee989e6e3b2496a52776da9e4 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Mon, 7 May 2018 16:02:14 -0400 Subject: tracing: Do not reference event data in post call triggers Trace event triggers can be called before or after the event has been committed. If it has been called after the commit, there's a possibility that the event no longer exists. Currently, the two post callers is the trigger to disable tracing (traceoff) and the one that will record a stack dump (stacktrace). Neither of them reference the trace event entry record, as that would lead to a race condition that could pass in corrupted data. To prevent any other users of the post data triggers from using the trace event record, pass in NULL to the post call trigger functions for the event record, as they should never need to use them in the first place. This does not fix any bug, but prevents bugs from happening by new post call trigger users. Reviewed-by: Masami Hiramatsu Reviewed-by: Namhyung Kim Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace.h | 4 ++-- kernel/trace/trace_events_trigger.c | 6 ++---- 2 files changed, 4 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 507954b..6bfc246 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -1334,7 +1334,7 @@ event_trigger_unlock_commit(struct trace_event_file *file, trace_buffer_unlock_commit(file->tr, buffer, event, irq_flags, pc); if (tt) - event_triggers_post_call(file, tt, entry, event); + event_triggers_post_call(file, tt); } /** @@ -1367,7 +1367,7 @@ event_trigger_unlock_commit_regs(struct trace_event_file *file, irq_flags, pc, regs); if (tt) - event_triggers_post_call(file, tt, entry, event); + event_triggers_post_call(file, tt); } #define FILTER_PRED_INVALID ((unsigned short)-1) diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c index 8b5bdcf..d182496 100644 --- a/kernel/trace/trace_events_trigger.c +++ b/kernel/trace/trace_events_trigger.c @@ -97,7 +97,6 @@ EXPORT_SYMBOL_GPL(event_triggers_call); * event_triggers_post_call - Call 'post_triggers' for a trace event * @file: The trace_event_file associated with the event * @tt: enum event_trigger_type containing a set bit for each trigger to invoke - * @rec: The trace entry for the event * * For each trigger associated with an event, invoke the trigger * function registered with the associated trigger command, if the @@ -108,8 +107,7 @@ EXPORT_SYMBOL_GPL(event_triggers_call); */ void event_triggers_post_call(struct trace_event_file *file, - enum event_trigger_type tt, - void *rec, struct ring_buffer_event *event) + enum event_trigger_type tt) { struct event_trigger_data *data; @@ -117,7 +115,7 @@ event_triggers_post_call(struct trace_event_file *file, if (data->paused) continue; if (data->cmd_ops->trigger_type & tt) - data->ops->func(data, rec, event); + data->ops->func(data, NULL, NULL); } } EXPORT_SYMBOL_GPL(event_triggers_post_call); -- cgit v1.1 From 3c96529c0739959e2aa235d44e47f5c68c1e40de Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Tue, 8 May 2018 15:06:38 -0400 Subject: tracing: Add __find_event_file() to find event files without restrictions By adding the function __find_event_file() that can search for files without restrictions, such as if the event associated with the file has a reg function, or if it has the "ignore" flag set, the files that are associated to ftrace internal events (like trace_marker and function events) can be found and used. find_event_file() still returns a "filtered" file, as most callers need a valid trace event file. One created by the trace_events.h macros and not one created for parsing ftrace specific events. Reviewed-by: Namhyung Kim Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace.h | 3 +++ kernel/trace/trace_events.c | 22 +++++++++++++++++----- 2 files changed, 20 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 6bfc246..07c4396 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -1454,6 +1454,9 @@ extern void trace_event_enable_tgid_record(bool enable); extern int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr); extern int event_trace_del_tracer(struct trace_array *tr); +extern struct trace_event_file *__find_event_file(struct trace_array *tr, + const char *system, + const char *event); extern struct trace_event_file *find_event_file(struct trace_array *tr, const char *system, const char *event); diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 05c7172..caf7635 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -2473,8 +2473,9 @@ __trace_add_event_dirs(struct trace_array *tr) } } +/* Returns any file that matches the system and event */ struct trace_event_file * -find_event_file(struct trace_array *tr, const char *system, const char *event) +__find_event_file(struct trace_array *tr, const char *system, const char *event) { struct trace_event_file *file; struct trace_event_call *call; @@ -2485,10 +2486,7 @@ find_event_file(struct trace_array *tr, const char *system, const char *event) call = file->event_call; name = trace_event_name(call); - if (!name || !call->class || !call->class->reg) - continue; - - if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE) + if (!name || !call->class) continue; if (strcmp(event, name) == 0 && @@ -2498,6 +2496,20 @@ find_event_file(struct trace_array *tr, const char *system, const char *event) return NULL; } +/* Returns valid trace event files that match system and event */ +struct trace_event_file * +find_event_file(struct trace_array *tr, const char *system, const char *event) +{ + struct trace_event_file *file; + + file = __find_event_file(tr, system, event); + if (!file || !file->event_call->class->reg || + file->event_call->flags & TRACE_EVENT_FL_IGNORE_ENABLE) + return NULL; + + return file; +} + #ifdef CONFIG_DYNAMIC_FTRACE /* Avoid typos */ -- cgit v1.1 From 58b9254757e026102a68cb44a0a15ba63787d0c0 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Tue, 8 May 2018 15:09:27 -0400 Subject: tracing: Have event_trace_init() called by trace_init_tracefs() Instead of having both trace_init_tracefs() and event_trace_init() be called by fs_initcall() routines, have event_trace_init() called directly by trace_init_tracefs(). This will guarantee order of how the events are created with respect to the rest of the ftrace infrastructure. This is needed to be able to assoctiate event files with ftrace internal events, such as the trace_marker. Reviewed-by: Namhyung Kim Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace.c | 2 ++ kernel/trace/trace.h | 1 + kernel/trace/trace_events.c | 4 +--- 3 files changed, 4 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index bcd9303..d5000cb 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -8111,6 +8111,8 @@ static __init int tracer_init_tracefs(void) if (IS_ERR(d_tracer)) return 0; + event_trace_init(); + init_tracer_tracefs(&global_trace, d_tracer); ftrace_init_tracefs_toplevel(&global_trace, d_tracer); diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 07c4396..d0319cb 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -1451,6 +1451,7 @@ trace_find_event_field(struct trace_event_call *call, char *name); extern void trace_event_enable_cmd_record(bool enable); extern void trace_event_enable_tgid_record(bool enable); +extern int event_trace_init(void); extern int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr); extern int event_trace_del_tracer(struct trace_array *tr); diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index caf7635..5b64790 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -3144,7 +3144,7 @@ static __init int event_trace_enable_again(void) early_initcall(event_trace_enable_again); -static __init int event_trace_init(void) +__init int event_trace_init(void) { struct trace_array *tr; struct dentry *d_tracer; @@ -3189,8 +3189,6 @@ void __init trace_event_init(void) event_trace_enable(); } -fs_initcall(event_trace_init); - #ifdef CONFIG_FTRACE_STARTUP_TEST static DEFINE_SPINLOCK(test_spinlock); -- cgit v1.1 From af3dcb53bd77ce83c50e5579db148461aca179e1 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Wed, 9 May 2018 09:24:00 -0400 Subject: tracing: Add brackets in ftrace event dynamic arrays The dynamic arrays defined for ftrace internal events, such as the buf field for trace_marker (ftrace/print) did not have brackets which makes the filter code not accept it as a string. This is not currently an issues because the filter code doesn't do anything for these events, but they will in the future, and this needs to be fixed for when it does. Reviewed-by: Namhyung Kim Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_export.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/trace/trace_export.c b/kernel/trace/trace_export.c index 548e62e..d842f1e 100644 --- a/kernel/trace/trace_export.c +++ b/kernel/trace/trace_export.c @@ -117,7 +117,7 @@ static void __always_unused ____ftrace_check_##name(void) \ #undef __dynamic_array #define __dynamic_array(type, item) \ - ret = trace_define_field(event_call, #type, #item, \ + ret = trace_define_field(event_call, #type "[]", #item, \ offsetof(typeof(field), item), \ 0, is_signed_type(type), filter_type);\ if (ret) \ -- cgit v1.1 From 5d948c86bb332cd143f4b2dc21d949baf38e29aa Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Wed, 9 May 2018 09:48:41 -0400 Subject: tracing: Do not show filter file for ftrace internal events The filter file in the ftrace internal events, like in /sys/kernel/tracing/events/ftrace/function/filter is not attached to any functionality. Do not create them as they are meaningless. In the future, if an ftrace internal event gets filter functionality, then it will need to create it directly. Reviewed-by: Namhyung Kim Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_events.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 5b64790..14ff4ff 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -2007,16 +2007,18 @@ event_create_dir(struct dentry *parent, struct trace_event_file *file) return -1; } } - trace_create_file("filter", 0644, file->dir, file, - &ftrace_event_filter_fops); /* * Only event directories that can be enabled should have - * triggers. + * triggers or filters. */ - if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)) + if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)) { + trace_create_file("filter", 0644, file->dir, file, + &ftrace_event_filter_fops); + trace_create_file("trigger", 0644, file->dir, file, &event_trigger_fops); + } #ifdef CONFIG_HIST_TRIGGERS trace_create_file("hist", 0444, file->dir, file, -- cgit v1.1 From 3dd8095368475a9538895ce757b63dd311e58fe8 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Wed, 9 May 2018 14:17:48 -0400 Subject: tracing: Add trigger file for trace_markers tracefs/ftrace/print Allow writing to the trace_markers file initiate triggers defined in tracefs/ftrace/print/trigger file. This will allow of user space to trigger the same type of triggers (including histograms) that the trace events use. Had to create a ftrace_event_register() function that will become the trace_marker print event's reg() function. This is required because of how triggers are enabled: event_trigger_write() { event_trigger_regex_write() { trigger_process_regex() { for p in trigger_commands { p->func(); /* trigger_snapshot_cmd->func */ event_trigger_callback() { cmd_ops->reg() /* register_trigger() */ { trace_event_trigger_enable_disable() { trace_event_enable_disable() { call->class->reg(); Without the reg() function, the trigger code will call a NULL pointer and crash the system. Cc: Tom Zanussi Cc: Clark Williams Cc: Karim Yaghmour Cc: Brendan Gregg Suggested-by: Joel Fernandes Reviewed-by: Namhyung Kim Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace.c | 17 +++++++++++++++++ kernel/trace/trace.h | 1 + kernel/trace/trace_entries.h | 6 ++++-- kernel/trace/trace_export.c | 7 +++++++ 4 files changed, 29 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index d5000cb..e69820f 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -6074,6 +6074,7 @@ tracing_mark_write(struct file *filp, const char __user *ubuf, { struct trace_array *tr = filp->private_data; struct ring_buffer_event *event; + enum event_trigger_type tt = ETT_NONE; struct ring_buffer *buffer; struct print_entry *entry; unsigned long irq_flags; @@ -6122,6 +6123,12 @@ tracing_mark_write(struct file *filp, const char __user *ubuf, written = cnt; len = cnt; + if (tr->trace_marker_file && !list_empty(&tr->trace_marker_file->triggers)) { + /* do not add \n before testing triggers, but add \0 */ + entry->buf[cnt] = '\0'; + tt = event_triggers_call(tr->trace_marker_file, entry, event); + } + if (entry->buf[cnt - 1] != '\n') { entry->buf[cnt] = '\n'; entry->buf[cnt + 1] = '\0'; @@ -6130,6 +6137,9 @@ tracing_mark_write(struct file *filp, const char __user *ubuf, __buffer_unlock_commit(buffer, event); + if (tt) + event_triggers_post_call(tr->trace_marker_file, tt); + if (written > 0) *fpos += written; @@ -7896,6 +7906,7 @@ static __init void create_trace_instances(struct dentry *d_tracer) static void init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer) { + struct trace_event_file *file; int cpu; trace_create_file("available_tracers", 0444, d_tracer, @@ -7928,6 +7939,12 @@ init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer) trace_create_file("trace_marker", 0220, d_tracer, tr, &tracing_mark_fops); + file = __find_event_file(tr, "ftrace", "print"); + if (file && file->dir) + trace_create_file("trigger", 0644, file->dir, file, + &event_trigger_fops); + tr->trace_marker_file = file; + trace_create_file("trace_marker_raw", 0220, d_tracer, tr, &tracing_mark_raw_fops); diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index d0319cb..630c5a2 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -259,6 +259,7 @@ struct trace_array { struct trace_options *topts; struct list_head systems; struct list_head events; + struct trace_event_file *trace_marker_file; cpumask_var_t tracing_cpumask; /* only trace on set CPUs */ int ref; #ifdef CONFIG_FUNCTION_TRACER diff --git a/kernel/trace/trace_entries.h b/kernel/trace/trace_entries.h index e3a658b..1d67464 100644 --- a/kernel/trace/trace_entries.h +++ b/kernel/trace/trace_entries.h @@ -230,7 +230,7 @@ FTRACE_ENTRY(bprint, bprint_entry, FILTER_OTHER ); -FTRACE_ENTRY(print, print_entry, +FTRACE_ENTRY_REG(print, print_entry, TRACE_PRINT, @@ -242,7 +242,9 @@ FTRACE_ENTRY(print, print_entry, F_printk("%ps: %s", (void *)__entry->ip, __entry->buf), - FILTER_OTHER + FILTER_OTHER, + + ftrace_event_register ); FTRACE_ENTRY(raw_data, raw_data_entry, diff --git a/kernel/trace/trace_export.c b/kernel/trace/trace_export.c index d842f1e..45630a7 100644 --- a/kernel/trace/trace_export.c +++ b/kernel/trace/trace_export.c @@ -14,6 +14,13 @@ #include "trace_output.h" +/* Stub function for events with triggers */ +static int ftrace_event_register(struct trace_event_call *call, + enum trace_reg type, void *data) +{ + return 0; +} + #undef TRACE_SYSTEM #define TRACE_SYSTEM ftrace -- cgit v1.1 From 10f20e9f9da943426382da3d4947ea46fa1db492 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Wed, 9 May 2018 14:22:06 -0400 Subject: tracing: Have zero size length in filter logic be full string As strings in trace events may not have a nul terminating character, the filter string compares use the defined string length for the field for the compares. The trace_marker records data slightly different than do normal events. It's size is zero, meaning that the string is the rest of the array, and that the string also ends with '\0'. If the size is zero, assume that the string is nul terminated and read the string in question as is. Reviewed-by: Namhyung Kim Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_events_filter.c | 23 ++++++++++++----------- 1 file changed, 12 insertions(+), 11 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index 7d306b7..0171407 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -750,31 +750,32 @@ static int filter_pred_none(struct filter_pred *pred, void *event) * * Note: * - @str might not be NULL-terminated if it's of type DYN_STRING - * or STATIC_STRING + * or STATIC_STRING, unless @len is zero. */ static int regex_match_full(char *str, struct regex *r, int len) { - if (strncmp(str, r->pattern, len) == 0) - return 1; - return 0; + /* len of zero means str is dynamic and ends with '\0' */ + if (!len) + return strcmp(str, r->pattern) == 0; + + return strncmp(str, r->pattern, len) == 0; } static int regex_match_front(char *str, struct regex *r, int len) { - if (len < r->len) + if (len && len < r->len) return 0; - if (strncmp(str, r->pattern, r->len) == 0) - return 1; - return 0; + return strncmp(str, r->pattern, r->len) == 0; } static int regex_match_middle(char *str, struct regex *r, int len) { - if (strnstr(str, r->pattern, len)) - return 1; - return 0; + if (!len) + return strstr(str, r->pattern) != NULL; + + return strnstr(str, r->pattern, len) != NULL; } static int regex_match_end(char *str, struct regex *r, int len) -- cgit v1.1 From 3be4c1e52aa5a917aacb1c3829c2d89096b30230 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Thu, 10 May 2018 12:42:10 -0400 Subject: tracing: Allow histogram triggers to access ftrace internal events Now that trace_marker can have triggers, including a histogram triggers, the onmatch() and onmax() access the trace event. To do so, the search routine to find the event file needs to use the raw __find_event_file() that does not filter out ftrace events. Reviewed-by: Namhyung Kim Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_events_hist.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index b9061ed..046c716 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -2865,7 +2865,7 @@ static struct trace_event_file *event_file(struct trace_array *tr, { struct trace_event_file *file; - file = find_event_file(tr, system, event_name); + file = __find_event_file(tr, system, event_name); if (!file) return ERR_PTR(-EINVAL); -- cgit v1.1 From 6167c205ca9c21c82f19978295d99fb60efcf98b Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Wed, 16 May 2018 11:17:06 -0400 Subject: ring-buffer: Fix a bunch of typos in comments An anonymous source sent me a bunch of typo fixes in the comments of ring_buffer.c file. That source did not want to be associated to this patch because they don't want to be known as "one of those" commiters (you know who you are!). They gave me permission to sign this off in my own name. Suggested-by: One-of-those-commiters@YouKnowWhoYouAre.org Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/ring_buffer.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index c9cb976..6a46af2 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -809,7 +809,7 @@ EXPORT_SYMBOL_GPL(ring_buffer_normalize_time_stamp); * * You can see, it is legitimate for the previous pointer of * the head (or any page) not to point back to itself. But only - * temporarially. + * temporarily. */ #define RB_PAGE_NORMAL 0UL @@ -906,7 +906,7 @@ static void rb_list_head_clear(struct list_head *list) } /* - * rb_head_page_dactivate - clears head page ptr (for free list) + * rb_head_page_deactivate - clears head page ptr (for free list) */ static void rb_head_page_deactivate(struct ring_buffer_per_cpu *cpu_buffer) @@ -1780,7 +1780,7 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size, put_online_cpus(); } else { - /* Make sure this CPU has been intitialized */ + /* Make sure this CPU has been initialized */ if (!cpumask_test_cpu(cpu_id, buffer->cpumask)) goto out; @@ -2325,7 +2325,7 @@ rb_update_event(struct ring_buffer_per_cpu *cpu_buffer, /* * If we need to add a timestamp, then we - * add it to the start of the resevered space. + * add it to the start of the reserved space. */ if (unlikely(info->add_timestamp)) { bool abs = ring_buffer_time_stamp_abs(cpu_buffer->buffer); @@ -2681,7 +2681,7 @@ trace_recursive_unlock(struct ring_buffer_per_cpu *cpu_buffer) * ring_buffer_nest_start - Allow to trace while nested * @buffer: The ring buffer to modify * - * The ring buffer has a safty mechanism to prevent recursion. + * The ring buffer has a safety mechanism to prevent recursion. * But there may be a case where a trace needs to be done while * tracing something else. In this case, calling this function * will allow this function to nest within a currently active @@ -2699,7 +2699,7 @@ void ring_buffer_nest_start(struct ring_buffer *buffer) preempt_disable_notrace(); cpu = raw_smp_processor_id(); cpu_buffer = buffer->buffers[cpu]; - /* This is the shift value for the above recusive locking */ + /* This is the shift value for the above recursive locking */ cpu_buffer->nest += NESTED_BITS; } @@ -2718,7 +2718,7 @@ void ring_buffer_nest_end(struct ring_buffer *buffer) /* disabled by ring_buffer_nest_start() */ cpu = raw_smp_processor_id(); cpu_buffer = buffer->buffers[cpu]; - /* This is the shift value for the above recusive locking */ + /* This is the shift value for the above recursive locking */ cpu_buffer->nest -= NESTED_BITS; preempt_enable_notrace(); } @@ -2907,7 +2907,7 @@ rb_reserve_next_event(struct ring_buffer *buffer, * @buffer: the ring buffer to reserve from * @length: the length of the data to reserve (excluding event header) * - * Returns a reseverd event on the ring buffer to copy directly to. + * Returns a reserved event on the ring buffer to copy directly to. * The user of this interface will need to get the body to write into * and can use the ring_buffer_event_data() interface. * @@ -3009,7 +3009,7 @@ rb_decrement_entry(struct ring_buffer_per_cpu *cpu_buffer, * This function lets the user discard an event in the ring buffer * and then that event will not be read later. * - * This function only works if it is called before the the item has been + * This function only works if it is called before the item has been * committed. It will try to free the event from the ring buffer * if another event has not been added behind it. * @@ -4127,7 +4127,7 @@ EXPORT_SYMBOL_GPL(ring_buffer_consume); * through the buffer. Memory is allocated, buffer recording * is disabled, and the iterator pointer is returned to the caller. * - * Disabling buffer recordng prevents the reading from being + * Disabling buffer recording prevents the reading from being * corrupted. This is not a consuming read, so a producer is not * expected. * -- cgit v1.1 From 591a033dc17ff6f684b6b6d1d7426e22d178194f Mon Sep 17 00:00:00 2001 From: Yisheng Xie Date: Thu, 17 May 2018 16:36:03 +0800 Subject: tracing: Use match_string() instead of open coding it in trace_set_options() match_string() returns the index of an array for a matching string, which can be used to simplify the code. Link: http://lkml.kernel.org/r/1526546163-4609-1-git-send-email-xieyisheng1@huawei.com Reviewed-by: Andy Shevchenko Signed-off-by: Yisheng Xie Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace.c | 15 +++++---------- 1 file changed, 5 insertions(+), 10 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index e69820f..108ce3e 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -4395,8 +4395,7 @@ static int trace_set_options(struct trace_array *tr, char *option) { char *cmp; int neg = 0; - int ret = -ENODEV; - int i; + int ret; size_t orig_len = strlen(option); cmp = strstrip(option); @@ -4408,16 +4407,12 @@ static int trace_set_options(struct trace_array *tr, char *option) mutex_lock(&trace_types_lock); - for (i = 0; trace_options[i]; i++) { - if (strcmp(cmp, trace_options[i]) == 0) { - ret = set_tracer_flag(tr, 1 << i, !neg); - break; - } - } - + ret = match_string(trace_options, -1, cmp); /* If no option could be set, test the specific tracer options */ - if (!trace_options[i]) + if (ret < 0) ret = set_tracer_option(tr, cmp, neg); + else + ret = set_tracer_flag(tr, 1 << ret, !neg); mutex_unlock(&trace_types_lock); -- cgit v1.1