diff options
| -rw-r--r-- | kernel/trace/trace.c | 38 | ||||
| -rw-r--r-- | kernel/trace/trace.h | 6 | ||||
| -rw-r--r-- | kernel/trace/trace_irqsoff.c | 19 | ||||
| -rw-r--r-- | kernel/trace/trace_sched_wakeup.c | 18 |
4 files changed, 65 insertions, 16 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 02debabe9ed..4f1dade5698 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2881,11 +2881,25 @@ static int set_tracer_option(struct tracer *trace, char *cmp, int neg) return -EINVAL; } -static void set_tracer_flags(unsigned int mask, int enabled) +/* Some tracers require overwrite to stay enabled */ +int trace_keep_overwrite(struct tracer *tracer, u32 mask, int set) +{ + if (tracer->enabled && (mask & TRACE_ITER_OVERWRITE) && !set) + return -1; + + return 0; +} + +int set_tracer_flag(unsigned int mask, int enabled) { /* do nothing if flag is already set */ if (!!(trace_flags & mask) == !!enabled) - return; + return 0; + + /* Give the tracer a chance to approve the change */ + if (current_trace->flag_changed) + if (current_trace->flag_changed(current_trace, mask, !!enabled)) + return -EINVAL; if (enabled) trace_flags |= mask; @@ -2904,13 +2918,15 @@ static void set_tracer_flags(unsigned int mask, int enabled) if (mask == TRACE_ITER_PRINTK) trace_printk_start_stop_comm(enabled); + + return 0; } static int trace_set_options(char *option) { char *cmp; int neg = 0; - int ret = 0; + int ret = -ENODEV; int i; cmp = strstrip(option); @@ -2924,7 +2940,7 @@ static int trace_set_options(char *option) for (i = 0; trace_options[i]; i++) { if (strcmp(cmp, trace_options[i]) == 0) { - set_tracer_flags(1 << i, !neg); + ret = set_tracer_flag(1 << i, !neg); break; } } @@ -2943,6 +2959,7 @@ tracing_trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) { char buf[64]; + int ret; if (cnt >= sizeof(buf)) return -EINVAL; @@ -2952,7 +2969,9 @@ tracing_trace_options_write(struct file *filp, const char __user *ubuf, buf[cnt] = 0; - trace_set_options(buf); + ret = trace_set_options(buf); + if (ret < 0) + return ret; *ppos += cnt; @@ -3256,6 +3275,9 @@ static int tracing_set_tracer(const char *buf) goto out; trace_branch_disable(); + + current_trace->enabled = false; + if (current_trace->reset) current_trace->reset(tr); @@ -3300,6 +3322,7 @@ static int tracing_set_tracer(const char *buf) } current_trace = t; + current_trace->enabled = true; trace_branch_enable(tr); out: mutex_unlock(&trace_types_lock); @@ -4788,9 +4811,12 @@ trace_options_core_write(struct file *filp, const char __user *ubuf, size_t cnt, return -EINVAL; mutex_lock(&trace_types_lock); - set_tracer_flags(1 << index, val); + ret = set_tracer_flag(1 << index, val); mutex_unlock(&trace_types_lock); + if (ret < 0) + return ret; + *ppos += cnt; return cnt; diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 57d7e5397d5..2081971367e 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -283,11 +283,15 @@ struct tracer { enum print_line_t (*print_line)(struct trace_iterator *iter); /* If you handled the flag setting, return 0 */ int (*set_flag)(u32 old_flags, u32 bit, int set); + /* Return 0 if OK with change, else return non-zero */ + int (*flag_changed)(struct tracer *tracer, + u32 mask, int set); struct tracer *next; struct tracer_flags *flags; bool print_max; bool use_max_tr; bool allocated_snapshot; + bool enabled; }; @@ -943,6 +947,8 @@ extern const char *__stop___trace_bprintk_fmt[]; void trace_printk_init_buffers(void); void trace_printk_start_comm(void); +int trace_keep_overwrite(struct tracer *tracer, u32 mask, int set); +int set_tracer_flag(unsigned int mask, int enabled); #undef FTRACE_ENTRY #define FTRACE_ENTRY(call, struct_name, id, tstruct, print, filter) \ diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c index 713a2cac488..443b25b43b4 100644 --- a/kernel/trace/trace_irqsoff.c +++ b/kernel/trace/trace_irqsoff.c @@ -32,7 +32,7 @@ enum { static int trace_type __read_mostly; -static int save_lat_flag; +static int save_flags; static void stop_irqsoff_tracer(struct trace_array *tr, int graph); static int start_irqsoff_tracer(struct trace_array *tr, int graph); @@ -558,8 +558,11 @@ static void stop_irqsoff_tracer(struct trace_array *tr, int graph) static void __irqsoff_tracer_init(struct trace_array *tr) { - save_lat_flag = trace_flags & TRACE_ITER_LATENCY_FMT; - trace_flags |= TRACE_ITER_LATENCY_FMT; + save_flags = trace_flags; + + /* non overwrite screws up the latency tracers */ + set_tracer_flag(TRACE_ITER_OVERWRITE, 1); + set_tracer_flag(TRACE_ITER_LATENCY_FMT, 1); tracing_max_latency = 0; irqsoff_trace = tr; @@ -573,10 +576,13 @@ static void __irqsoff_tracer_init(struct trace_array *tr) static void irqsoff_tracer_reset(struct trace_array *tr) { + int lat_flag = save_flags & TRACE_ITER_LATENCY_FMT; + int overwrite_flag = save_flags & TRACE_ITER_OVERWRITE; + stop_irqsoff_tracer(tr, is_graph()); - if (!save_lat_flag) - trace_flags &= ~TRACE_ITER_LATENCY_FMT; + set_tracer_flag(TRACE_ITER_LATENCY_FMT, lat_flag); + set_tracer_flag(TRACE_ITER_OVERWRITE, overwrite_flag); } static void irqsoff_tracer_start(struct trace_array *tr) @@ -609,6 +615,7 @@ static struct tracer irqsoff_tracer __read_mostly = .print_line = irqsoff_print_line, .flags = &tracer_flags, .set_flag = irqsoff_set_flag, + .flag_changed = trace_keep_overwrite, #ifdef CONFIG_FTRACE_SELFTEST .selftest = trace_selftest_startup_irqsoff, #endif @@ -642,6 +649,7 @@ static struct tracer preemptoff_tracer __read_mostly = .print_line = irqsoff_print_line, .flags = &tracer_flags, .set_flag = irqsoff_set_flag, + .flag_changed = trace_keep_overwrite, #ifdef CONFIG_FTRACE_SELFTEST .selftest = trace_selftest_startup_preemptoff, #endif @@ -677,6 +685,7 @@ static struct tracer preemptirqsoff_tracer __read_mostly = .print_line = irqsoff_print_line, .flags = &tracer_flags, .set_flag = irqsoff_set_flag, + .flag_changed = trace_keep_overwrite, #ifdef CONFIG_FTRACE_SELFTEST .selftest = trace_selftest_startup_preemptirqsoff, #endif diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c index 75aa97fbe1a..fde652c9a51 100644 --- a/kernel/trace/trace_sched_wakeup.c +++ b/kernel/trace/trace_sched_wakeup.c @@ -36,7 +36,7 @@ static void __wakeup_reset(struct trace_array *tr); static int wakeup_graph_entry(struct ftrace_graph_ent *trace); static void wakeup_graph_return(struct ftrace_graph_ret *trace); -static int save_lat_flag; +static int save_flags; #define TRACE_DISPLAY_GRAPH 1 @@ -540,8 +540,11 @@ static void stop_wakeup_tracer(struct trace_array *tr) static int __wakeup_tracer_init(struct trace_array *tr) { - save_lat_flag = trace_flags & TRACE_ITER_LATENCY_FMT; - trace_flags |= TRACE_ITER_LATENCY_FMT; + save_flags = trace_flags; + + /* non overwrite screws up the latency tracers */ + set_tracer_flag(TRACE_ITER_OVERWRITE, 1); + set_tracer_flag(TRACE_ITER_LATENCY_FMT, 1); tracing_max_latency = 0; wakeup_trace = tr; @@ -563,12 +566,15 @@ static int wakeup_rt_tracer_init(struct trace_array *tr) static void wakeup_tracer_reset(struct trace_array *tr) { + int lat_flag = save_flags & TRACE_ITER_LATENCY_FMT; + int overwrite_flag = save_flags & TRACE_ITER_OVERWRITE; + stop_wakeup_tracer(tr); /* make sure we put back any tasks we are tracing */ wakeup_reset(tr); - if (!save_lat_flag) - trace_flags &= ~TRACE_ITER_LATENCY_FMT; + set_tracer_flag(TRACE_ITER_LATENCY_FMT, lat_flag); + set_tracer_flag(TRACE_ITER_OVERWRITE, overwrite_flag); } static void wakeup_tracer_start(struct trace_array *tr) @@ -594,6 +600,7 @@ static struct tracer wakeup_tracer __read_mostly = .print_line = wakeup_print_line, .flags = &tracer_flags, .set_flag = wakeup_set_flag, + .flag_changed = trace_keep_overwrite, #ifdef CONFIG_FTRACE_SELFTEST .selftest = trace_selftest_startup_wakeup, #endif @@ -615,6 +622,7 @@ static struct tracer wakeup_rt_tracer __read_mostly = .print_line = wakeup_print_line, .flags = &tracer_flags, .set_flag = wakeup_set_flag, + .flag_changed = trace_keep_overwrite, #ifdef CONFIG_FTRACE_SELFTEST .selftest = trace_selftest_startup_wakeup, #endif |