diff options
Diffstat (limited to 'kernel/trace/trace.c')
| -rw-r--r-- | kernel/trace/trace.c | 35 |
1 files changed, 29 insertions, 6 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 420d49e..b3ae845 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2527,11 +2527,25 @@ 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; @@ -2543,6 +2557,8 @@ static void set_tracer_flags(unsigned int mask, int enabled) if (mask == TRACE_ITER_OVERWRITE) ring_buffer_change_overwrite(global_trace.buffer, enabled); + + return 0; } static ssize_t @@ -2552,7 +2568,7 @@ tracing_trace_options_write(struct file *filp, const char __user *ubuf, char buf[64]; char *cmp; int neg = 0; - int ret = 0; + int ret = -ENODEV; int i; if (cnt >= sizeof(buf)) @@ -2573,7 +2589,7 @@ tracing_trace_options_write(struct file *filp, const char __user *ubuf, 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; } } @@ -2584,7 +2600,7 @@ tracing_trace_options_write(struct file *filp, const char __user *ubuf, mutex_unlock(&trace_types_lock); - if (ret) + if (ret < 0) return ret; *ppos += cnt; @@ -2883,6 +2899,9 @@ static int tracing_set_tracer(const char *buf) goto out; trace_branch_disable(); + + current_trace->enabled = false; + if (current_trace && current_trace->reset) current_trace->reset(tr); if (current_trace && current_trace->use_max_tr) { @@ -2912,6 +2931,7 @@ static int tracing_set_tracer(const char *buf) goto out; } + current_trace->enabled = true; trace_branch_enable(tr); out: mutex_unlock(&trace_types_lock); @@ -4184,9 +4204,12 @@ 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; |