diff options
Diffstat (limited to 'kernel/trace/ftrace.c')
| -rw-r--r-- | kernel/trace/ftrace.c | 24 |
1 files changed, 16 insertions, 8 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 6d2cb14f9449..fa7ece649fe1 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -381,12 +381,19 @@ static int function_stat_show(struct seq_file *m, void *v) { struct ftrace_profile *rec = v; char str[KSYM_SYMBOL_LEN]; + int ret = 0; #ifdef CONFIG_FUNCTION_GRAPH_TRACER - static DEFINE_MUTEX(mutex); static struct trace_seq s; unsigned long long avg; unsigned long long stddev; #endif + mutex_lock(&ftrace_profile_lock); + + /* we raced with function_profile_reset() */ + if (unlikely(rec->counter == 0)) { + ret = -EBUSY; + goto out; + } kallsyms_lookup(rec->ip, NULL, NULL, NULL, str); seq_printf(m, " %-30.30s %10lu", str, rec->counter); @@ -408,7 +415,6 @@ static int function_stat_show(struct seq_file *m, void *v) do_div(stddev, (rec->counter - 1) * 1000); } - mutex_lock(&mutex); trace_seq_init(&s); trace_print_graph_duration(rec->time, &s); trace_seq_puts(&s, " "); @@ -416,11 +422,12 @@ static int function_stat_show(struct seq_file *m, void *v) trace_seq_puts(&s, " "); trace_print_graph_duration(stddev, &s); trace_print_seq(m, &s); - mutex_unlock(&mutex); #endif seq_putc(m, '\n'); +out: + mutex_unlock(&ftrace_profile_lock); - return 0; + return ret; } static void ftrace_profile_reset(struct ftrace_profile_stat *stat) @@ -1503,6 +1510,8 @@ static void *t_start(struct seq_file *m, loff_t *pos) if (*pos > 0) return t_hash_start(m, pos); iter->flags |= FTRACE_ITER_PRINTALL; + /* reset in case of seek/pread */ + iter->flags &= ~FTRACE_ITER_HASH; return iter; } @@ -1883,7 +1892,6 @@ function_trace_probe_call(unsigned long ip, unsigned long parent_ip) struct hlist_head *hhd; struct hlist_node *n; unsigned long key; - int resched; key = hash_long(ip, FTRACE_HASH_BITS); @@ -1897,12 +1905,12 @@ function_trace_probe_call(unsigned long ip, unsigned long parent_ip) * period. This syncs the hash iteration and freeing of items * on the hash. rcu_read_lock is too dangerous here. */ - resched = ftrace_preempt_disable(); + preempt_disable_notrace(); hlist_for_each_entry_rcu(entry, n, hhd, node) { if (entry->ip == ip) entry->ops->func(ip, parent_ip, &entry->data); } - ftrace_preempt_enable(resched); + preempt_enable_notrace(); } static struct ftrace_ops trace_probe_ops __read_mostly = @@ -2410,7 +2418,7 @@ static const struct file_operations ftrace_filter_fops = { .open = ftrace_filter_open, .read = seq_read, .write = ftrace_filter_write, - .llseek = ftrace_regex_lseek, + .llseek = no_llseek, .release = ftrace_filter_release, }; |