Merge tag 'trace-v5.9-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt...

Pull tracing fixes from Steven Rostedt:
 "Two tracing fixes:

   - Fix temp buffer accounting that caused a WARNING for
     ftrace_dump_on_opps()

   - Move the recursion check in one of the function callback helpers to
     the beginning of the function, as if the rcu_is_watching() gets
     traced, it will cause a recursive loop that will crash the kernel"

* tag 'trace-v5.9-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  ftrace: Move RCU is watching check after recursion check
  tracing: Fix trace_find_next_entry() accounting of temp buffer size

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 603255f..5414539 100644 (file)
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -6993,16 +6993,14 @@ static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
 {
        int bit;
 
-       if ((op->flags & FTRACE_OPS_FL_RCU) && !rcu_is_watching())
-               return;
-
        bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
        if (bit < 0)
                return;
 
        preempt_disable_notrace();
 
-       op->func(ip, parent_ip, op, regs);
+       if (!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching())
+               op->func(ip, parent_ip, op, regs);
 
        preempt_enable_notrace();
        trace_clear_recursion(bit);

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 2a7c263..d3e5de7 100644 (file)
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3546,13 +3546,15 @@ struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
        if (iter->ent && iter->ent != iter->temp) {
                if ((!iter->temp || iter->temp_size < iter->ent_size) &&
                    !WARN_ON_ONCE(iter->temp == static_temp_buf)) {
-                       kfree(iter->temp);
-                       iter->temp = kmalloc(iter->ent_size, GFP_KERNEL);
-                       if (!iter->temp)
+                       void *temp;
+                       temp = kmalloc(iter->ent_size, GFP_KERNEL);
+                       if (!temp)
                                return NULL;
+                       kfree(iter->temp);
+                       iter->temp = temp;
+                       iter->temp_size = iter->ent_size;
                }
                memcpy(iter->temp, iter->ent, iter->ent_size);
-               iter->temp_size = iter->ent_size;
                iter->ent = iter->temp;
        }
        entry = __find_next_entry(iter, ent_cpu, NULL, ent_ts);