Commit aa5ff935 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

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

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
parents 60e72093 b40341fa

kernel/trace/ftrace.c

+2 −4
Original line number Diff line number Diff line
@@ -6993,15 +6993,13 @@ 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();



	if (!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching())

		op->func(ip, parent_ip, op, regs);



	preempt_enable_notrace();

kernel/trace/trace.c

+6 −4
Original line number Diff line number Diff line
@@ -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);

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