Unverified Commit c4df3531 authored by openeuler-ci-bot's avatar openeuler-ci-bot Committed by Gitee
Browse files

!2377 tracing: Backport bugfixes 

Merge Pull Request from: @ci-robot 
 
PR sync from: Zheng Yejian <zhengyejian1@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/UMN7NGAYHWGX24DTB4MLALCKEPKYXWNK/ 
Chen Lin (1):
  ring-buffer: Do not swap cpu_buffer during resize process

Steven Rostedt (Google) (1):
  ring-buffer: Do not attempt to read past "commit"


-- 
2.25.1
 
https://gitee.com/openeuler/kernel/issues/I86Q1D 
 
Link:https://gitee.com/openeuler/kernel/pulls/2377

 

Reviewed-by: default avatarXu Kuohai <xukuohai@huawei.com>
Signed-off-by: default avatarJialin Zhang <zhangjialin11@huawei.com>
parents cfc785ec cd497548

kernel/trace/ring_buffer.c

+18 −1
Original line number Diff line number Diff line
@@ -539,6 +539,7 @@ struct trace_buffer { 
	unsigned			flags;

	int				cpus;

	atomic_t			record_disabled;

	atomic_t			resizing;

	cpumask_var_t			cpumask;



	struct lock_class_key		*reader_lock_key;
@@ -2038,7 +2039,7 @@ int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size, 


	/* prevent another thread from changing buffer sizes */

	mutex_lock(&buffer->mutex);



	atomic_inc(&buffer->resizing);



	if (cpu_id == RING_BUFFER_ALL_CPUS) {

		/*
@@ -2181,6 +2182,7 @@ int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size, 
		atomic_dec(&buffer->record_disabled);

	}



	atomic_dec(&buffer->resizing);

	mutex_unlock(&buffer->mutex);

	return 0;
@@ -2201,6 +2203,7 @@ int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size, 
		}

	}

 out_err_unlock:

	atomic_dec(&buffer->resizing);

	mutex_unlock(&buffer->mutex);

	return err;

}
@@ -2252,6 +2255,11 @@ rb_iter_head_event(struct ring_buffer_iter *iter) 
	 */

	commit = rb_page_commit(iter_head_page);

	smp_rmb();



	/* An event needs to be at least 8 bytes in size */

	if (iter->head > commit - 8)

		goto reset;



	event = __rb_page_index(iter_head_page, iter->head);

	length = rb_event_length(event);
@@ -5237,6 +5245,15 @@ int ring_buffer_swap_cpu(struct trace_buffer *buffer_a, 
	if (local_read(&cpu_buffer_b->committing))

		goto out_dec;



	/*

	 * When resize is in progress, we cannot swap it because

	 * it will mess the state of the cpu buffer.

	 */

	if (atomic_read(&buffer_a->resizing))

		goto out_dec;

	if (atomic_read(&buffer_b->resizing))

		goto out_dec;



	buffer_a->buffers[cpu] = cpu_buffer_b;

	buffer_b->buffers[cpu] = cpu_buffer_a;

kernel/trace/trace.c

+2 −1
Original line number Diff line number Diff line
@@ -1876,9 +1876,10 @@ update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu) 
		 * place on this CPU. We fail to record, but we reset

		 * the max trace buffer (no one writes directly to it)

		 * and flag that it failed.

		 * Another reason is resize is in progress.

		 */

		trace_array_printk_buf(tr->max_buffer.buffer, _THIS_IP_,

			"Failed to swap buffers due to commit in progress\n");

			"Failed to swap buffers due to commit or resize in progress\n");

	}



	WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY);