Unverified Commit 5a3aeaf3 authored by openeuler-ci-bot's avatar openeuler-ci-bot Committed by Gitee
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!9264 ring-buffer: Fix a race between readers and resize checks 

Merge Pull Request from: @ci-robot 
 
PR sync from: Zheng Yejian <zhengyejian1@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/4DUUTWTNWSVK4PIZIJAUY2ZEA2YLEXGQ/ 
 
https://gitee.com/src-openeuler/kernel/issues/IA6S8L 
 
Link:https://gitee.com/openeuler/kernel/pulls/9264

 

Reviewed-by: default avatarXu Kuohai <xukuohai@huawei.com>
Reviewed-by: default avatarYe Weihua <yeweihua4@huawei.com>
Signed-off-by: default avatarJialin Zhang <zhangjialin11@huawei.com>
parents 01815e5c 86193567

kernel/trace/ring_buffer.c

+9 −0
Original line number Diff line number Diff line
@@ -1471,6 +1471,11 @@ static int rb_check_bpage(struct ring_buffer_per_cpu *cpu_buffer, 
 *

 * As a safety measure we check to make sure the data pages have not

 * been corrupted.

 *

 * Callers of this function need to guarantee that the list of pages doesn't get

 * modified during the check. In particular, if it's possible that the function

 * is invoked with concurrent readers which can swap in a new reader page then

 * the caller should take cpu_buffer->reader_lock.

 */

static int rb_check_pages(struct ring_buffer_per_cpu *cpu_buffer)

{
@@ -2195,8 +2200,12 @@ int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size, 
		 */

		synchronize_rcu();

		for_each_buffer_cpu(buffer, cpu) {

			unsigned long flags;



			cpu_buffer = buffer->buffers[cpu];

			raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags);

			rb_check_pages(cpu_buffer);

			raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);

		}

		atomic_dec(&buffer->record_disabled);

	}