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Commit ed56829c authored by Steven Rostedt's avatar Steven Rostedt Committed by Ingo Molnar
Browse files

ring_buffer: reset buffer page when freeing 



Mathieu Desnoyers pointed out that the freeing of the page frame needs
to be reset otherwise we might trigger BUG_ON in the page free code.

Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent a7b13743

kernel/trace/ring_buffer.c

+15 −4
Original line number Diff line number Diff line
@@ -127,6 +127,17 @@ struct buffer_page { 
	};

};



/*

 * Also stolen from mm/slob.c. Thanks to Mathieu Desnoyers for pointing

 * this issue out.

 */

static inline void free_buffer_page(struct buffer_page *bpage)

{

	reset_page_mapcount(&bpage->page);

	bpage->page.mapping = NULL;

	__free_page(&bpage->page);

}



/*

 * We need to fit the time_stamp delta into 27 bits.

 */
@@ -240,7 +251,7 @@ static int rb_allocate_pages(struct ring_buffer_per_cpu *cpu_buffer, 
 free_pages:

	list_for_each_entry_safe(page, tmp, &pages, list) {

		list_del_init(&page->list);

		__free_page(&page->page);

		free_buffer_page(page);

	}

	return -ENOMEM;

}
@@ -284,7 +295,7 @@ static void rb_free_cpu_buffer(struct ring_buffer_per_cpu *cpu_buffer) 


	list_for_each_entry_safe(page, tmp, head, list) {

		list_del_init(&page->list);

		__free_page(&page->page);

		free_buffer_page(page);

	}

	kfree(cpu_buffer);

}
@@ -393,7 +404,7 @@ rb_remove_pages(struct ring_buffer_per_cpu *cpu_buffer, unsigned nr_pages) 
		p = cpu_buffer->pages.next;

		page = list_entry(p, struct buffer_page, list);

		list_del_init(&page->list);

		__free_page(&page->page);

		free_buffer_page(page);

	}

	BUG_ON(list_empty(&cpu_buffer->pages));
@@ -520,7 +531,7 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size) 
 free_pages:

	list_for_each_entry_safe(page, tmp, &pages, list) {

		list_del_init(&page->list);

		__free_page(&page->page);

		free_buffer_page(page);

	}

	return -ENOMEM;

}