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ring_buffer: reset buffer page when freeing

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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: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Steven Rostedt 2008-09-29 23:02:40 -04:00 • committed by Ingo Molnar
parent a7b1374333
commit ed56829cb3
1 changed files with 15 additions and 4 deletions
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19
kernel/trace/ring_buffer.c
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@ -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. * 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: free_pages:
list_for_each_entry_safe(page, tmp, &pages, list) { list_for_each_entry_safe(page, tmp, &pages, list) {
list_del_init(&page->list); list_del_init(&page->list);
__free_page(&page->page); free_buffer_page(page);
} }
return -ENOMEM; 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_for_each_entry_safe(page, tmp, head, list) {
list_del_init(&page->list); list_del_init(&page->list);
__free_page(&page->page); free_buffer_page(page);
} }
kfree(cpu_buffer); 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; p = cpu_buffer->pages.next;
page = list_entry(p, struct buffer_page, list); page = list_entry(p, struct buffer_page, list);
list_del_init(&page->list); list_del_init(&page->list);
__free_page(&page->page); free_buffer_page(page);
} }
BUG_ON(list_empty(&cpu_buffer->pages)); BUG_ON(list_empty(&cpu_buffer->pages));
@ -520,7 +531,7 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size)
free_pages: free_pages:
list_for_each_entry_safe(page, tmp, &pages, list) { list_for_each_entry_safe(page, tmp, &pages, list) {
list_del_init(&page->list); list_del_init(&page->list);
__free_page(&page->page); free_buffer_page(page);
} }
return -ENOMEM; return -ENOMEM;
} }