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authorSteven Rostedt <rostedt@goodmis.org>2008-09-29 23:02:40 -0400
committerIngo Molnar <mingo@elte.hu>2008-10-14 04:38:56 -0400
commited56829cb3195de499f97fa6108fe9134319bae6 (patch)
treee038bfb9898146dead5a20d2a1ffb44f8fb24676 /kernel
parenta7b1374333407f409cf8df7e623b12490f073c84 (diff)
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: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/ring_buffer.c19
1 files changed, 15 insertions, 4 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 95ca9338cb6c..cfa711374d9a 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -128,6 +128,17 @@ struct buffer_page {
128}; 128};
129 129
130/* 130/*
131 * Also stolen from mm/slob.c. Thanks to Mathieu Desnoyers for pointing
132 * this issue out.
133 */
134static inline void free_buffer_page(struct buffer_page *bpage)
135{
136 reset_page_mapcount(&bpage->page);
137 bpage->page.mapping = NULL;
138 __free_page(&bpage->page);
139}
140
141/*
131 * We need to fit the time_stamp delta into 27 bits. 142 * We need to fit the time_stamp delta into 27 bits.
132 */ 143 */
133static inline int test_time_stamp(u64 delta) 144static inline int test_time_stamp(u64 delta)
@@ -240,7 +251,7 @@ static int rb_allocate_pages(struct ring_buffer_per_cpu *cpu_buffer,
240 free_pages: 251 free_pages:
241 list_for_each_entry_safe(page, tmp, &pages, list) { 252 list_for_each_entry_safe(page, tmp, &pages, list) {
242 list_del_init(&page->list); 253 list_del_init(&page->list);
243 __free_page(&page->page); 254 free_buffer_page(page);
244 } 255 }
245 return -ENOMEM; 256 return -ENOMEM;
246} 257}
@@ -284,7 +295,7 @@ static void rb_free_cpu_buffer(struct ring_buffer_per_cpu *cpu_buffer)
284 295
285 list_for_each_entry_safe(page, tmp, head, list) { 296 list_for_each_entry_safe(page, tmp, head, list) {
286 list_del_init(&page->list); 297 list_del_init(&page->list);
287 __free_page(&page->page); 298 free_buffer_page(page);
288 } 299 }
289 kfree(cpu_buffer); 300 kfree(cpu_buffer);
290} 301}
@@ -393,7 +404,7 @@ rb_remove_pages(struct ring_buffer_per_cpu *cpu_buffer, unsigned nr_pages)
393 p = cpu_buffer->pages.next; 404 p = cpu_buffer->pages.next;
394 page = list_entry(p, struct buffer_page, list); 405 page = list_entry(p, struct buffer_page, list);
395 list_del_init(&page->list); 406 list_del_init(&page->list);
396 __free_page(&page->page); 407 free_buffer_page(page);
397 } 408 }
398 BUG_ON(list_empty(&cpu_buffer->pages)); 409 BUG_ON(list_empty(&cpu_buffer->pages));
399 410
@@ -520,7 +531,7 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size)
520 free_pages: 531 free_pages:
521 list_for_each_entry_safe(page, tmp, &pages, list) { 532 list_for_each_entry_safe(page, tmp, &pages, list) {
522 list_del_init(&page->list); 533 list_del_init(&page->list);
523 __free_page(&page->page); 534 free_buffer_page(page);
524 } 535 }
525 return -ENOMEM; 536 return -ENOMEM;
526} 537}