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| author | Steven Rostedt <rostedt@goodmis.org> | 2008-09-29 23:02:39 -0400 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-10-14 10:38:55 +0200 |
| commit | a7b1374333407f409cf8df7e623b12490f073c84 (patch) | |
| tree | ecd83a07e17b6659896010adc7ceaa56eb08d12b | |
| parent | 7a8e76a3829f1067b70f715771ff88baf2fbf3c3 (diff) | |
| download | linux-a7b1374333407f409cf8df7e623b12490f073c84.tar.gz linux-a7b1374333407f409cf8df7e623b12490f073c84.tar.bz2 linux-a7b1374333407f409cf8df7e623b12490f073c84.zip | |
ring_buffer: add paranoid check for buffer page
If for some strange reason the buffer_page gets bigger, or the page struct
gets smaller, I want to know this ASAP. The best way is to not let the
kernel compile.
This patch adds code to test the size of the struct buffer_page against the
page struct and will cause compile issues if the buffer_page ever gets bigger
than the page struct.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| -rw-r--r-- | kernel/trace/ring_buffer.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 830a2930dd91..95ca9338cb6c 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -289,6 +289,12 @@ static void rb_free_cpu_buffer(struct ring_buffer_per_cpu *cpu_buffer) kfree(cpu_buffer); } +/* + * Causes compile errors if the struct buffer_page gets bigger + * than the struct page. + */ +extern int ring_buffer_page_too_big(void); + /** * ring_buffer_alloc - allocate a new ring_buffer * @size: the size in bytes that is needed. @@ -305,6 +311,11 @@ struct ring_buffer *ring_buffer_alloc(unsigned long size, unsigned flags) int bsize; int cpu; + /* Paranoid! Optimizes out when all is well */ + if (sizeof(struct buffer_page) > sizeof(struct page)) + ring_buffer_page_too_big(); + + /* keep it in its own cache line */ buffer = kzalloc(ALIGN(sizeof(*buffer), cache_line_size()), GFP_KERNEL); |