diff options
| author | Lai Jiangshan <laijs@cn.fujitsu.com> | 2009-01-12 11:06:18 +0800 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-01-21 15:21:30 +0100 |
| commit | 551b4048b3d4acf15aff9fe4aed89b892c135b02 (patch) | |
| tree | 5d8abe8ac236420a36164c24f98c840e89247e02 /kernel | |
| parent | 00f57f545afa422db3003b0d0b30a30f8de7ecb2 (diff) | |
| download | linux-551b4048b3d4acf15aff9fe4aed89b892c135b02.tar.bz2 | |
ring_buffer: reset write when reserve buffer fail
Impact: reset struct buffer_page.write when interrupt storm
if struct buffer_page.write is not reset, any succedent committing
will corrupted ring_buffer:
static inline void
rb_set_commit_to_write(struct ring_buffer_per_cpu *cpu_buffer)
{
......
cpu_buffer->commit_page->commit =
cpu_buffer->commit_page->write;
......
}
when "if (RB_WARN_ON(cpu_buffer, next_page == reader_page))", ring_buffer
is disabled, but some reserved buffers may haven't been committed.
we need reset struct buffer_page.write.
when "if (unlikely(next_page == cpu_buffer->commit_page))", ring_buffer
is still available, we should not corrupt it.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
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.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 1d6526361d06..9c1e73da4e30 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -1025,12 +1025,8 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer, } if (next_page == head_page) { - if (!(buffer->flags & RB_FL_OVERWRITE)) { - /* reset write */ - if (tail <= BUF_PAGE_SIZE) - local_set(&tail_page->write, tail); + if (!(buffer->flags & RB_FL_OVERWRITE)) goto out_unlock; - } /* tail_page has not moved yet? */ if (tail_page == cpu_buffer->tail_page) { @@ -1105,6 +1101,10 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer, return event; out_unlock: + /* reset write */ + if (tail <= BUF_PAGE_SIZE) + local_set(&tail_page->write, tail); + __raw_spin_unlock(&cpu_buffer->lock); local_irq_restore(flags); return NULL; |