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author | Lai Jiangshan <laijs@cn.fujitsu.com> | 2009-01-12 11:06:18 +0800 |
---|---|---|
committer | Ingo Molnar <mingo@elte.hu> | 2009-01-15 09:46:40 +0100 |
commit | 6f3b34402e7282cde49dff395d7ea462bf33bf50 (patch) | |
tree | 9f6b01f62bc6065614f3f70aaff11da7f516e383 | |
parent | 428aee1460a75197f0190534b4d610450ee59af1 (diff) | |
download | blackbird-op-linux-6f3b34402e7282cde49dff395d7ea462bf33bf50.tar.gz blackbird-op-linux-6f3b34402e7282cde49dff395d7ea462bf33bf50.zip |
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>
-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 4832ffa5d937..0b9de5a3d699 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -1017,12 +1017,8 @@ __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) { @@ -1097,6 +1093,10 @@ __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; |