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author | Linus Torvalds <torvalds@linux-foundation.org> | 2010-12-28 15:54:24 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-12-28 15:54:24 -0800 |
commit | 6f7f41851cc4508b672ab71dd48a154712faf15c (patch) | |
tree | 7eecd1c529e60c220a4376a51f47f83d77a89da2 | |
parent | 82cd19cd93727d494c530ddd6a7338033c3fd86e (diff) | |
parent | e1e359273576ee8fe27021356b064c772ed29af3 (diff) | |
download | linux-6f7f41851cc4508b672ab71dd48a154712faf15c.tar.gz linux-6f7f41851cc4508b672ab71dd48a154712faf15c.tar.bz2 linux-6f7f41851cc4508b672ab71dd48a154712faf15c.zip |
Merge branch 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
ring_buffer: Off-by-one and duplicate events in ring_buffer_read_page
-rw-r--r-- | kernel/trace/ring_buffer.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 9ed509a015d8..bd1c35a4fbcc 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -3853,6 +3853,13 @@ int ring_buffer_read_page(struct ring_buffer *buffer, /* Need to copy one event at a time */ do { + /* We need the size of one event, because + * rb_advance_reader only advances by one event, + * whereas rb_event_ts_length may include the size of + * one or two events. + * We have already ensured there's enough space if this + * is a time extend. */ + size = rb_event_length(event); memcpy(bpage->data + pos, rpage->data + rpos, size); len -= size; @@ -3867,7 +3874,7 @@ int ring_buffer_read_page(struct ring_buffer *buffer, event = rb_reader_event(cpu_buffer); /* Always keep the time extend and data together */ size = rb_event_ts_length(event); - } while (len > size); + } while (len >= size); /* update bpage */ local_set(&bpage->commit, pos); |