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authorSteven Rostedt (Red Hat) <rostedt@goodmis.org>2015-11-24 01:35:24 +0300
committerSteven Rostedt <rostedt@goodmis.org>2015-11-24 17:27:25 +0300
commitbd1b7cd360f529394936f28746eb4aaa12d6770a (patch)
tree7ff2c87020172dee449997bda223f1900b43a5f3 /kernel/trace
parentb81f472a208d3e2b4392faa6d17037a89442f4ce (diff)
downloadlinux-bd1b7cd360f529394936f28746eb4aaa12d6770a.tar.xz
ring-buffer: Put back the length if crossed page with add_timestamp
Commit fcc742eaad7c "ring-buffer: Add event descriptor to simplify passing data" added a descriptor that holds various data instead of passing around several variables through parameters. The problem was that one of the parameters was modified in a function and the code was designed not to have an effect on that modified parameter. Now that the parameter is a descriptor and any modifications to it are non-volatile, the size of the data could be unnecessarily expanded. Remove the extra space added if a timestamp was added and the event went across the page. Cc: stable@vger.kernel.org # 4.3+ Fixes: fcc742eaad7c "ring-buffer: Add event descriptor to simplify passing data" Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace')
-rw-r--r--kernel/trace/ring_buffer.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 4dd6d5bc4e11..9c6045a27ba3 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -2797,8 +2797,11 @@ rb_reserve_next_event(struct ring_buffer *buffer,
event = __rb_reserve_next(cpu_buffer, &info);
- if (unlikely(PTR_ERR(event) == -EAGAIN))
+ if (unlikely(PTR_ERR(event) == -EAGAIN)) {
+ if (info.add_timestamp)
+ info.length -= RB_LEN_TIME_EXTEND;
goto again;
+ }
if (!event)
goto out_fail;