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| author | Steven Rostedt (Red Hat) <rostedt@goodmis.org> | 2015-06-25 18:02:29 -0400 |
|---|---|---|
| committer | Sasha Levin <sasha.levin@oracle.com> | 2015-08-04 14:30:09 -0400 |
| commit | 8c9482a9bc47fee04173956f1fa05eada7779d82 (patch) | |
| tree | 86a4fc5df4afe0bd1b6dbf32f5d8741a9a4f1aaf /kernel | |
| parent | 0ff74faa025bbc4f751785ba34a2c121e9dcc685 (diff) | |
| download | lwn-8c9482a9bc47fee04173956f1fa05eada7779d82.tar.gz lwn-8c9482a9bc47fee04173956f1fa05eada7779d82.zip | |
tracing/filter: Do not WARN on operand count going below zero
[ Upstream commit b4875bbe7e68f139bd3383828ae8e994a0df6d28 ]
When testing the fix for the trace filter, I could not come up with
a scenario where the operand count goes below zero, so I added a
WARN_ON_ONCE(cnt < 0) to the logic. But there is legitimate case
that it can happen (although the filter would be wrong).
# echo '>' > /sys/kernel/debug/events/ext4/ext4_truncate_exit/filter
That is, a single operation without any operands will hit the path
where the WARN_ON_ONCE() can trigger. Although this is harmless,
and the filter is reported as a error. But instead of spitting out
a warning to the kernel dmesg, just fail nicely and report it via
the proper channels.
Link: http://lkml.kernel.org/r/558C6082.90608@oracle.com
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Cc: stable@vger.kernel.org # 2.6.33+
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/trace/trace_events_filter.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index 51afcb76d32b..357b1ddf088b 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -1383,7 +1383,9 @@ static int check_preds(struct filter_parse_state *ps) continue; } n_normal_preds++; - WARN_ON_ONCE(cnt < 0); + /* all ops should have operands */ + if (cnt < 0) + break; } if (cnt != 1 || !n_normal_preds || n_logical_preds >= n_normal_preds) { |