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authorSteven Rostedt (Red Hat) <rostedt@goodmis.org>2015-06-25 18:02:29 -0400
committerSteven Rostedt <rostedt@goodmis.org>2015-06-25 18:02:29 -0400
commitb4875bbe7e68f139bd3383828ae8e994a0df6d28 (patch)
tree8f0447111b6a91b8f3c8d33ee89d4120312c7955 /kernel
parent2cf30dc180cea808077f003c5116388183e54f9e (diff)
downloadlinux-b4875bbe7e68f139bd3383828ae8e994a0df6d28.tar.bz2
tracing/filter: Do not WARN on operand count going below zero
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>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/trace_events_filter.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 7f2e97ce71a7..2900d7723d97 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -1385,7 +1385,9 @@ static int check_preds(struct filter_parse_state *ps)
if (elt->op != OP_NOT)
cnt--;
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) {