This is a note to let you know that I've just added the patch titled
tracing/filter: Do not WARN on operand count going below zero
to the 4.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
tracing-filter-do-not-warn-on-operand-count-going-below-zero.patch
and it can be found in the queue-4.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From b4875bbe7e68f139bd3383828ae8e994a0df6d28 Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (Red Hat)" <[email protected]>
Date: Thu, 25 Jun 2015 18:02:29 -0400
Subject: tracing/filter: Do not WARN on operand count going below zero
From: "Steven Rostedt (Red Hat)" <[email protected]>
commit b4875bbe7e68f139bd3383828ae8e994a0df6d28 upstream.
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/[email protected]
Reported-by: Vince Weaver <[email protected]>
Reported-by: Sasha Levin <[email protected]>
Signed-off-by: Steven Rostedt <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
kernel/trace/trace_events_filter.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -1385,7 +1385,9 @@ static int check_preds(struct filter_par
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) {
Patches currently in stable-queue which might be from [email protected] are
queue-4.1/tracing-have-branch-tracer-use-recursive-field-of-task-struct.patch
queue-4.1/tracing-fix-sample-output-of-dynamic-arrays.patch
queue-4.1/tracing-filter-do-not-allow-infix-to-exceed-end-of-string.patch
queue-4.1/tracing-fix-typo-from-static-inlin-to-static-inline.patch
queue-4.1/tracing-filter-do-not-warn-on-operand-count-going-below-zero.patch
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