From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Namhyung Kim <namhyung@kernel.org>,
Daniel Bristot de Oliveira <bristot@redhat.com>,
stable@vger.kernel.org, Tom Zanussi <zanussi@kernel.org>
Subject: [for-linus][PATCH 1/3] tracing/histograms: Fix parsing of "sym-offset" modifier
Date: Fri, 09 Jul 2021 09:09:50 -0400 [thread overview]
Message-ID: <20210709131042.787880276@goodmis.org> (raw)
In-Reply-To: 20210709130949.717206727@goodmis.org
From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
With the addition of simple mathematical operations (plus and minus), the
parsing of the "sym-offset" modifier broke, as it took the '-' part of the
"sym-offset" as a minus, and tried to break it up into a mathematical
operation of "field.sym - offset", in which case it failed to parse
(unless the event had a field called "offset").
Both .sym and .sym-offset modifiers should not be entered into
mathematical calculations anyway. If ".sym-offset" is found in the
modifier, then simply make it not an operation that can be calculated on.
Link: https://lkml.kernel.org/r/20210707110821.188ae255@oasis.local.home
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Daniel Bristot de Oliveira <bristot@redhat.com>
Cc: stable@vger.kernel.org
Fixes: 100719dcef447 ("tracing: Add simple expression support to hist triggers")
Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
kernel/trace/trace_events_hist.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index ba03b7d84fc2..0207aeed31e6 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -1555,6 +1555,13 @@ static int contains_operator(char *str)
switch (*op) {
case '-':
+ /*
+ * Unfortunately, the modifier ".sym-offset"
+ * can confuse things.
+ */
+ if (op - str >= 4 && !strncmp(op - 4, ".sym-offset", 11))
+ return FIELD_OP_NONE;
+
if (*str == '-')
field_op = FIELD_OP_UNARY_MINUS;
else
--
2.30.2
next prev parent reply other threads:[~2021-07-09 13:10 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-09 13:09 [for-linus][PATCH 0/3] tracing: Some minor clean ups and fixes for 5.14 Steven Rostedt
2021-07-09 13:09 ` Steven Rostedt [this message]
2021-07-09 13:09 ` [for-linus][PATCH 2/3] tracing/selftests: Add tests to test histogram sym and sym-offset modifiers Steven Rostedt
2021-07-09 13:09 ` [for-linus][PATCH 3/3] ftrace: Use list_move instead of list_del/list_add Steven Rostedt
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