Messages in this thread Patch in this message | | | Date | Fri, 19 Aug 2022 21:40:37 -0400 | From | Steven Rostedt <> | Subject | [PATCH 2/4] tracing/eprobes: Do not hardcode $comm as a string |
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From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
The variable $comm is hard coded as a string, which is true for both kprobes and uprobes, but for event probes (eprobes) it is a field name. In most cases the "comm" field would be a string, but there's no guarantee of that fact.
Do not assume that comm is a string. Not to mention, it currently forces comm fields to fault, as string processing for event probes is currently broken.
Cc: stable@vger.kernel.org Fixes: 7491e2c44278 ("tracing: Add a probe that attaches to trace events") Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> --- kernel/trace/trace_probe.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c index dec657af363c..23dcd52ad45c 100644 --- a/kernel/trace/trace_probe.c +++ b/kernel/trace/trace_probe.c @@ -622,9 +622,10 @@ static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size, /* * Since $comm and immediate string can not be dereferenced, - * we can find those by strcmp. + * we can find those by strcmp. But ignore for eprobes. */ - if (strcmp(arg, "$comm") == 0 || strncmp(arg, "\\\"", 2) == 0) { + if (!(flags & TPARG_FL_TPOINT) && + strcmp(arg, "$comm") == 0 || strncmp(arg, "\\\"", 2) == 0) { /* The type of $comm must be "string", and not an array. */ if (parg->count || (t && strcmp(t, "string"))) goto out; -- 2.35.1
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