From: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx> commit 02333de90e5945e2fe7fc75b15b4eb9aee187f0a upstream. 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. Link: https://lkml.kernel.org/r/20220820134400.756152112@xxxxxxxxxxx Cc: stable@xxxxxxxxxxxxxxx Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx> Cc: Tzvetomir Stoyanov <tz.stoyanov@xxxxxxxxx> Cc: Tom Zanussi <zanussi@xxxxxxxxxx> Fixes: 7491e2c44278 ("tracing: Add a probe that attaches to trace events") Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- kernel/trace/trace_probe.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/kernel/trace/trace_probe.c +++ b/kernel/trace/trace_probe.c @@ -618,9 +618,10 @@ static int traceprobe_parse_probe_arg_bo /* * 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;
