Messages in this thread | | | Subject | Re: [RFC PATCH tracing/kprobes 4/5] perf: Support perf kprobe command for kprobe-event setup helper | From | Steven Rostedt <> | Date | Sat, 26 Sep 2009 04:52:00 -0400 |
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On Fri, 2009-09-25 at 12:15 -0700, Masami Hiramatsu wrote:
> + > +#define MAX_CMDLEN 256 > + > +static int synthesize_probepoint(struct probe_point *pp) > +{ > + char *buf; > + int i, len, ret; > + pp->probes[0] = buf = (char *)calloc(MAX_CMDLEN, sizeof(char)); > + len = snprintf(buf, MAX_CMDLEN, "%s+%d", pp->function, pp->offset);
What happens if func and offset is too big for MAX_CMDLEN?
> + for (i = 0; i < pp->nr_args; i++) {
Can you have a case where pp->nr_args == 0?
> + ret = snprintf(&buf[len], MAX_CMDLEN - len, " %s", > + pp->args[i]); > + if (ret <= 0 || ret >= MAX_CMDLEN - len) { > + free(pp->probes[0]); > + return -E2BIG; > + } > + len += ret; > + } > + return pp->found = 1; > +} > + > +int cmd_kprobe(int argc, const char **argv, const char *prefix __used) > +{ > + int i, j, fd, ret, need_dwarf = 0; > + struct probe_point *pp; > + char buf[MAX_CMDLEN]; > + > + argc = parse_options(argc, argv, options, kprobe_usage, > + PARSE_OPT_STOP_AT_NON_OPTION); > + if (argc || session.nr_probe == 0) > + usage_with_options(kprobe_usage, options); > + > + /* Synthesize return probes */ > + for (j = 0; j < session.nr_probe; j++) { > + if (session.events[j][0] != 'r') { > + need_dwarf = 1; > + continue; > + } > + ret = synthesize_probepoint(&session.probes[j]); > + if (ret < 0) > + semantic_error("probe point is too long.");
If we have no args but the func and offset is too big, then this does not catch it. But this depends on if we can have no args.
-- Steve
> + } > + >
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