Hi, On Tue, 19 Jan 2021 10:41:06 -0500 Steven Rostedt <[email protected]> wrote:
> Masami, > > Looks fine to me. What do you think? Agreed. Since register_kretprobe() checks the address by kprobe_on_func_entry(), if it is not passed, it should always fail to register at last. Acked-by: Masami Hiramatsu <[email protected]> Thank you! > > -- Steve > > > On Tue, 19 Jan 2021 23:10:14 +0800 > Jianlin Lv <[email protected]> wrote: > > > When trying to create kretprobe with the wrong function symbol in tracefs; > > The error is triggered in the register_trace_kprobe() and recorded as > > FAIL_REG_PROBE issue, > > > > Example: > > $ cd /sys/kernel/debug/tracing > > $ echo 'r:myprobe ERROR_SYMBOL_XXX ret=%x0' >> kprobe_events > > bash: echo: write error: Invalid argument > > $ cat error_log > > [142797.347877] trace_kprobe: error: Failed to register probe event > > Command: r:myprobe ERROR_SYMBOL_XXX ret=%x0 > > ^ > > > > This error can be detected in the parameter parsing stage, the effect of > > applying this patch is as follows: > > > > $ echo 'r:myprobe ERROR_SYMBOL_XXX ret=%x0' >> kprobe_events > > bash: echo: write error: Invalid argument > > $ cat error_log > > [415.89]trace_kprobe: error: Retprobe address must be an function entry > > Command: r:myprobe ERROR_SYMBOL_XXX ret=%x0 > > ^ > > > > Signed-off-by: Jianlin Lv <[email protected]> > > --- > > kernel/trace/trace_kprobe.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c > > index e6fba1798771..3dfd1b6711a3 100644 > > --- a/kernel/trace/trace_kprobe.c > > +++ b/kernel/trace/trace_kprobe.c > > @@ -830,7 +830,7 @@ static int trace_kprobe_create(int argc, const char > > *argv[]) > > flags |= TPARG_FL_RETURN; > > if (kprobe_on_func_entry(NULL, symbol, offset)) > > flags |= TPARG_FL_FENTRY; > > - if (offset && is_return && !(flags & TPARG_FL_FENTRY)) { > > + if (is_return && !(flags & TPARG_FL_FENTRY)) { > > trace_probe_log_err(0, BAD_RETPROBE); > > goto parse_error; > > } > -- Masami Hiramatsu <[email protected]>
