On Fri, Jun 17, 2016 at 02:24:57PM -0400, Steven Rostedt wrote: > I tried your patch and it works until you remove the module and try > reading the trace again. As I said, you left out later processing. This > should not exit on error. Below is a patch I wrote, and it works well. > > I'll add you as reported by. > > Thanks!
Acked-by: Namhyung Kim <namhy...@kernel.org> Thanks, Namhyung > diff --git a/kernel/trace/trace_printk.c b/kernel/trace/trace_printk.c > index f96f0383f6c6..ad1d6164e946 100644 > --- a/kernel/trace/trace_printk.c > +++ b/kernel/trace/trace_printk.c > @@ -36,6 +36,10 @@ struct trace_bprintk_fmt { > static inline struct trace_bprintk_fmt *lookup_format(const char *fmt) > { > struct trace_bprintk_fmt *pos; > + > + if (!fmt) > + return ERR_PTR(-EINVAL); > + > list_for_each_entry(pos, &trace_bprintk_fmt_list, list) { > if (!strcmp(pos->fmt, fmt)) > return pos; > @@ -57,7 +61,8 @@ void hold_module_trace_bprintk_format(const char **start, > const char **end) > for (iter = start; iter < end; iter++) { > struct trace_bprintk_fmt *tb_fmt = lookup_format(*iter); > if (tb_fmt) { > - *iter = tb_fmt->fmt; > + if (!IS_ERR(tb_fmt)) > + *iter = tb_fmt->fmt; > continue; > } >