On Tue, 18 Sep 2018 23:22:48 +0530 Sai Prakash Ranjan <saiprakash.ranjan@xxxxxxxxxxxxxx> wrote: > On 9/18/2018 5:04 AM, Steven Rostedt wrote: > > > > It looks like pstore_event_call() gets called from a trace event. You > > can't call kmalloc() from one. One thing is that kmalloc has > > tracepoints itself. You trace those you just entered an infinite loop. > > > > > > Ok will remove it in v2. But any alternative way to do this? I think I describe it below. > > >> + > >> + event_call = fbuffer->trace_file->event_call; > >> + if (!event_call || !event_call->event.funcs || > >> + !event_call->event.funcs->trace) > >> + goto fail_event; > >> + > >> + event = &fbuffer->trace_file->event_call->event; > >> + > >> + spin_lock_irqsave(&psinfo->buf_lock, flags); > >> + > >> + trace_seq_init(&iter->seq); > >> + iter->ent = fbuffer->entry; > > > > I guess what you are doing is needing to translate the raw data into > > ascii output, and need the trace_iterator to do so. > > > > You are already under a psinfo->buf_lock. Add a dummy iterator to that > > and use it instead. > > > > trace_seq_init(&psinfo->iter->seq); > > > >> + event_call->event.funcs->trace(iter, 0, event); > > > > (psinfo->iter, 0 , event); > > > > etc. > > > > Sure, will update in v2. > > >> + trace_seq_putc(&iter->seq, 0); > >> + > >> + if (seq->size > psinfo->bufsize) > >> + seq->size = psinfo->bufsize; > >> + > >> + s = &iter->seq; > >> + seq = &s->seq; > >> + > >> + record.buf = (char *)(seq->buffer); > >> + record.size = seq->len; > >> + psinfo->write(&record); > >> + > >> + spin_unlock_irqrestore(&psinfo->buf_lock, flags); > > > > You may also need to convert these spin_locks into raw_spin_locks as > > when PREEMPT_RT enters the kernel you don't want them to turn into > > mutexes. > > > > But that can be another patch. > > > > I will change this in v2, but can't we have it in same patch? I suggested a separate patch because buf_lock is used elsewhere. Changing it to "raw_spin_lock" will affect more than just what this patch series does. Thus, I recommend making it a separate patch to keep this patch series from being more intrusive than it needs to be. Thanks! -- Steve
