From mboxrd@z Thu Jan 1 00:00:00 1970 From: saiprakash.ranjan@codeaurora.org (Sai Prakash Ranjan) Date: Tue, 18 Sep 2018 23:22:48 +0530 Subject: [PATCH 2/6] pstore: Add event tracing support In-Reply-To: <20180917193426.41c99fd5@gandalf.local.home> References: <20180917193426.41c99fd5@gandalf.local.home> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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? >> + >> + 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? Thanks, Sai -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation