From: Stephen Boyd <sboyd@kernel.org>
To: Anton Vorontsov <anton@enomsg.org>, Arnd Bergmann <arnd@arndb.de>,
Catalin Marinas <catalin.marinas@arm.com>,
Colin Cross <ccross@android.com>, Ingo Molnar <mingo@redhat.com>,
Jason Baron <jbaron@akamai.com>,
Jim Cromie <jim.cromie@gmail.com>, Joe Perches <joe@perches.com>,
Joel Fernandes <joel@joelfernandes.org>,
Kees Cook <keescook@chromium.org>,
Laura Abbott <labbott@redhat.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Rob Herring <robh+dt@kernel.org>,
Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>,
Steven Rostedt <rostedt@goodmis.org>,
Tony Luck <tony.luck@intel.com>,
Will Deacon <will.deacon@arm.com>,
devicetree@vger.kernel.org
Cc: Rajendra Nayak <rnayak@codeaurora.org>,
Vivek Gautam <vivek.gautam@codeaurora.org>,
Sibi Sankar <sibis@codeaurora.org>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Ingo Molnar <mingo@kernel.org>,
Tom Zanussi <tom.zanussi@linux.intel.com>,
Prasad Sodagudi <psodagud@codeaurora.org>,
tsoni@codeaurora.org, Bryan Huntsman <bryanh@codeaurora.org>,
Tingwei Zhang <tingwei@codeaurora.org>
Subject: Re: [PATCH 2/6] pstore: Add event tracing support
Date: Mon, 17 Sep 2018 10:38:20 -0700 [thread overview]
Message-ID: <153720590027.119890.15984895820368075914@swboyd.mtv.corp.google.com> (raw)
In-Reply-To: <444d7b13-2653-ba0e-e9e6-a448fded2a77@codeaurora.org>
Quoting Sai Prakash Ranjan (2018-09-11 03:46:01)
> On 9/9/2018 1:57 AM, Sai Prakash Ranjan wrote:
> > +void notrace pstore_event_call(struct trace_event_buffer *fbuffer)
> > +{
> > + struct trace_iterator *iter;
> > + struct trace_seq *s;
> > + struct trace_event_call *event_call;
> > + struct pstore_record record;
> > + struct trace_event *event;
> > + struct seq_buf *seq;
> > + unsigned long flags;
> > +
> > + if (!psinfo)
> > + return;
> > +
> > + if (unlikely(oops_in_progress))
> > + return;
> > +
> > + pstore_record_init(&record, psinfo);
> > + record.type = PSTORE_TYPE_EVENT;
> > +
> > + iter = kmalloc(sizeof(*iter), GFP_KERNEL);
> > + if (!iter)
> > + return;
> > +
> > + 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;
> > + event_call->event.funcs->trace(iter, 0, event);
> > + 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);
> > +
> > +fail_event:
> > + kfree(iter);
> > +}
> > +
> >
>
> When tracing sched events on sdm845 mtp, I hit below bug repeatedly.
> Seems like pstore_event_call can be called in atomic context.
> I will respin the below fix in next version of the patch.
> Reviews on other parts would be appreciated, thanks.
>
> diff --git a/fs/pstore/ftrace.c b/fs/pstore/ftrace.c
> index d47dc93ac098..a497cf782ee8 100644
> --- a/fs/pstore/ftrace.c
> +++ b/fs/pstore/ftrace.c
> @@ -73,6 +73,7 @@ void notrace pstore_event_call(struct
> trace_event_buffer *fbuffer)
> struct trace_event *event;
> struct seq_buf *seq;
> unsigned long flags;
> + gfp_t gfpflags;
>
> if (!psinfo)
> return;
> @@ -83,7 +84,9 @@ void notrace pstore_event_call(struct
> trace_event_buffer *fbuffer)
> pstore_record_init(&record, psinfo);
> record.type = PSTORE_TYPE_EVENT;
>
> - iter = kmalloc(sizeof(*iter), GFP_KERNEL);
> + gfpflags = (in_atomic() || irqs_disabled()) ? GFP_ATOMIC :
> GFP_KERNEL;
> +
Do you need to allocate at all? Can you throw the iter on the stack?
Using in_atomic() and irqs_disabled() to figure out if an atomic or a
non-atomic allocation should be used is not a good solution.
next prev parent reply other threads:[~2018-09-17 17:38 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-08 20:27 [PATCH 0/6] Tracing register accesses with pstore and dynamic debug Sai Prakash Ranjan
2018-09-08 20:27 ` [PATCH 1/6] dt-bindings: ramoops: Add event-size property Sai Prakash Ranjan
[not found] ` <5b9f3f67.1c69fb81.3125b.c205@mx.google.com>
2018-09-17 17:15 ` Sai Prakash Ranjan
2018-09-08 20:27 ` [PATCH 2/6] pstore: Add event tracing support Sai Prakash Ranjan
2018-09-11 10:46 ` Sai Prakash Ranjan
2018-09-17 17:38 ` Stephen Boyd [this message]
2018-09-17 19:43 ` Sai Prakash Ranjan
2018-09-16 7:07 ` Sai Prakash Ranjan
[not found] ` <CAEXW_YSPNqVgoYWjVAMvGg_WoRV4SC2xDH1wQWTdQfBUOMQbbQ@mail.gmail.com>
2018-09-17 14:54 ` Kees Cook
2018-09-17 17:17 ` Sai Prakash Ranjan
2018-09-17 17:13 ` Sai Prakash Ranjan
2018-09-17 23:04 ` Steven Rostedt
2018-09-18 6:24 ` Sai Prakash Ranjan
2018-09-17 23:34 ` Steven Rostedt
2018-09-18 17:52 ` Sai Prakash Ranjan
2018-09-18 20:44 ` Steven Rostedt
2018-09-18 21:13 ` Sai Prakash Ranjan
2018-09-22 6:48 ` Sai Prakash Ranjan
2018-09-22 9:05 ` Joel Fernandes
2018-09-22 16:37 ` Sai Prakash Ranjan
2018-09-22 17:32 ` Sai Prakash Ranjan
2018-09-22 17:45 ` Sai Prakash Ranjan
2018-09-23 15:33 ` Sai Prakash Ranjan
2018-09-25 20:37 ` Joel Fernandes
2018-09-25 20:39 ` Joel Fernandes
2018-09-25 20:40 ` Joel Fernandes
2018-09-26 9:52 ` Sai Prakash Ranjan
2018-09-08 20:27 ` [PATCH 3/6] tracing: Add tp_pstore cmdline to have tracepoints go to pstore Sai Prakash Ranjan
2018-09-25 21:25 ` Joel Fernandes
2018-09-26 9:46 ` Sai Prakash Ranjan
2018-10-08 14:16 ` Sai Prakash Ranjan
2018-10-08 14:36 ` Steven Rostedt
2018-10-08 22:40 ` Joel Fernandes
2018-10-09 18:22 ` Sai Prakash Ranjan
2018-10-10 19:37 ` Steven Rostedt
2018-09-08 20:27 ` [PATCH 4/6] arm64/io: Add tracepoint for register accesses Sai Prakash Ranjan
2018-09-08 20:27 ` [PATCH 5/6] arm64/io: Add header for instrumentation of io operations Sai Prakash Ranjan
2018-09-17 23:39 ` Steven Rostedt
2018-09-18 7:10 ` Sai Prakash Ranjan
2018-09-18 11:47 ` Will Deacon
2018-09-18 12:43 ` Sai Prakash Ranjan
2018-09-08 20:27 ` [PATCH 6/6] dynamic_debug: Add flag for dynamic event tracing Sai Prakash Ranjan
2018-09-11 15:11 ` [PATCH 0/6] Tracing register accesses with pstore and dynamic debug Will Deacon
2018-09-11 16:11 ` Sai Prakash Ranjan
2018-10-20 5:25 ` Joel Fernandes
2018-10-20 6:32 ` Sai Prakash Ranjan
2018-10-20 16:27 ` Joel Fernandes
2018-10-21 3:46 ` Sai Prakash Ranjan
2018-10-21 4:59 ` Sai Prakash Ranjan
2018-10-21 5:09 ` Joel Fernandes
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