Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933510Ab3DJBrF (ORCPT ); Tue, 9 Apr 2013 21:47:05 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:27438 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751300Ab3DJBrD (ORCPT ); Tue, 9 Apr 2013 21:47:03 -0400 X-Authority-Analysis: v=2.0 cv=C51rOHz+ c=1 sm=0 a=rXTBtCOcEpjy1lPqhTCpEQ==:17 a=mNMOxpOpBa8A:10 a=i53ZzN_X_rgA:10 a=5SG0PmZfjMsA:10 a=IkcTkHD0fZMA:10 a=meVymXHHAAAA:8 a=NxKs5EB5JOMA:10 a=57SyGIRnAAAA:8 a=VwQbUJbxAAAA:8 a=VyHSx0iAlL1JR8HDaVEA:9 a=QEXdDO2ut3YA:10 a=TIV7c6GJmisA:10 a=jeBq3FmKZ4MA:10 a=LI9Vle30uBYA:10 a=rXTBtCOcEpjy1lPqhTCpEQ==:117 X-Cloudmark-Score: 0 X-Authenticated-User: X-Originating-IP: 74.67.115.198 Message-ID: <1365558422.25498.93.camel@gandalf.local.home> Subject: Re: [PATCH 3/3] tracing: Check cpu file on tracing_release() From: Steven Rostedt To: Namhyung Kim Cc: Namhyung Kim , Frederic Weisbecker , LKML Date: Tue, 09 Apr 2013 21:47:02 -0400 In-Reply-To: <878v4rtbog.fsf@sejong.aot.lge.com> References: <1365553093-10180-1-git-send-email-namhyung@kernel.org> <1365553093-10180-3-git-send-email-namhyung@kernel.org> <1365553863.25498.84.camel@gandalf.local.home> <5164B3F0.2030506@lge.com> <1365554787.25498.88.camel@gandalf.local.home> <878v4rtbog.fsf@sejong.aot.lge.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.4.4-2 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2742 Lines: 83 On Wed, 2013-04-10 at 10:30 +0900, Namhyung Kim wrote: > >From 7ba245dba217ef858b467552019acd49f7fdce7e Mon Sep 17 00:00:00 2001 > From: Namhyung Kim > Date: Wed, 10 Apr 2013 09:10:44 +0900 > Subject: [PATCH] tracing: Check result of ring_buffer_read_prepare() > > The ring_buffer_read_prepare() can return NULL if memory allocation > fails. Fail out in this case instead of succedding and then having > no output. > > Suggested-by: Steven Rostedt > Signed-off-by: Namhyung Kim > --- > kernel/trace/trace.c | 25 +++++++++++++++++++++++++ > 1 file changed, 25 insertions(+) > > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c > index 7270460cfe3c..3b3514dc8e5e 100644 > --- a/kernel/trace/trace.c > +++ b/kernel/trace/trace.c > @@ -2826,6 +2826,8 @@ __tracing_open(struct inode *inode, struct file *file, bool snapshot) > for_each_tracing_cpu(cpu) { > iter->buffer_iter[cpu] = > ring_buffer_read_prepare(iter->trace_buffer->buffer, cpu); > + if (!iter->buffer_iter[cpu]) > + goto free; > } > ring_buffer_read_prepare_sync(); > for_each_tracing_cpu(cpu) { > @@ -2836,6 +2838,9 @@ __tracing_open(struct inode *inode, struct file *file, bool snapshot) > cpu = iter->cpu_file; > iter->buffer_iter[cpu] = > ring_buffer_read_prepare(iter->trace_buffer->buffer, cpu); > + if (!iter->buffer_iter[cpu]) > + goto free; > + > ring_buffer_read_prepare_sync(); > ring_buffer_read_start(iter->buffer_iter[cpu]); > tracing_iter_reset(iter, cpu); > @@ -2847,6 +2852,26 @@ __tracing_open(struct inode *inode, struct file *file, bool snapshot) > > return iter; > > +free: > + if (iter->cpu_file == RING_BUFFER_ALL_CPUS) { > + for_each_tracing_cpu(cpu) { > + if (iter->buffer_iter[cpu]) > + ring_buffer_read_finish(iter->buffer_iter[cpu]); > + } > + } else { > + cpu = iter->cpu_file; > + if (iter->buffer_iter[cpu]) > + ring_buffer_read_finish(iter->buffer_iter[cpu]); > + } As I said I would consider updating the release code, but here, it's an error path that is extremely unlikely to be hit. Please just keep the single loop, and leave out the cpu_file compare. Thanks, -- Steve > + > + if (iter->trace && iter->trace->close) > + iter->trace->close(iter); > + > + if (!iter->snapshot) > + tracing_start_tr(tr); > + > + mutex_destroy(&iter->mutex); > + free_cpumask_var(iter->started); > fail: > mutex_unlock(&trace_types_lock); > kfree(iter->trace); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/