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[104.57.184.186]) by smtp.gmail.com with ESMTPSA id i5sm6210777otj.3.2022.01.17.14.31.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 17 Jan 2022 14:31:28 -0800 (PST) Date: Mon, 17 Jan 2022 16:31:23 -0600 From: Bjorn Andersson To: Mathieu Poirier Cc: Miaoqian Lin , linux-kernel@vger.kernel.org, linux-remoteproc@vger.kernel.org, ohad@wizery.com Subject: Re: [PATCH v3] remoteproc: Fix NULL vs IS_ERR() checking in rproc_create_trace_file Message-ID: References: <20220105064201.3907-1-linmq006@gmail.com> <20220105131022.25247-1-linmq006@gmail.com> <20220117170600.GA1119324@p14s> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220117170600.GA1119324@p14s> Precedence: bulk List-ID: X-Mailing-List: linux-remoteproc@vger.kernel.org On Mon 17 Jan 11:06 CST 2022, Mathieu Poirier wrote: > On Wed, Jan 05, 2022 at 01:10:22PM +0000, Miaoqian Lin wrote: > > The debugfs_create_file() function doesn't return NULL. > > It returns error pointers. Fix check in rproc_create_trace_file > > and make it returns return error pointers. > > s/"returns return"/return > > > Fix check in rproc_handle_trace to propagate the error code. > > > > Signed-off-by: Miaoqian Lin > > --- > > Changes in v2: > > - return PTR_ERR(tfile) in rproc_create_trace_file > > - fix check in rproc_handle_trace() > > Changes in v3: > > - return tfile to fix incorrect return type in v2 > > --- > > drivers/remoteproc/remoteproc_core.c | 6 ++++-- > > drivers/remoteproc/remoteproc_debugfs.c | 4 +--- > > 2 files changed, 5 insertions(+), 5 deletions(-) > > > > I will fix the above, add a proper "Fixes" tag and apply this patch to > rproc-next when v5.17-rc1 comes out next week. > We're actually not supposed to check debugfs_create_*() for errors. > Thanks, > Mathieu > > > diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c > > index 775df165eb45..5608408f8eac 100644 > > --- a/drivers/remoteproc/remoteproc_core.c > > +++ b/drivers/remoteproc/remoteproc_core.c > > @@ -656,6 +656,7 @@ static int rproc_handle_trace(struct rproc *rproc, void *ptr, > > struct rproc_debug_trace *trace; > > struct device *dev = &rproc->dev; > > char name[15]; > > + int ret; > > > > if (sizeof(*rsc) > avail) { > > dev_err(dev, "trace rsc is truncated\n"); > > @@ -684,9 +685,10 @@ static int rproc_handle_trace(struct rproc *rproc, void *ptr, > > > > /* create the debugfs entry */ > > trace->tfile = rproc_create_trace_file(name, rproc, trace); > > - if (!trace->tfile) { > > + if (IS_ERR(trace->tfile)) { > > + ret = PTR_ERR(trace->tfile); > > kfree(trace); > > - return -EINVAL; > > + return ret; And actually catching and propagating the error here means that we will start failing rproc_boot() for firmware including a RSC_TRACE when debugfs is disabled... So if we really want to save the heap space we should at least cleanly ignore the error, by cleaning up and returning 0 here. > > } > > > > list_add_tail(&trace->node, &rproc->traces); > > diff --git a/drivers/remoteproc/remoteproc_debugfs.c b/drivers/remoteproc/remoteproc_debugfs.c > > index b5a1e3b697d9..2ae59a365b7e 100644 > > --- a/drivers/remoteproc/remoteproc_debugfs.c > > +++ b/drivers/remoteproc/remoteproc_debugfs.c > > @@ -390,10 +390,8 @@ struct dentry *rproc_create_trace_file(const char *name, struct rproc *rproc, > > > > tfile = debugfs_create_file(name, 0400, rproc->dbg_dir, trace, > > &trace_rproc_ops); > > - if (!tfile) { > > + if (IS_ERR(tfile)) > > dev_err(&rproc->dev, "failed to create debugfs trace entry\n"); And I therefor think this function would be better reduced to: return debugfs_create_file(...); Regards, Bjorn > > - return NULL; > > - } > > > > return tfile; > > } > > -- > > 2.17.1 > >