linux-kernel - Re: [PATCH 04/23] gpiolib: Fix resource leaks on errors in lineinfo_changed

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Message-ID: <CAMRc=Mc65Oo9hHNXu3pxv-9PqgBnbWLyKYaPO5C9R5s07bkB2Q@mail.gmail.com>
Date: Tue, 20 Jan 2026 09:49:06 +0100
From: Bartosz Golaszewski <brgl@...nel.org>
To: Tzung-Bi Shih <tzungbi@...nel.org>
Cc: Jonathan Corbet <corbet@....net>, Shuah Khan <shuah@...nel.org>, linux-doc@...r.kernel.org, 
	linux-kernel@...r.kernel.org, chrome-platform@...ts.linux.dev, 
	linux-kselftest@...r.kernel.org, 
	Laurent Pinchart <laurent.pinchart@...asonboard.com>, 
	Wolfram Sang <wsa+renesas@...g-engineering.com>, Simona Vetter <simona.vetter@...ll.ch>, 
	Dan Williams <dan.j.williams@...el.com>, Jason Gunthorpe <jgg@...dia.com>, linux-gpio@...r.kernel.org, 
	stable@...r.kernel.org, Benson Leung <bleung@...omium.org>, 
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>, "Rafael J . Wysocki" <rafael@...nel.org>, 
	Danilo Krummrich <dakr@...nel.org>, Linus Walleij <linusw@...nel.org>
Subject: Re: [PATCH 04/23] gpiolib: Fix resource leaks on errors in lineinfo_changed_notify()

On Tue, Jan 20, 2026 at 4:11 AM Tzung-Bi Shih <tzungbi@...nel.org> wrote:
>
> On Fri, Jan 16, 2026 at 01:26:01PM +0000, Bartosz Golaszewski wrote:
> > On Fri, 16 Jan 2026 09:10:17 +0100, Tzung-Bi Shih <tzungbi@...nel.org> said:
> > > On error handling paths, lineinfo_changed_notify() doesn't free the
> > > allocated resources which results leaks.  Fix it.
> > >
> > > Cc: stable@...r.kernel.org
> > > Fixes: d4cd0902c156 ("gpio: cdev: make sure the cdev fd is still active before emitting events")
> > > Signed-off-by: Tzung-Bi Shih <tzungbi@...nel.org>
> > > ---
> > >  drivers/gpio/gpiolib-cdev.c | 5 ++++-
> > >  1 file changed, 4 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
> > > index ba1eae15852d..6196aab5ed74 100644
> > > --- a/drivers/gpio/gpiolib-cdev.c
> > > +++ b/drivers/gpio/gpiolib-cdev.c
> > > @@ -2549,7 +2549,7 @@ static int lineinfo_changed_notify(struct notifier_block *nb,
> > >     ctx = kzalloc(sizeof(*ctx), GFP_ATOMIC);
> > >     if (!ctx) {
> > >             pr_err("Failed to allocate memory for line info notification\n");
> > > -           return NOTIFY_DONE;
> > > +           goto err_put_fp;
> > >     }
> > >
> > >     ctx->chg.event_type = action;
> > > @@ -2563,6 +2563,9 @@ static int lineinfo_changed_notify(struct notifier_block *nb,
> > >     queue_work(ctx->gdev->line_state_wq, &ctx->work);
> > >
> > >     return NOTIFY_OK;
> > > +err_put_fp:
> > > +   fput(fp);
> > > +   return NOTIFY_DONE;
> > >  }
> > >
> > >  static int gpio_device_unregistered_notify(struct notifier_block *nb,
> > > --
> > > 2.52.0.457.g6b5491de43-goog
> > >
> > >
> >
> > There's only one place where you need this fput(), please do it directly in
> > the error path of kzalloc() and drop the label.
>
> Sure, just wanted to give a heads up: 17/23 might introduce the label back.
>
> v2: https://lore.kernel.org/all/20260120030857.2144847-1-tzungbi@kernel.org

That's alright, we prefer a smaller patch for backporting.

Bart