lkml.org 
[lkml]   [2023]   [Feb]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] mtd: spi-nor: fix memory leak when using debugfs_lookup()
On Sat, Sep 24, 2022 at 10:46:22AM +0200, Greg Kroah-Hartman wrote:
> On Fri, Sep 02, 2022 at 04:01:36PM +0200, Michael Walle wrote:
> > Hi,
> >
> > Am 2022-09-02 15:37, schrieb Greg Kroah-Hartman:
> > > When calling debugfs_lookup() the result must have dput() called on it,
> > > otherwise the memory will leak over time. Fix this up to be much
> > > simpler logic and only create the root debugfs directory once when the
> > > driver is first accessed. That resolves the memory leak and makes
> > > things more obvious as to what the intent is.
> > >
> > > Cc: Tudor Ambarus <tudor.ambarus@microchip.com>
> > > Cc: Pratyush Yadav <pratyush@kernel.org>
> > > Cc: Michael Walle <michael@walle.cc>
> > > Cc: Miquel Raynal <miquel.raynal@bootlin.com>
> > > Cc: Richard Weinberger <richard@nod.at>
> > > Cc: Vignesh Raghavendra <vigneshr@ti.com>
> > > Cc: linux-mtd@lists.infradead.org
> > > Cc: stable <stable@kernel.org>
> > > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > > ---
> > > drivers/mtd/spi-nor/debugfs.c | 4 ++--
> > > 1 file changed, 2 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/mtd/spi-nor/debugfs.c
> > > b/drivers/mtd/spi-nor/debugfs.c
> > > index df76cb5de3f9..3aab595e82d1 100644
> > > --- a/drivers/mtd/spi-nor/debugfs.c
> > > +++ b/drivers/mtd/spi-nor/debugfs.c
> > > @@ -228,11 +228,11 @@ static void spi_nor_debugfs_unregister(void *data)
> > >
> > > void spi_nor_debugfs_register(struct spi_nor *nor)
> > > {
> > > - struct dentry *rootdir, *d;
> > > + static struct dentry *rootdir;
> > > + struct dentry *d;
> > > int ret;
> > >
> > > /* Create rootdir once. Will never be deleted again. */
> > > - rootdir = debugfs_lookup(SPI_NOR_DEBUGFS_ROOT, NULL);
> >
> > IIRC I had that one and it didn't work with spi-nor as a module.
> > Wouldn't it try to create the root dir twice if you remove the module
> > and load it again?
>
> Yes it would, that is a use-model I did not consider at all, thanks.
> I'll rework this.

v2 with this fixed up now sent, thanks.

greg k-h

\
 
 \ /
  Last update: 2023-03-27 00:15    [W:0.048 / U:0.108 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site