Messages in this thread | | | Date | Wed, 8 Feb 2023 13:58:14 +0100 | From | Greg Kroah-Hartman <> | Subject | Re: [PATCH] mtd: spi-nor: fix memory leak when using debugfs_lookup() |
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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
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