On Tue, Sep 13, 2022 at 04:01:51PM +0200, Greg Kroah-Hartman wrote: > From: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > > commit fe2c9c61f668cde28dac2b188028c5299cedcc1e upstream. > > 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: Marcin Wojtas <mw@xxxxxxxxxxxx> > Cc: Russell King <linux@xxxxxxxxxxxxxxx> > Cc: "David S. Miller" <davem@xxxxxxxxxxxxx> > Cc: Eric Dumazet <edumazet@xxxxxxxxxx> > Cc: Jakub Kicinski <kuba@xxxxxxxxxx> > Cc: Paolo Abeni <pabeni@xxxxxxxxxx> > Cc: netdev@xxxxxxxxxxxxxxx > Cc: stable <stable@xxxxxxxxxx> > Fixes: 21da57a23125 ("net: mvpp2: add a debugfs interface for the Header Parser") > Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > --- > drivers/net/ethernet/marvell/mvpp2/mvpp2_debugfs.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > --- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_debugfs.c > +++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_debugfs.c > @@ -700,10 +700,10 @@ void mvpp2_dbgfs_cleanup(struct mvpp2 *p > > void mvpp2_dbgfs_init(struct mvpp2 *priv, const char *name) > { > - struct dentry *mvpp2_dir, *mvpp2_root; > + static struct dentry *mvpp2_root; > + struct dentry *mvpp2_dir; > int ret, i; > > - mvpp2_root = debugfs_lookup(MVPP2_DRIVER_NAME, NULL); > if (!mvpp2_root) > mvpp2_root = debugfs_create_dir(MVPP2_DRIVER_NAME, NULL); This looks broken to me. What happens if this is built as a module, and the module is loaded, binds (and creates the directory), then is removed, and then re- inserted? Nothing removes the old directory, so doesn't debugfs_create_dir() fail, resulting in subsequent failure to add any subsequent debugfs entries? I don't think this patch should be backported to stable trees until this point is addressed. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!