[PATCH] Revert "net: mvpp2: debugfs: fix memory leak when using debugfs_lookup()"

[PATCH] Revert "net: mvpp2: debugfs: fix memory leak when using debugfs_lookup()"

[Sasha Levin]

This reverts commit fe2c9c61f668cde28dac2b188028c5299cedcc1e.

On Tue, Sep 13, 2022 at 05:48:58PM +0100, Russell King (Oracle) wrote:
>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.

Revert until a proper fix is available as the original behavior was
better.

Cc: Marcin Wojtas <mw@semihalf.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: netdev@vger.kernel.org
Cc: stable@kernel.org
Reported-by: Russell King <linux@armlinux.org.uk>
Fixes: fe2c9c61f668 ("net: mvpp2: debugfs: fix memory leak when using debugfs_lookup()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/ethernet/marvell/mvpp2/mvpp2_debugfs.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2_debugfs.c b/drivers/net/ethernet/marvell/mvpp2/mvpp2_debugfs.c
index 0eec05d905eb..4a3baa7e0142 100644
--- 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 *priv)
 
 void mvpp2_dbgfs_init(struct mvpp2 *priv, const char *name)
 {
-	static struct dentry *mvpp2_root;
-	struct dentry *mvpp2_dir;
+	struct dentry *mvpp2_dir, *mvpp2_root;
 	int ret, i;
 
+	mvpp2_root = debugfs_lookup(MVPP2_DRIVER_NAME, NULL);
 	if (!mvpp2_root)
 		mvpp2_root = debugfs_create_dir(MVPP2_DRIVER_NAME, NULL);
 
-- 
2.35.1

Re: [PATCH] Revert "net: mvpp2: debugfs: fix memory leak when using debugfs_lookup()"

[Greg Kroah-Hartman]

On Fri, Sep 23, 2022 at 07:47:36PM -0400, Sasha Levin wrote:
> This reverts commit fe2c9c61f668cde28dac2b188028c5299cedcc1e.
> 
> On Tue, Sep 13, 2022 at 05:48:58PM +0100, Russell King (Oracle) wrote:
> >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.
> 
> Revert until a proper fix is available as the original behavior was
> better.
> 
> Cc: Marcin Wojtas <mw@semihalf.com>
> Cc: Russell King <linux@armlinux.org.uk>
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Eric Dumazet <edumazet@google.com>
> Cc: Jakub Kicinski <kuba@kernel.org>
> Cc: Paolo Abeni <pabeni@redhat.com>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: netdev@vger.kernel.org
> Cc: stable@kernel.org
> Reported-by: Russell King <linux@armlinux.org.uk>
> Fixes: fe2c9c61f668 ("net: mvpp2: debugfs: fix memory leak when using debugfs_lookup()")
> Signed-off-by: Sasha Levin <sashal@kernel.org>
> ---
>  drivers/net/ethernet/marvell/mvpp2/mvpp2_debugfs.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Re: [PATCH] Revert "net: mvpp2: debugfs: fix memory leak when using debugfs_lookup()"

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (master)
by Jakub Kicinski <kuba@kernel.org>:

On Fri, 23 Sep 2022 19:47:36 -0400 you wrote:
> This reverts commit fe2c9c61f668cde28dac2b188028c5299cedcc1e.
> 
> On Tue, Sep 13, 2022 at 05:48:58PM +0100, Russell King (Oracle) wrote:
> >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.
> 
> [...]

Here is the summary with links:
  - Revert "net: mvpp2: debugfs: fix memory leak when using debugfs_lookup()"
    https://git.kernel.org/netdev/net/c/6052a4c11fd8

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html