2013-05-14 21:50:46

by Sam Bradshaw

Subject: [PATCH][TRIVIAL] mtip32xx: Fix NULL pointer dereference during module unload

An open file-handle to one or more of the driver exported debugfs
nodes causes raciness in recursive removal during module unload;
sometimes a stale parent dentry is dereferenced when more than 1
pci device is present.

Signed-off-by: Sam Bradshaw <[email protected]>
---
diff --git a/drivers/block/mtip32xx/mtip32xx.c
b/drivers/block/mtip32xx/mtip32xx.c
index 847107e..e366c74 100644
--- a/drivers/block/mtip32xx/mtip32xx.c
+++ b/drivers/block/mtip32xx/mtip32xx.c
@@ -3002,7 +3002,8 @@ static int mtip_hw_debugfs_init(struct driver_data
*dd)

static void mtip_hw_debugfs_exit(struct driver_data *dd)
{
- debugfs_remove_recursive(dd->dfs_node);
+ if (dd->dfs_node)
+ debugfs_remove_recursive(dd->dfs_node);
}

2013-05-15 08:05:41

by Jens Axboe

Subject: Re: [PATCH][TRIVIAL] mtip32xx: Fix NULL pointer dereference during module unload

On Tue, May 14 2013, Sam Bradshaw wrote:
> An open file-handle to one or more of the driver exported debugfs
> nodes causes raciness in recursive removal during module unload;
> sometimes a stale parent dentry is dereferenced when more than 1
> pci device is present.

Thanks applied, I hit this one too recently.

--
Jens Axboe