[PATCH 2/2] net: ethernet: davinci_emac: Fix platform_data overwrite

[PATCH 2/2] net: ethernet: davinci_emac: Fix platform_data overwrite

[Neil Armstrong]

When the DaVinci emac driver is removed and re-probed, the actual
pdev->dev.platform_data is populated with an unwanted valid pointer saved by
the previous davinci_emac_of_get_pdata() call, causing a kernel crash when
calling priv->int_disable() in emac_int_disable().

Unable to handle kernel paging request at virtual address c8622a80
...
[<c0426fb4>] (emac_int_disable) from [<c0427700>] (emac_dev_open+0x290/0x5f8)
[<c0427700>] (emac_dev_open) from [<c04c00ec>] (__dev_open+0xb8/0x120)
[<c04c00ec>] (__dev_open) from [<c04c0370>] (__dev_change_flags+0x88/0x14c)
[<c04c0370>] (__dev_change_flags) from [<c04c044c>] (dev_change_flags+0x18/0x48)
[<c04c044c>] (dev_change_flags) from [<c052bafc>] (devinet_ioctl+0x6b4/0x7ac)
[<c052bafc>] (devinet_ioctl) from [<c04a1428>] (sock_ioctl+0x1d8/0x2c0)
[<c04a1428>] (sock_ioctl) from [<c014f054>] (do_vfs_ioctl+0x41c/0x600)
[<c014f054>] (do_vfs_ioctl) from [<c014f2a4>] (SyS_ioctl+0x6c/0x7c)
[<c014f2a4>] (SyS_ioctl) from [<c000ff60>] (ret_fast_syscall+0x0/0x1c)

Fixes: 42f59967a091 ("net: ethernet: davinci_emac: add OF support")
Cc: Brian Hutchinson <b.hutchman@gmail.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
---
 drivers/net/ethernet/ti/davinci_emac.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/net/ethernet/ti/davinci_emac.c b/drivers/net/ethernet/ti/davinci_emac.c
index e9fe3fb..58d58f0 100644
--- a/drivers/net/ethernet/ti/davinci_emac.c
+++ b/drivers/net/ethernet/ti/davinci_emac.c
@@ -1878,8 +1878,6 @@ davinci_emac_of_get_pdata(struct platform_device *pdev, struct emac_priv *priv)
 		pdata->hw_ram_addr = auxdata->hw_ram_addr;
 	}
 
-	pdev->dev.platform_data = pdata;
-
 	return  pdata;
 }
 
-- 
1.9.1

Re: [PATCH 2/2] net: ethernet: davinci_emac: Fix platform_data overwrite

[David Miller]

From: Neil Armstrong <narmstrong@baylibre.com>
Date: Wed, 20 Apr 2016 10:56:45 +0200

> When the DaVinci emac driver is removed and re-probed, the actual
> pdev->dev.platform_data is populated with an unwanted valid pointer saved by
> the previous davinci_emac_of_get_pdata() call, causing a kernel crash when
> calling priv->int_disable() in emac_int_disable().
> 
> Unable to handle kernel paging request at virtual address c8622a80
> ...
> [<c0426fb4>] (emac_int_disable) from [<c0427700>] (emac_dev_open+0x290/0x5f8)
> [<c0427700>] (emac_dev_open) from [<c04c00ec>] (__dev_open+0xb8/0x120)
> [<c04c00ec>] (__dev_open) from [<c04c0370>] (__dev_change_flags+0x88/0x14c)
> [<c04c0370>] (__dev_change_flags) from [<c04c044c>] (dev_change_flags+0x18/0x48)
> [<c04c044c>] (dev_change_flags) from [<c052bafc>] (devinet_ioctl+0x6b4/0x7ac)
> [<c052bafc>] (devinet_ioctl) from [<c04a1428>] (sock_ioctl+0x1d8/0x2c0)
> [<c04a1428>] (sock_ioctl) from [<c014f054>] (do_vfs_ioctl+0x41c/0x600)
> [<c014f054>] (do_vfs_ioctl) from [<c014f2a4>] (SyS_ioctl+0x6c/0x7c)
> [<c014f2a4>] (SyS_ioctl) from [<c000ff60>] (ret_fast_syscall+0x0/0x1c)
> 
> Fixes: 42f59967a091 ("net: ethernet: davinci_emac: add OF support")
> Cc: Brian Hutchinson <b.hutchman@gmail.com>
> Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>

Applied.