2016-04-20 08:56:56

by Neil Armstrong

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

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 <[email protected]>
Signed-off-by: Neil Armstrong <[email protected]>
---
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

2016-04-21 18:58:17

by David Miller

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

From: Neil Armstrong <[email protected]>
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 <[email protected]>
> Signed-off-by: Neil Armstrong <[email protected]>

Applied.