| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.12 071/212] mtd: atmel_nand: fix bug driver will in a dead lock if no nand detected | Date | Mon, 2 Dec 2013 11:14:22 -0800 |
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3.12-stable review patch. If anyone has any objections, please let me know.
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From: Josh Wu <josh.wu@atmel.com>
commit a749d13acd8e079ed4c77a9456d842dc94af8f17 upstream.
In the atmel driver probe function, the code shows like following: atmel_nand_probe(...) { ...
err_nand_ioremap: platform_driver_unregister(&atmel_nand_nfc_driver); return res; }
If no nand flash detected, the driver probe function will goto err_nand_ioremap label. Then platform_driver_unregister() will be called. It will get the lock of atmel_nand device since it is parent of nfc_device. The problem is the lock is already hold by atmel_nand_probe itself. So system will be in a dead lock.
This patch just simply removed to platform_driver_unregister() call. When atmel_nand driver is quit the platform_driver_unregister() will be called in atmel_nand_remove().
[Brian: the NAND platform probe really has no business registering/unregistering another driver; this fixes the deadlock, but we should follow up the likely racy behavior here with a better architecture]
Signed-off-by: Josh Wu <josh.wu@atmel.com> Signed-off-by: Brian Norris <computersforpeace@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/mtd/nand/atmel_nand.c | 1 - 1 file changed, 1 deletion(-)
--- a/drivers/mtd/nand/atmel_nand.c +++ b/drivers/mtd/nand/atmel_nand.c @@ -2177,7 +2177,6 @@ err_no_card: if (host->dma_chan) dma_release_channel(host->dma_chan); err_nand_ioremap: - platform_driver_unregister(&atmel_nand_nfc_driver); return res; }
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