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mtd: atmel_nand: fix bug driver will in a dead lock if no nand detected

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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>
Cc: <stable@vger.kernel.org> # 3.12
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
This commit is contained in:
Josh Wu 2013-11-05 17:59:07 +08:00 • committed by Brian Norris
parent 97de79e02d
commit a749d13acd
1 changed files with 0 additions and 1 deletions
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1
drivers/mtd/nand/atmel_nand.c
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@ -2142,7 +2142,6 @@ static int __init atmel_nand_probe(struct platform_device *pdev)
if (host->dma_chan)
dma_release_channel(host->dma_chan);
err_nand_ioremap:
platform_driver_unregister(&atmel_nand_nfc_driver);
return res;
}