From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Josh Wu , Brian Norris 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 Message-Id: <20131202191255.819566799@linuxfoundation.org> In-Reply-To: <20131202191248.517975703@linuxfoundation.org> References: <20131202191248.517975703@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Josh Wu 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 Signed-off-by: Brian Norris Signed-off-by: Greg Kroah-Hartman --- 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; }