The patch below does not apply to the 4.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 63c5395bb7a9777a33f0e7b5906f2c0170a23692 Mon Sep 17 00:00:00 2001

From: Lukas Wunner lukas@wunner.de Date: Wed, 11 Nov 2020 20:07:40 +0100 Subject: [PATCH] spi: bcm-qspi: Fix use-after-free on unbind

bcm_qspi_remove() calls spi_unregister_master() even though bcm_qspi_probe() calls devm_spi_register_master(). The spi_master is therefore unregistered and freed twice on unbind.

Moreover, since commit 0392727c261b ("spi: bcm-qspi: Handle clock probe deferral"), bcm_qspi_probe() leaks the spi_master allocation if the call to devm_clk_get_optional() fails.

Fix by switching over to the new devm_spi_alloc_master() helper which keeps the private data accessible until the driver has unbound and also avoids the spi_master leak on probe.

While at it, fix an ordering issue in bcm_qspi_remove() wherein spi_unregister_master() is called after uninitializing the hardware, disabling the clock and freeing an IRQ data structure. The correct order is to call spi_unregister_master() *before* those teardown steps because bus accesses may still be ongoing until that function returns.

Fixes: fa236a7ef240 ("spi: bcm-qspi: Add Broadcom MSPI driver") Signed-off-by: Lukas Wunner lukas@wunner.de Cc: stable@vger.kernel.org # v4.9+: 123456789abc: spi: Introduce device-managed SPI controller allocation Cc: stable@vger.kernel.org # v4.9+ Cc: Kamal Dasu kdasu.kdev@gmail.com Acked-by: Florian Fainelli f.fainelli@gmail.com Tested-by: Florian Fainelli f.fainelli@gmail.com Link: https://lore.kernel.org/r/5e31a9a59fd1c0d0b795b2fe219f25e5ee855f9d.160512103... Signed-off-by: Mark Brown broonie@kernel.org

diff --git a/drivers/spi/spi-bcm-qspi.c b/drivers/spi/spi-bcm-qspi.c index 14c9d0133bce..c028446c7460 100644 --- a/drivers/spi/spi-bcm-qspi.c +++ b/drivers/spi/spi-bcm-qspi.c @@ -1327,7 +1327,7 @@ int bcm_qspi_probe(struct platform_device *pdev,

data = of_id->data;

- master = spi_alloc_master(dev, sizeof(struct bcm_qspi)); + master = devm_spi_alloc_master(dev, sizeof(struct bcm_qspi)); if (!master) { dev_err(dev, "error allocating spi_master\n"); return -ENOMEM; @@ -1367,21 +1367,17 @@ int bcm_qspi_probe(struct platform_device *pdev,

if (res) { qspi->base[MSPI] = devm_ioremap_resource(dev, res); - if (IS_ERR(qspi->base[MSPI])) { - ret = PTR_ERR(qspi->base[MSPI]); - goto qspi_resource_err; - } + if (IS_ERR(qspi->base[MSPI])) + return PTR_ERR(qspi->base[MSPI]); } else { - goto qspi_resource_err; + return 0; }

res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "bspi"); if (res) { qspi->base[BSPI] = devm_ioremap_resource(dev, res); - if (IS_ERR(qspi->base[BSPI])) { - ret = PTR_ERR(qspi->base[BSPI]); - goto qspi_resource_err; - } + if (IS_ERR(qspi->base[BSPI])) + return PTR_ERR(qspi->base[BSPI]); qspi->bspi_mode = true; } else { qspi->bspi_mode = false; @@ -1392,18 +1388,14 @@ int bcm_qspi_probe(struct platform_device *pdev, res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "cs_reg"); if (res) { qspi->base[CHIP_SELECT] = devm_ioremap_resource(dev, res); - if (IS_ERR(qspi->base[CHIP_SELECT])) { - ret = PTR_ERR(qspi->base[CHIP_SELECT]); - goto qspi_resource_err; - } + if (IS_ERR(qspi->base[CHIP_SELECT])) + return PTR_ERR(qspi->base[CHIP_SELECT]); }

qspi->dev_ids = kcalloc(num_irqs, sizeof(struct bcm_qspi_dev_id), GFP_KERNEL); - if (!qspi->dev_ids) { - ret = -ENOMEM; - goto qspi_resource_err; - } + if (!qspi->dev_ids) + return -ENOMEM;

for (val = 0; val < num_irqs; val++) { irq = -1; @@ -1484,7 +1476,7 @@ int bcm_qspi_probe(struct platform_device *pdev, qspi->xfer_mode.addrlen = -1; qspi->xfer_mode.hp = -1;

- ret = devm_spi_register_master(&pdev->dev, master); + ret = spi_register_master(master); if (ret < 0) { dev_err(dev, "can't register master\n"); goto qspi_reg_err; @@ -1497,8 +1489,6 @@ int bcm_qspi_probe(struct platform_device *pdev, clk_disable_unprepare(qspi->clk); qspi_probe_err: kfree(qspi->dev_ids); -qspi_resource_err: - spi_master_put(master); return ret; } /* probe function to be called by SoC specific platform driver probe */ @@ -1508,10 +1498,10 @@ int bcm_qspi_remove(struct platform_device *pdev) { struct bcm_qspi *qspi = platform_get_drvdata(pdev);

+ spi_unregister_master(qspi->master); bcm_qspi_hw_uninit(qspi); clk_disable_unprepare(qspi->clk); kfree(qspi->dev_ids); - spi_unregister_master(qspi->master);

return 0; }