The patch below does not apply to the 4.19-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 e13ee6cc4781edaf8c7321bee19217e3702ed481 Mon Sep 17 00:00:00 2001
From: Lukas Wunner lukas@wunner.de Date: Wed, 11 Nov 2020 20:07:30 +0100 Subject: [PATCH] spi: bcm2835aux: Fix use-after-free on unbind
bcm2835aux_spi_remove() accesses the driver's private data after calling spi_unregister_master() even though that function releases the last reference on the spi_master and thereby frees the private data.
Fix by switching over to the new devm_spi_alloc_master() helper which keeps the private data accessible until the driver has unbound.
Fixes: b9dd3f6d4172 ("spi: bcm2835aux: Fix controller unregister order") Signed-off-by: Lukas Wunner lukas@wunner.de Cc: stable@vger.kernel.org # v4.4+: 123456789abc: spi: Introduce device-managed SPI controller allocation Cc: stable@vger.kernel.org # v4.4+: b9dd3f6d4172: spi: bcm2835aux: Fix controller unregister order Cc: stable@vger.kernel.org # v4.4+ Link: https://lore.kernel.org/r/b290b06357d0c0bdee9cecc539b840a90630f101.160512103... Signed-off-by: Mark Brown broonie@kernel.org
diff --git a/drivers/spi/spi-bcm2835aux.c b/drivers/spi/spi-bcm2835aux.c index 03b034c15d2b..fd58547110e6 100644 --- a/drivers/spi/spi-bcm2835aux.c +++ b/drivers/spi/spi-bcm2835aux.c @@ -494,7 +494,7 @@ static int bcm2835aux_spi_probe(struct platform_device *pdev) unsigned long clk_hz; int err;
- master = spi_alloc_master(&pdev->dev, sizeof(*bs)); + master = devm_spi_alloc_master(&pdev->dev, sizeof(*bs)); if (!master) return -ENOMEM;
@@ -524,29 +524,24 @@ static int bcm2835aux_spi_probe(struct platform_device *pdev)
/* the main area */ bs->regs = devm_platform_ioremap_resource(pdev, 0); - if (IS_ERR(bs->regs)) { - err = PTR_ERR(bs->regs); - goto out_master_put; - } + if (IS_ERR(bs->regs)) + return PTR_ERR(bs->regs);
bs->clk = devm_clk_get(&pdev->dev, NULL); if (IS_ERR(bs->clk)) { - err = PTR_ERR(bs->clk); dev_err(&pdev->dev, "could not get clk: %d\n", err); - goto out_master_put; + return PTR_ERR(bs->clk); }
bs->irq = platform_get_irq(pdev, 0); - if (bs->irq <= 0) { - err = bs->irq ? bs->irq : -ENODEV; - goto out_master_put; - } + if (bs->irq <= 0) + return bs->irq ? bs->irq : -ENODEV;
/* this also enables the HW block */ err = clk_prepare_enable(bs->clk); if (err) { dev_err(&pdev->dev, "could not prepare clock: %d\n", err); - goto out_master_put; + return err; }
/* just checking if the clock returns a sane value */ @@ -581,8 +576,6 @@ static int bcm2835aux_spi_probe(struct platform_device *pdev)
out_clk_disable: clk_disable_unprepare(bs->clk); -out_master_put: - spi_master_put(master); return err; }