The patch below does not apply to the 4.4-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 e77df3eca12be4b17f13cf9f215cff248c57d98f Mon Sep 17 00:00:00 2001
From: Lukas Wunner lukas@wunner.de Date: Mon, 7 Dec 2020 09:17:04 +0100 Subject: [PATCH] spi: spi-sh: Fix use-after-free on unbind
spi_sh_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: 680c1305e259 ("spi/spi_sh: use spi_unregister_master instead of spi_master_put in remove path") Signed-off-by: Lukas Wunner lukas@wunner.de Cc: stable@vger.kernel.org # v3.0+: 5e844cc37a5c: spi: Introduce device-managed SPI controller allocation Cc: stable@vger.kernel.org # v3.0+ Cc: Axel Lin axel.lin@ingics.com Link: https://lore.kernel.org/r/6d97628b536baf01d5e3e39db61108f84d44c8b2.160728688... Signed-off-by: Mark Brown broonie@kernel.org
diff --git a/drivers/spi/spi-sh.c b/drivers/spi/spi-sh.c index 20bdae5fdf3b..15123a8f41e1 100644 --- a/drivers/spi/spi-sh.c +++ b/drivers/spi/spi-sh.c @@ -440,7 +440,7 @@ static int spi_sh_probe(struct platform_device *pdev) if (irq < 0) return irq;
- master = spi_alloc_master(&pdev->dev, sizeof(struct spi_sh_data)); + master = devm_spi_alloc_master(&pdev->dev, sizeof(struct spi_sh_data)); if (master == NULL) { dev_err(&pdev->dev, "spi_alloc_master error.\n"); return -ENOMEM; @@ -458,16 +458,14 @@ static int spi_sh_probe(struct platform_device *pdev) break; default: dev_err(&pdev->dev, "No support width\n"); - ret = -ENODEV; - goto error1; + return -ENODEV; } ss->irq = irq; ss->master = master; ss->addr = devm_ioremap(&pdev->dev, res->start, resource_size(res)); if (ss->addr == NULL) { dev_err(&pdev->dev, "ioremap error.\n"); - ret = -ENOMEM; - goto error1; + return -ENOMEM; } INIT_LIST_HEAD(&ss->queue); spin_lock_init(&ss->lock); @@ -477,7 +475,7 @@ static int spi_sh_probe(struct platform_device *pdev) ret = request_irq(irq, spi_sh_irq, 0, "spi_sh", ss); if (ret < 0) { dev_err(&pdev->dev, "request_irq error\n"); - goto error1; + return ret; }
master->num_chipselect = 2; @@ -496,9 +494,6 @@ static int spi_sh_probe(struct platform_device *pdev)
error3: free_irq(irq, ss); - error1: - spi_master_put(master); - return ret; }