mmc: meson-gx: Free irq in release() callback

Because the irq was requested through device managed resources API
(devm_request_threaded_irq()) it was freed after meson_mmc_remove()
completion, thus after mmc_free_host() has reclaimed meson_host memory.
As this irq is IRQF_SHARED, while using CONFIG_DEBUG_SHIRQ, its handler
get called by free_irq(). So meson_mmc_irq() was called after the
meson_host memory reclamation and was using invalid memory.

We ended up with the following scenario:
device_release_driver()
	meson_mmc_remove()
		mmc_free_host() /* Freeing host memory */
	...
	devres_release_all()
		devm_irq_release()
			__free_irq()
				meson_mmc_irq() /* Uses freed memory */

To avoid this, the irq is released in meson_mmc_remove() and in
mseon_mmc_probe() error path before mmc_free_host() gets called.

Reported-by: Elie Roudninski <xademax@gmail.com>
Signed-off-by: Remi Pommarel <repk@triplefau.lt>
Cc: stable@vger.kernel.org
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

diff --git a/drivers/mmc/host/meson-gx-mmc.c b/drivers/mmc/host/meson-gx-mmc.c
index c2690c1a50ffc1e2a086916d3aa4b870d2c80c07..f115d7c63ffef2a5d1fee06753b4466ece2f065b 100644 (file)
--- a/drivers/mmc/host/meson-gx-mmc.c
+++ b/drivers/mmc/host/meson-gx-mmc.c
@@ -179,6 +179,8 @@ struct meson_host {
        struct sd_emmc_desc *descs;
        dma_addr_t descs_dma_addr;
 
+       int irq;
+
        bool vqmmc_enabled;
 };
 
@@ -1231,7 +1233,7 @@ static int meson_mmc_probe(struct platform_device *pdev)
        struct resource *res;
        struct meson_host *host;
        struct mmc_host *mmc;
-       int ret, irq;
+       int ret;
 
        mmc = mmc_alloc_host(sizeof(struct meson_host), &pdev->dev);
        if (!mmc)
@@ -1276,8 +1278,8 @@ static int meson_mmc_probe(struct platform_device *pdev)
                goto free_host;
        }
 
-       irq = platform_get_irq(pdev, 0);
-       if (irq <= 0) {
+       host->irq = platform_get_irq(pdev, 0);
+       if (host->irq <= 0) {
                dev_err(&pdev->dev, "failed to get interrupt resource.\n");
                ret = -EINVAL;
                goto free_host;
@@ -1331,9 +1333,8 @@ static int meson_mmc_probe(struct platform_device *pdev)
        writel(IRQ_CRC_ERR | IRQ_TIMEOUTS | IRQ_END_OF_CHAIN,
               host->regs + SD_EMMC_IRQ_EN);
 
-       ret = devm_request_threaded_irq(&pdev->dev, irq, meson_mmc_irq,
-                                       meson_mmc_irq_thread, IRQF_SHARED,
-                                       NULL, host);
+       ret = request_threaded_irq(host->irq, meson_mmc_irq,
+                       meson_mmc_irq_thread, IRQF_SHARED, NULL, host);
        if (ret)
                goto err_init_clk;
 
@@ -1351,7 +1352,7 @@ static int meson_mmc_probe(struct platform_device *pdev)
        if (host->bounce_buf == NULL) {
                dev_err(host->dev, "Unable to map allocate DMA bounce buffer.\n");
                ret = -ENOMEM;
-               goto err_init_clk;
+               goto err_free_irq;
        }
 
        host->descs = dma_alloc_coherent(host->dev, SD_EMMC_DESC_BUF_LEN,
@@ -1370,6 +1371,8 @@ static int meson_mmc_probe(struct platform_device *pdev)
 err_bounce_buf:
        dma_free_coherent(host->dev, host->bounce_buf_size,
                          host->bounce_buf, host->bounce_dma_addr);
+err_free_irq:
+       free_irq(host->irq, host);
 err_init_clk:
        clk_disable_unprepare(host->mmc_clk);
 err_core_clk:
@@ -1387,6 +1390,7 @@ static int meson_mmc_remove(struct platform_device *pdev)
 
        /* disable interrupts */
        writel(0, host->regs + SD_EMMC_IRQ_EN);
+       free_irq(host->irq, host);
 
        dma_free_coherent(host->dev, SD_EMMC_DESC_BUF_LEN,
                          host->descs, host->descs_dma_addr);