diff options
Diffstat (limited to '0001-driver-code-clarify-and-fix-platform-device-DMA-mask.patch')
| -rw-r--r-- | 0001-driver-code-clarify-and-fix-platform-device-DMA-mask.patch | 136 |
1 files changed, 0 insertions, 136 deletions
diff --git a/0001-driver-code-clarify-and-fix-platform-device-DMA-mask.patch b/0001-driver-code-clarify-and-fix-platform-device-DMA-mask.patch deleted file mode 100644 index 873509eb0..000000000 --- a/0001-driver-code-clarify-and-fix-platform-device-DMA-mask.patch +++ /dev/null @@ -1,136 +0,0 @@ -From e3a36eb6dfaeea8175c05d5915dcf0b939be6dab Mon Sep 17 00:00:00 2001 -From: Christoph Hellwig <hch@lst.de> -Date: Wed, 11 Mar 2020 17:07:10 +0100 -Subject: [PATCH] driver code: clarify and fix platform device DMA mask - allocation - -This does three inter-related things to clarify the usage of the -platform device dma_mask field. In the process, fix the bug introduced -by cdfee5623290 ("driver core: initialize a default DMA mask for -platform device") that caused Artem Tashkinov's laptop to not boot with -newer Fedora kernels. - -This does: - - - First off, rename the field to "platform_dma_mask" to make it - greppable. - - We have way too many different random fields called "dma_mask" in - various data structures, where some of them are actual masks, and - some of them are just pointers to the mask. And the structures all - have pointers to each other, or embed each other inside themselves, - and "pdev" sometimes means "platform device" and sometimes it means - "PCI device". - - So to make it clear in the code when you actually use this new field, - give it a unique name (it really should be something even more unique - like "platform_device_dma_mask", since it's per platform device, not - per platform, but that gets old really fast, and this is unique - enough in context). - - To further clarify when the field gets used, initialize it when we - actually start using it with the default value. - - - Then, use this field instead of the random one-off allocation in - platform_device_register_full() that is now unnecessary since we now - already have a perfectly fine allocation for it in the platform - device structure. - - - The above then allows us to fix the actual bug, where the error path - of platform_device_register_full() would unconditionally free the - platform device DMA allocation with 'kfree()'. - - That kfree() was dont regardless of whether the allocation had been - done earlier with the (now removed) kmalloc, or whether - setup_pdev_dma_masks() had already been used and the dma_mask pointer - pointed to the mask that was part of the platform device. - -It seems most people never triggered the error path, or only triggered -it from a call chain that set an explicit pdevinfo->dma_mask value (and -thus caused the unnecessary allocation that was "cleaned up" in the -error path) before calling platform_device_register_full(). - -Robin Murphy points out that in Artem's case the wdat_wdt driver failed -in platform_device_add(), and that was the one that had called -platform_device_register_full() with pdevinfo.dma_mask = 0, and would -have caused that kfree() of pdev.dma_mask corrupting the heap. - -A later unrelated kmalloc() then oopsed due to the heap corruption. - -Fixes: cdfee5623290 ("driver core: initialize a default DMA mask for platform device") -Reported-bisected-and-tested-by: Artem S. Tashkinov <aros@gmx.com> -Reviewed-by: Robin Murphy <robin.murphy@arm.com> -Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> -Signed-off-by: Christoph Hellwig <hch@lst.de> -Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> ---- - drivers/base/platform.c | 25 ++++++------------------- - include/linux/platform_device.h | 2 +- - 2 files changed, 7 insertions(+), 20 deletions(-) - -diff --git a/drivers/base/platform.c b/drivers/base/platform.c -index 7fa654f1288b..b5ce7b085795 100644 ---- a/drivers/base/platform.c -+++ b/drivers/base/platform.c -@@ -363,10 +363,10 @@ static void setup_pdev_dma_masks(struct platform_device *pdev) - { - if (!pdev->dev.coherent_dma_mask) - pdev->dev.coherent_dma_mask = DMA_BIT_MASK(32); -- if (!pdev->dma_mask) -- pdev->dma_mask = DMA_BIT_MASK(32); -- if (!pdev->dev.dma_mask) -- pdev->dev.dma_mask = &pdev->dma_mask; -+ if (!pdev->dev.dma_mask) { -+ pdev->platform_dma_mask = DMA_BIT_MASK(32); -+ pdev->dev.dma_mask = &pdev->platform_dma_mask; -+ } - }; - - /** -@@ -662,20 +662,8 @@ struct platform_device *platform_device_register_full( - pdev->dev.of_node_reused = pdevinfo->of_node_reused; - - if (pdevinfo->dma_mask) { -- /* -- * This memory isn't freed when the device is put, -- * I don't have a nice idea for that though. Conceptually -- * dma_mask in struct device should not be a pointer. -- * See http://thread.gmane.org/gmane.linux.kernel.pci/9081 -- */ -- pdev->dev.dma_mask = -- kmalloc(sizeof(*pdev->dev.dma_mask), GFP_KERNEL); -- if (!pdev->dev.dma_mask) -- goto err; -- -- kmemleak_ignore(pdev->dev.dma_mask); -- -- *pdev->dev.dma_mask = pdevinfo->dma_mask; -+ pdev->platform_dma_mask = pdevinfo->dma_mask; -+ pdev->dev.dma_mask = &pdev->platform_dma_mask; - pdev->dev.coherent_dma_mask = pdevinfo->dma_mask; - } - -@@ -700,7 +688,6 @@ struct platform_device *platform_device_register_full( - if (ret) { - err: - ACPI_COMPANION_SET(&pdev->dev, NULL); -- kfree(pdev->dev.dma_mask); - platform_device_put(pdev); - return ERR_PTR(ret); - } -diff --git a/include/linux/platform_device.h b/include/linux/platform_device.h -index 276a03c24691..041bfa412aa0 100644 ---- a/include/linux/platform_device.h -+++ b/include/linux/platform_device.h -@@ -24,7 +24,7 @@ struct platform_device { - int id; - bool id_auto; - struct device dev; -- u64 dma_mask; -+ u64 platform_dma_mask; - u32 num_resources; - struct resource *resource; - --- -2.25.1 - |