From d8f7a5484f2188e9af2d9e4e587587d724501b12 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?M=C3=A5rten=20Lindahl?= Date: Wed, 16 Feb 2022 10:41:28 +0100 Subject: [PATCH] driver core: Free DMA range map when device is released MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When unbinding/binding a driver with DMA mapped memory, the DMA map is not freed before the driver is reloaded. This leads to a memory leak when the DMA map is overwritten when reprobing the driver. This can be reproduced with a platform driver having a dma-range: dummy { ... #address-cells = <0x2>; #size-cells = <0x2>; ranges; dma-ranges = <...>; ... }; and then unbinding/binding it: ~# echo soc:dummy >/sys/bus/platform/drivers//unbind DMA map object 0xffffff800b0ae540 still being held by &pdev->dev ~# echo soc:dummy >/sys/bus/platform/drivers//bind ~# echo scan > /sys/kernel/debug/kmemleak ~# cat /sys/kernel/debug/kmemleak unreferenced object 0xffffff800b0ae540 (size 64): comm "sh", pid 833, jiffies 4295174550 (age 2535.352s) hex dump (first 32 bytes): 00 00 00 80 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 80 00 00 00 00 00 00 00 80 00 00 00 00 ................ backtrace: [] create_object.isra.0+0x108/0x344 [] kmemleak_alloc+0x8c/0xd0 [] __kmalloc+0x440/0x6f0 [] of_dma_get_range+0x124/0x220 [] of_dma_configure_id+0x40/0x2d0 [] platform_dma_configure+0x5c/0xa4 [] really_probe+0x8c/0x514 [] __driver_probe_device+0x9c/0x19c [] device_driver_attach+0x54/0xbc [] bind_store+0xc4/0x120 [] drv_attr_store+0x30/0x44 [] sysfs_kf_write+0x50/0x60 [] kernfs_fop_write_iter+0x124/0x1b4 [] new_sync_write+0xdc/0x160 [] vfs_write+0x23c/0x2a0 [] ksys_write+0x64/0xec To prevent this we should free the dma_range_map when the device is released. Fixes: e0d072782c73 ("dma-mapping: introduce DMA range map, supplanting dma_pfn_offset") Cc: stable Suggested-by: Rob Herring Reviewed-by: Rob Herring Signed-off-by: Mårten Lindahl Link: https://lore.kernel.org/r/20220216094128.4025861-1-marten.lindahl@axis.com Signed-off-by: Greg Kroah-Hartman --- drivers/base/dd.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 9eaaff2f556c..f47cab21430f 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -629,6 +629,9 @@ re_probe: drv->remove(dev); devres_release_all(dev); + arch_teardown_dma_ops(dev); + kfree(dev->dma_range_map); + dev->dma_range_map = NULL; driver_sysfs_remove(dev); dev->driver = NULL; dev_set_drvdata(dev, NULL); @@ -1209,6 +1212,8 @@ static void __device_release_driver(struct device *dev, struct device *parent) devres_release_all(dev); arch_teardown_dma_ops(dev); + kfree(dev->dma_range_map); + dev->dma_range_map = NULL; dev->driver = NULL; dev_set_drvdata(dev, NULL); if (dev->pm_domain && dev->pm_domain->dismiss)