From d8f7a5484f2188e9af2d9e4e587587d724501b12 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?M=C3=A5rten=20Lindahl?= <marten.lindahl@axis.com>
Date: Wed, 16 Feb 2022 10:41:28 +0100
Subject: [PATCH] driver core: Free DMA range map when device is released
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Git-commit: d8f7a5484f2188e9af2d9e4e587587d724501b12
Patch-mainline: v5.17-rc6
References: git-fixes
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/<driver>/unbind
DMA map object 0xffffff800b0ae540 still being held by &pdev->dev
~# echo soc:dummy >/sys/bus/platform/drivers/<driver>/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:
[<ffffffefd1694708>] create_object.isra.0+0x108/0x344
[<ffffffefd1d1a850>] kmemleak_alloc+0x8c/0xd0
[<ffffffefd167e2d0>] __kmalloc+0x440/0x6f0
[<ffffffefd1a960a4>] of_dma_get_range+0x124/0x220
[<ffffffefd1a8ce90>] of_dma_configure_id+0x40/0x2d0
[<ffffffefd198b68c>] platform_dma_configure+0x5c/0xa4
[<ffffffefd198846c>] really_probe+0x8c/0x514
[<ffffffefd1988990>] __driver_probe_device+0x9c/0x19c
[<ffffffefd1988cd8>] device_driver_attach+0x54/0xbc
[<ffffffefd1986634>] bind_store+0xc4/0x120
[<ffffffefd19856e0>] drv_attr_store+0x30/0x44
[<ffffffefd173c9b0>] sysfs_kf_write+0x50/0x60
[<ffffffefd173c1c4>] kernfs_fop_write_iter+0x124/0x1b4
[<ffffffefd16a013c>] new_sync_write+0xdc/0x160
[<ffffffefd16a256c>] vfs_write+0x23c/0x2a0
[<ffffffefd16a2758>] 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 <stable@vger.kernel.org>
Suggested-by: Rob Herring <robh@kernel.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Mårten Lindahl <marten.lindahl@axis.com>
Link: https://lore.kernel.org/r/20220216094128.4025861-1-marten.lindahl@axis.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
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 @@ static int really_probe(struct device *dev, struct device_driver *drv)
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)
--
2.31.1