releases/4.19.31/clk-samsung-exynos5-fix-kfree-of-const-memory-on-setting-driver_override.patch

   1 From 785c9f411eb2d9a6076d3511c631587d5e676bf3 Mon Sep 17 00:00:00 2001
   2 From: Krzysztof Kozlowski <krzk@kernel.org>
   3 Date: Thu, 21 Feb 2019 12:45:52 +0100
   4 Subject: clk: samsung: exynos5: Fix kfree() of const memory on setting driver_override
   5
   6 From: Krzysztof Kozlowski <krzk@kernel.org>
   7
   8 commit 785c9f411eb2d9a6076d3511c631587d5e676bf3 upstream.
   9
  10 Platform driver driver_override field should not be initialized from
  11 const memory because the core later kfree() it.  If driver_override is
  12 manually set later through sysfs, kfree() of old value leads to:
  13
  14     $ echo "new_value" > /sys/bus/platform/drivers/.../driver_override
  15
  16     kernel BUG at ../mm/slub.c:3960!
  17     Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM
  18     ...
  19     (kfree) from [<c058e8c0>] (platform_set_driver_override+0x84/0xac)
  20     (platform_set_driver_override) from [<c058e908>] (driver_override_store+0x20/0x34)
  21     (driver_override_store) from [<c031f778>] (kernfs_fop_write+0x100/0x1dc)
  22     (kernfs_fop_write) from [<c0296de8>] (__vfs_write+0x2c/0x17c)
  23     (__vfs_write) from [<c02970c4>] (vfs_write+0xa4/0x188)
  24     (vfs_write) from [<c02972e8>] (ksys_write+0x4c/0xac)
  25     (ksys_write) from [<c0101000>] (ret_fast_syscall+0x0/0x28)
  26
  27 The clk-exynos5-subcmu driver uses override only for the purpose of
  28 creating meaningful names for children devices (matching names of power
  29 domains, e.g. DISP, MFC).  The driver_override was not developed for
  30 this purpose so just switch to default names of devices to fix the
  31 issue.
  32
  33 Fixes: b06a532bf1fa ("clk: samsung: Add Exynos5 sub-CMU clock driver")
  34 Cc: <stable@vger.kernel.org>
  35 Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
  36 Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
  37 Signed-off-by: Stephen Boyd <sboyd@kernel.org>
  38 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  39
  40 ---
  41  drivers/clk/samsung/clk-exynos5-subcmu.c |    3 +--
  42  1 file changed, 1 insertion(+), 2 deletions(-)
  43
  44 --- a/drivers/clk/samsung/clk-exynos5-subcmu.c
  45 +++ b/drivers/clk/samsung/clk-exynos5-subcmu.c
  46 @@ -138,12 +138,11 @@ static int __init exynos5_clk_register_s
  47         struct platform_device *pdev;
  48         int ret;
  49
  50 -       pdev = platform_device_alloc(info->pd_name, -1);
  51 +       pdev = platform_device_alloc("exynos5-subcmu", PLATFORM_DEVID_AUTO);
  52         if (!pdev)
  53                 return -ENOMEM;
  54
  55         pdev->dev.parent = parent;
  56 -       pdev->driver_override = "exynos5-subcmu";
  57         platform_set_drvdata(pdev, (void *)info);
  58         of_genpd_add_device(&genpdspec, &pdev->dev);
  59         ret = platform_device_add(pdev);