releases/4.16.4/mmc-core-prevent-bus-reference-leak-in-mmc_blk_init.patch

   1 From d0a0852b9f81cf5f793bf2eae7336ed40a1a1815 Mon Sep 17 00:00:00 2001
   2 From: Alexander Kappner <agk@godking.net>
   3 Date: Wed, 28 Mar 2018 15:18:31 -0700
   4 Subject: mmc: core: Prevent bus reference leak in mmc_blk_init()
   5
   6 From: Alexander Kappner <agk@godking.net>
   7
   8 commit d0a0852b9f81cf5f793bf2eae7336ed40a1a1815 upstream.
   9
  10 Upon module load, mmc_block allocates a bus with bus_registeri() in
  11 mmc_blk_init(). This reference never gets freed during module unload, which
  12 leads to subsequent re-insertions of the module fails and a WARN() splat is
  13 triggered.
  14
  15 Fix the bug by dropping the reference for the bus in mmc_blk_exit().
  16
  17 Signed-off-by: Alexander Kappner <agk@godking.net>
  18 Fixes: 97548575bef3 ("mmc: block: Convert RPMB to a character device")
  19 Cc: <stable@vger.kernel.org>
  20 Reviewed-by: Shawn Lin <shawn.lin@rock-chips.com>
  21 Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
  22 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  23
  24 ---
  25  drivers/mmc/core/block.c |    1 +
  26  1 file changed, 1 insertion(+)
  27
  28 --- a/drivers/mmc/core/block.c
  29 +++ b/drivers/mmc/core/block.c
  30 @@ -3087,6 +3087,7 @@ static void __exit mmc_blk_exit(void)
  31         mmc_unregister_driver(&mmc_driver);
  32         unregister_blkdev(MMC_BLOCK_MAJOR, "mmc");
  33         unregister_chrdev_region(mmc_rpmb_devt, MAX_DEVICES);
  34 +       bus_unregister(&mmc_rpmb_bus_type);
  35  }
  36
  37  module_init(mmc_blk_init);