mmc: block: Ensure that debugfs files are removed

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commit f9f0da9881 upstream.

The card is not necessarily being removed, but the debugfs files must be
removed when the driver is removed, otherwise they will continue to exist
after unbinding the card from the driver. e.g.

  # echo "mmc1:0001" > /sys/bus/mmc/drivers/mmcblk/unbind
  # cat /sys/kernel/debug/mmc1/mmc1\:0001/ext_csd
  [  173.634584] BUG: unable to handle kernel NULL pointer dereference at 0000000000000050
  [  173.643356] IP: mmc_ext_csd_open+0x5e/0x170

A complication is that the debugfs_root may have already been removed, so
check for that too.

Fixes: 627c3ccfb4 ("mmc: debugfs: Move block debugfs into block module")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

This commit is contained in:

Adrian Hunter 2017-11-21 15:42:30 +02:00 • committed by Greg Kroah-Hartman

parent 94497458fb

commit 64d1df6f01

2 changed files with 38 additions and 7 deletions

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44

drivers/mmc/core/block.c

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1

drivers/mmc/core/debugfs.c

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