[PATCH 26/52] mmc_block: add dev_t initialization check

[Greg Kroah-Hartman]

From: Anna Lemehova <EXT-Anna.Lemehova@xxxxxxxxx>

commit 7d92df692994472cab6045bbd9d0e2c4afa4365f upstream.

When a card is removed before mmc_blk_probe() has called add_disk(), then
the minor field is uninitialized and has value 0.  This caused
mmc_blk_put() to always release devidx 0 even if 0 was still in use.  Then
the next mmc_blk_probe() used the first free idx of 0, which oopses in
sysfs, since it is used by another card.

Signed-off-by: Anna Lemehova <EXT-Anna.Lemehova@xxxxxxxxx>
Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: <linux-mmc@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
 drivers/mmc/card/block.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index 85f0e8c..5988573 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -85,7 +85,12 @@ static void mmc_blk_put(struct mmc_blk_data *md)
 	mutex_lock(&open_lock);
 	md->usage--;
 	if (md->usage == 0) {
+		int devmaj = MAJOR(disk_devt(md->disk));
 		int devidx = MINOR(disk_devt(md->disk)) >> MMC_SHIFT;
+
+		if (!devmaj)
+			devidx = md->disk->first_minor >> MMC_SHIFT;
+
 		__clear_bit(devidx, dev_use);
 
 		put_disk(md->disk);
-- 
1.6.6

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