dm_get_device() is paired with dm_put_device(), and needs to
always increase the refcount. Otherwise the device will be released
and we get a nice use-after-free kernel oops.
Fixes: 2a0b4682e09d ("dm: convert dm_dev_internal.count from atomic_t to
refcount_t)
Cc: Elena Reshetova <[email protected]>
Signed-off-by: Hannes Reinecke <[email protected]>
---
drivers/md/dm-table.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 88130b5d95f9..1f5d6922a1fc 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -450,14 +450,15 @@ int dm_get_device(struct dm_target *ti, const char *path,
fmode_t mode,
kfree(dd);
return r;
}
-
refcount_set(&dd->count, 1);
list_add(&dd->list, &t->devices);
- } else if (dd->dm_dev->mode != (mode | dd->dm_dev->mode)) {
- r = upgrade_mode(dd, mode, t->md);
- if (r)
- return r;
+ } else {
+ if (dd->dm_dev->mode != (mode | dd->dm_dev->mode)) {
+ r = upgrade_mode(dd, mode, t->md);
+ if (r)
+ return r;
+ }
refcount_inc(&dd->count);
}
--
2.12.3
--
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