[ Upstream commit de36e16d1557a0b6eb328bc3516359a12ba5c25c ]
Current overlap checking cannot correctly handle
a case which is baseminor < existing baseminor &&
baseminor + minorct > existing baseminor + minorct.
Signed-off-by: Chengguang Xu <cgxu519@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
fs/char_dev.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/fs/char_dev.c b/fs/char_dev.c
index 44a240c4bb658..a112a4745d8b3 100644
--- a/fs/char_dev.c
+++ b/fs/char_dev.c
@@ -134,6 +134,12 @@ __register_chrdev_region(unsigned int major, unsigned int baseminor,
ret = -EBUSY;
goto out;
}
+
+ if (new_min < old_min && new_max > old_max) {
+ ret = -EBUSY;
+ goto out;
+ }
+
}
cd->next = *cp;
--
2.20.1
