[ 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@gmx.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- fs/char_dev.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/fs/char_dev.c b/fs/char_dev.c index 24b142569ca9b..d0655ca894816 100644 --- a/fs/char_dev.c +++ b/fs/char_dev.c @@ -130,6 +130,12 @@ __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;