| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.19 210/276] chardev: add additional check for minor range overlap | Date | Wed, 29 May 2019 20:06:08 -0700 |
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[ 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 a279c58fe3606..8a63cfa290053 100644 --- a/fs/char_dev.c +++ b/fs/char_dev.c @@ -159,6 +159,12 @@ __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
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