Messages in this thread Patch in this message | | | Subject | [PATCH 1/2] char_dev: Fix off-by-one bugs in find_dynamic_major() | From | "Srivatsa S. Bhat" <> | Date | Mon, 05 Feb 2018 18:25:09 -0800 |
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From: Srivatsa S. Bhat <srivatsa@csail.mit.edu>
CHRDEV_MAJOR_DYN_END and CHRDEV_MAJOR_DYN_EXT_END are valid major numbers. So fix the loop iteration to include them in the search for free major numbers.
While at it, also remove a redundant if condition ("cd->major != i"), as it will never be true.
Signed-off-by: Srivatsa S. Bhat <srivatsa@csail.mit.edu> ---
fs/char_dev.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/fs/char_dev.c b/fs/char_dev.c index a65e4a5..33c9385 100644 --- a/fs/char_dev.c +++ b/fs/char_dev.c @@ -67,18 +67,18 @@ static int find_dynamic_major(void) int i; struct char_device_struct *cd; - for (i = ARRAY_SIZE(chrdevs)-1; i > CHRDEV_MAJOR_DYN_END; i--) { + for (i = ARRAY_SIZE(chrdevs)-1; i >= CHRDEV_MAJOR_DYN_END; i--) { if (chrdevs[i] == NULL) return i; } for (i = CHRDEV_MAJOR_DYN_EXT_START; - i > CHRDEV_MAJOR_DYN_EXT_END; i--) { + i >= CHRDEV_MAJOR_DYN_EXT_END; i--) { for (cd = chrdevs[major_to_index(i)]; cd; cd = cd->next) if (cd->major == i) break; - if (cd == NULL || cd->major != i) + if (cd == NULL) return i; }
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