The patch titled
Chardev checking of overlapping ranges
has been removed from the -mm tree. Its filename is
chardev-checking-of-overlapping-ranges.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
Subject: Chardev checking of overlapping ranges
From: Amos Waterland <apw@xxxxxxxxxx>
The code in __register_chrdev_region checks that if the driver wishing to
register has the same major as an existing driver the new minor range is
strictly less than the existing minor range. However, it does not also
check that the new minor range is strictly greater than the existing minor
range. That is, if driver X has registered with major=x and minor=0-3,
__register_chrdev_region will allow driver Y to register with major=x and
minor=1-4.
Signed-off-by: Amos Waterland <apw@xxxxxxxxxx>
Cc: Linas Vepstas <linas@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
fs/char_dev.c | 28 +++++++++++++++++++++++-----
1 file changed, 23 insertions(+), 5 deletions(-)
diff -puN fs/char_dev.c~chardev-checking-of-overlapping-ranges fs/char_dev.c
--- a/fs/char_dev.c~chardev-checking-of-overlapping-ranges
+++ a/fs/char_dev.c
@@ -128,13 +128,31 @@ __register_chrdev_region(unsigned int ma
for (cp = &chrdevs[i]; *cp; cp = &(*cp)->next)
if ((*cp)->major > major ||
- ((*cp)->major == major && (*cp)->baseminor >= baseminor))
+ ((*cp)->major == major &&
+ (((*cp)->baseminor >= baseminor) ||
+ ((*cp)->baseminor + (*cp)->minorct > baseminor))))
break;
- if (*cp && (*cp)->major == major &&
- (*cp)->baseminor < baseminor + minorct) {
- ret = -EBUSY;
- goto out;
+
+ /* Check for overlapping minor ranges. */
+ if (*cp && (*cp)->major == major) {
+ int old_min = (*cp)->baseminor;
+ int old_max = (*cp)->baseminor + (*cp)->minorct - 1;
+ int new_min = baseminor;
+ int new_max = baseminor + minorct - 1;
+
+ /* New driver overlaps from the left. */
+ if (new_max >= old_min && new_max <= old_max) {
+ ret = -EBUSY;
+ goto out;
+ }
+
+ /* New driver overlaps from the right. */
+ if (new_min <= old_max && new_min >= old_min) {
+ ret = -EBUSY;
+ goto out;
+ }
}
+
cd->next = *cp;
*cp = cd;
mutex_unlock(&chrdevs_lock);
_
Patches currently in -mm which might be from apw@xxxxxxxxxx are
origin.patch
-
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