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authorLai Jiangshan <laijs@cn.fujitsu.com>2014-06-06 21:37:11 (GMT)
committerLinus Torvalds <torvalds@linux-foundation.org>2014-06-06 23:08:12 (GMT)
commit8f9f665a707721146f24a892b1a0da1ab4da1d58 (patch)
tree75850b4a284ac671b7f1b563c985b959181aa70d /lib/idr.c
parent3afb69cb5572b3c8c898c00880803cf1a49852c4 (diff)
idr: fix unexpected ID-removal when idr_remove(unallocated_id)
If unallocated_id = (ANY * idr_max(idp->layers) + existing_id) is passed to idr_remove(). The existing_id will be removed unexpectedly. The following test shows this unexpected id-removal: static void test4(void) { int id; DEFINE_IDR(test_idr); printk(KERN_INFO "Start test4\n"); id = idr_alloc(&test_idr, (void *)1, 42, 43, GFP_KERNEL); BUG_ON(id != 42); idr_remove(&test_idr, 42 + IDR_SIZE); TEST_BUG_ON(idr_find(&test_idr, 42) != (void *)1); idr_destroy(&test_idr); printk(KERN_INFO "End of test4\n"); } ida_remove() shares the similar problem. It happens only when the caller tries to free an unallocated ID which is the caller's fault. It is not a bug. But it is better to add the proper check and complain rather than removing an existing_id silently. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib/idr.c')
-rw-r--r--lib/idr.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/lib/idr.c b/lib/idr.c
index 4df6792..c4afd94 100644
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -562,6 +562,11 @@ void idr_remove(struct idr *idp, int id)
if (id < 0)
return;
+ if (id > idr_max(idp->layers)) {
+ idr_remove_warning(id);
+ return;
+ }
+
sub_remove(idp, (idp->layers - 1) * IDR_BITS, id);
if (idp->top && idp->top->count == 1 && (idp->layers > 1) &&
idp->top->ary[0]) {
@@ -1025,6 +1030,9 @@ void ida_remove(struct ida *ida, int id)
int n;
struct ida_bitmap *bitmap;
+ if (idr_id > idr_max(ida->idr.layers))
+ goto err;
+
/* clear full bits while looking up the leaf idr_layer */
while ((shift > 0) && p) {
n = (idr_id >> shift) & IDR_MASK;

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