If unallocated_id = (ANY * idr_max(idp->layers) + existed_id) is passed
to idr_remove(). The existed_id will be removed unexpected.
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");
}
It only happens when unallocated_id, it is caller's fault. It is not
a bug. But it is better to add the proper check and complains instead
of removing an existed_id silently.
Signed-off-by: Lai Jiangshan <la...@cn.fujitsu.com>
---
lib/idr.c | 5 +++++
1 files changed, 5 insertions(+), 0 deletions(-)
diff --git a/lib/idr.c b/lib/idr.c
index 4df6792..a28036d 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]) {
--
1.7.4.4
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