Subject: + idr-fix-unexpected-id-removal-when-idr_removeunallocated_id.patch added to -mm tree
To: laijs@xxxxxxxxxxxxxx,tj@xxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Tue, 22 Apr 2014 12:40:44 -0700
The patch titled
Subject: idr: fix unexpected ID-removal when idr_remove(unallocated_id)
has been added to the -mm tree. Its filename is
idr-fix-unexpected-id-removal-when-idr_removeunallocated_id.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/idr-fix-unexpected-id-removal-when-idr_removeunallocated_id.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/idr-fix-unexpected-id-removal-when-idr_removeunallocated_id.patch
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------------------------------------------------------
From: Lai Jiangshan <laijs@xxxxxxxxxxxxxx>
Subject: 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@xxxxxxxxxxxxxx>
Acked-by: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/idr.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff -puN lib/idr.c~idr-fix-unexpected-id-removal-when-idr_removeunallocated_id lib/idr.c
--- a/lib/idr.c~idr-fix-unexpected-id-removal-when-idr_removeunallocated_id
+++ a/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;
_
Patches currently in -mm which might be from laijs@xxxxxxxxxxxxxx are
mem-hotplug-implement-get-put_online_mems.patch
slab-get_online_mems-for-kmem_cache_createdestroyshrink.patch
idr-fix-overflow-bug-during-maximum-id-calculation-at-maximum-height.patch
idr-fix-unexpected-id-removal-when-idr_removeunallocated_id.patch
idr-fix-null-pointer-dereference-when-ida_removeunallocated_id.patch
idr-fix-idr_replaces-returned-error-code.patch
idr-dont-need-to-shink-the-free-list-when-idr_remove.patch
idr-reduce-the-unneeded-check-in-free_layer.patch
linux-next.patch
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