Hi,
Static analysis with Coverity on linux-next picked up a potential issue
with the following commit:
commit 035087b3c256741be367747eab866505cece31fb
Author: Qu Wenruo <w...@suse.com>
Date: Sat Aug 3 14:45:59 2019 +0800
btrfs: qgroup: Try our best to delete qgroup relations
The static analysis report is as follows:
1334 */
3. Condition !member, taking true branch.
4. var_compare_op: Comparing member to null implies that member
might be null.
5. Condition !parent, taking false branch.
1335 if (!member && !parent)
1336 goto delete_item;
1337
1338 /* check if such qgroup relation exist firstly */
CID 85026 (#1 of 1): Dereference after null check (FORWARD_NULL)
6. var_deref_op: Dereferencing null pointer member.
1339 list_for_each_entry(list, &member->groups, next_group) {
1340 if (list->group == parent) {
1341 found = true;
1342 break;
1343 }
1344 }
An example of the issue that if member is NULL and parent is not null
then the list_for_each_entry loop with dereference the NULL member
pointer. The changed logic in the patch on line 1335 is the root cause
of this regression. I believe it should still be:
if (!member && !parent)
goto delete_item;
Colin
