On Mon, Nov 11, 2019 at 05:35:37PM -0800, coverity-bot wrote: > Hello! > > This is an experimental automated report about issues detected by Coverity > from a scan of next-20191108 as part of the linux-next weekly scan project: > https://scan.coverity.com/projects/linux-next-weekly-scan > > You're getting this email because you were associated with the identified > lines of code (noted below) that were touched by recent commits: > > c34aa3085f94 ("mm-vmscan-split-shrink_node-into-node-part-and-memcgs-part-fix") > > Coverity reported the following: > > *** CID 1487844: Null pointer dereferences (NULL_RETURNS) > /mm/vmscan.c: 2695 in shrink_node_memcgs() > 2689 memcg = mem_cgroup_iter(target_memcg, NULL, NULL); > 2690 do { > 2691 struct lruvec *lruvec = mem_cgroup_lruvec(memcg, pgdat); > 2692 unsigned long reclaimed; > 2693 unsigned long scanned; > 2694 > vvv CID 1487844: Null pointer dereferences (NULL_RETURNS) > vvv Dereferencing a pointer that might be "NULL" "memcg" when calling "mem_cgroup_protected". > 2695 switch (mem_cgroup_protected(target_memcg, memcg)) { This appears to be a false alarm. All the "culprit" patch did was rename the local variable "target_memcg". And while it's correct that memcg can be NULL (befor and after this patch), it's the case only when mem_cgroup_disabled(), and mem_cgroup_protected() checks for this case.
