1.3 KiB
CVE-2024-35846
Description
In the Linux kernel, the following vulnerability has been resolved:mm: zswap: fix shrinker NULL crash with cgroup_disable=memoryChristian reports a NULL deref in zswap that he bisected down to the zswapshrinker. The issue also cropped up in the bug trackers of libguestfs [1]and the Red Hat bugzilla [2].The problem is that when memcg is disabled with the boot time flag, thezswap shrinker might get called with sc->memcg == NULL. This is okay inmany places, like the lruvec operations. But it crashes inmemcg_page_state() - which is only used due to the non-node accounting ofcgroup's the zswap memory to begin with.Nhat spotted that the memcg can be NULL in the memcg-disabled case, and Iwas then able to reproduce the crash locally as well.[1] https://github.com/libguestfs/libguestfs/issues/139[2] https://bugzilla.redhat.com/show_bug.cgi?id=2275252
POC
Reference
No PoCs from references.