mm: zswap: fix shrinker NULL crash with cgroup_disable=memory
Christian reports a NULL deref in zswap that he bisected down to the zswap
shrinker. 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, the
zswap shrinker might get called with sc->memcg == NULL. This is okay in
many places, like the lruvec operations. But it crashes in
memcg_page_state() - which is only used due to the non-node accounting of
cgroup's the zswap memory to begin with.
Nhat spotted that the memcg can be NULL in the memcg-disabled case, and I
was 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
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Tracking
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| Source | ID | Title |
|---|---|---|
Ubuntu USN |
USN-6949-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-6949-2 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-6952-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-6955-1 | Linux kernel (OEM) vulnerabilities |
Mon, 30 Dec 2024 18:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Linux
Linux linux Kernel |
|
| Weaknesses | CWE-476 | |
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.9:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.9:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.9:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.9:rc4:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.9:rc5:*:*:*:*:*:* |
|
| Vendors & Products |
Linux
Linux linux Kernel |
Wed, 06 Nov 2024 08:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
|
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-05-11T20:12:16.353Z
Reserved: 2024-05-17T13:50:33.105Z
Link: CVE-2024-35846
Updated: 2024-08-02T03:21:48.525Z
Status : Analyzed
Published: 2024-05-17T15:15:21.547
Modified: 2024-12-30T17:39:04.807
Link: CVE-2024-35846
OpenCVE Enrichment
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Ubuntu USN