682886ec69
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
Link: https://lkml.kernel.org/r/20240418124043.GC1055428@cmpxchg.org
Link: https://lkml.kernel.org/r/20240417143324.GA1055428@cmpxchg.org
Fixes:
|
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.