CVE-2024-41935: f2fs: fix to shrink read extent node in batches

CVE-2024-41935: f2fs: fix to shrink read extent node in batches

[Greg Kroah-Hartman]

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

f2fs: fix to shrink read extent node in batches

We use rwlock to protect core structure data of extent tree during
its shrink, however, if there is a huge number of extent nodes in
extent tree, during shrink of extent tree, it may hold rwlock for
a very long time, which may trigger kernel hang issue.

This patch fixes to shrink read extent node in batches, so that,
critical region of the rwlock can be shrunk to avoid its extreme
long time hold.

The Linux kernel CVE team has assigned CVE-2024-41935 to this issue.


Affected and fixed versions
===========================

	Fixed in 6.6.66 with commit 295b50e95e900da31ff237e46e04525fa799b2cf
	Fixed in 6.12.5 with commit 924f7dd1e832e4e4530d14711db223d2803f7b61
	Fixed in 6.13-rc1 with commit 3fc5d5a182f6a1f8bd4dc775feb54c369dd2c343

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2024-41935
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	fs/f2fs/extent_cache.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/295b50e95e900da31ff237e46e04525fa799b2cf
	https://git.kernel.org/stable/c/924f7dd1e832e4e4530d14711db223d2803f7b61
	https://git.kernel.org/stable/c/3fc5d5a182f6a1f8bd4dc775feb54c369dd2c343