CVE-2020-36775: f2fs: fix to avoid potential deadlock

CVE-2020-36775: f2fs: fix to avoid potential deadlock

[Greg Kroah-Hartman]

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

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

f2fs: fix to avoid potential deadlock

Using f2fs_trylock_op() in f2fs_write_compressed_pages() to avoid potential
deadlock like we did in f2fs_write_single_data_page().

The Linux kernel CVE team has assigned CVE-2020-36775 to this issue.


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

	Fixed in 5.4.189 with commit 0478ccdc8ea0
	Fixed in 5.6.7 with commit 8e8542437bb4
	Fixed in 5.7 with commit df77fbd8c5b2

Please see https://www.kernel.org or 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-2020-36775
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/compress.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/0478ccdc8ea016de1ebaf6fe6da0275c2b258c5b
	https://git.kernel.org/stable/c/8e8542437bb4070423c9754d5ba270ffdbae8c8d
	https://git.kernel.org/stable/c/df77fbd8c5b222c680444801ffd20e8bbc90a56e