CVE-2026-74362: ext2: fix ignored return value of generic_write_sync()

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

From: Greg Kroah-Hartman <gregkh@kernel.org>

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

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

ext2: fix ignored return value of generic_write_sync()

Fix ext2_dio_write_iter() to propagate the error returned by
generic_write_sync() instead of silently discarding it, which could
cause write(2) to return success to userspace on O_SYNC/O_DSYNC files
even when the sync failed.

The correct pattern, already used in ext2_dax_write_iter() in the same
file and in ext4, xfs, f2fs among others, is:
    if (ret > 0)
        ret = generic_write_sync(iocb, ret);

Found by Linux Verification Center (linuxtesting.org) with SVACE.

[JK: Reflect also filemap_write_and_wait() return value]

The Linux kernel CVE team has assigned CVE-2026-74362 to this issue.


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

	Issue introduced in 6.5 with commit fb5de4358e1aa4753dce73c4dc1aca73ff39cedd and fixed in 6.6.145 with commit 8990dbb7065b0b002b1e58b9091a5b61f5e94dbe
	Issue introduced in 6.5 with commit fb5de4358e1aa4753dce73c4dc1aca73ff39cedd and fixed in 6.12.97 with commit 8d70b3973020e59845c0bdad90e0b9c2295fd493
	Issue introduced in 6.5 with commit fb5de4358e1aa4753dce73c4dc1aca73ff39cedd and fixed in 6.18.40 with commit ffa974b2f50ad8b911b9066d7aed84ad0afabcdb
	Issue introduced in 6.5 with commit fb5de4358e1aa4753dce73c4dc1aca73ff39cedd and fixed in 7.1.5 with commit b6bc07e49a5fbb335f56eb90cd63dec6584c77d3
	Issue introduced in 6.5 with commit fb5de4358e1aa4753dce73c4dc1aca73ff39cedd and fixed in 7.2-rc1 with commit a4659be0bc7cb1856ffb15b67f903229ae8891ec

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-2026-74362
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/ext2/file.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/8990dbb7065b0b002b1e58b9091a5b61f5e94dbe
	https://git.kernel.org/stable/c/8d70b3973020e59845c0bdad90e0b9c2295fd493
	https://git.kernel.org/stable/c/ffa974b2f50ad8b911b9066d7aed84ad0afabcdb
	https://git.kernel.org/stable/c/b6bc07e49a5fbb335f56eb90cd63dec6584c77d3
	https://git.kernel.org/stable/c/a4659be0bc7cb1856ffb15b67f903229ae8891ec