Subject: CVE-2024-50060: io_uring: check if we need to reschedule during overflow flush

From: Greg Kroah-Hartman <[email-masked]>

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

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

io_uring: check if we need to reschedule during overflow flush

In terms of normal application usage, this list will always be empty.
And if an application does overflow a bit, it'll have a few entries.
However, nothing obviously prevents syzbot from running a test case
that generates a ton of overflow entries, and then flushing them can
take quite a while.

Check for needing to reschedule while flushing, and drop our locks and
do so if necessary. There's no state to maintain here as overflows
always prune from head-of-list, hence it's fine to drop and reacquire
the locks at the end of the loop.

The Linux kernel CVE team has assigned CVE-2024-50060 to this issue.

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

	Fixed in 6.1.113 with commit a2493904e95c
	Fixed in 6.6.57 with commit f4ce3b5d26ce
	Fixed in 6.11.4 with commit c2eadeafce2d
	Fixed in 6.12-rc1 with commit eac2ca2d682f

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-2024-50060
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:
	io_uring/io_uring.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/a2493904e95ce94bbec819d8f7f03b99976eb25c
	https://git.kernel.org/stable/c/f4ce3b5d26ce149e77e6b8e8f2058aa80e5b034e
	https://git.kernel.org/stable/c/c2eadeafce2d385b3f6d26a7f31fee5aba2bbbb0
	https://git.kernel.org/stable/c/eac2ca2d682f94f46b1973bdf5e77d85d77b8e53