Subject: CVE-2024-38576: rcu: Fix buffer overflow in print_cpu_stall_info()

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

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

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

rcu: Fix buffer overflow in print_cpu_stall_info()

The rcuc-starvation output from print_cpu_stall_info() might overflow the
buffer if there is a huge difference in jiffies difference.  The situation
might seem improbable, but computers sometimes get very confused about
time, which can result in full-sized integers, and, in this case,
buffer overflow.

Also, the unsigned jiffies difference is printed using %ld, which is
normally for signed integers.  This is intentional for debugging purposes,
but it is not obvious from the code.

This commit therefore changes sprintf() to snprintf() and adds a
clarifying comment about intention of %ld format.

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

The Linux kernel CVE team has assigned CVE-2024-38576 to this issue.

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

	Issue introduced in 6.0 with commit 245a62982502 and fixed in 6.1.93 with commit e2228ed3fe7a
	Issue introduced in 6.0 with commit 245a62982502 and fixed in 6.6.33 with commit afb39909bfb5
	Issue introduced in 6.0 with commit 245a62982502 and fixed in 6.8.12 with commit 9351e1338539
	Issue introduced in 6.0 with commit 245a62982502 and fixed in 6.9.3 with commit 4c3e2ef4d8dd
	Issue introduced in 6.0 with commit 245a62982502 and fixed in 6.10 with commit 3758f7d9917b

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-2024-38576
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:
	kernel/rcu/tree_stall.h

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/e2228ed3fe7aa838fba87c79a76fb1ad9ea47138
	https://git.kernel.org/stable/c/afb39909bfb5c08111f99e21bf5be7505f59ff1c
	https://git.kernel.org/stable/c/9351e1338539cb7f319ffc1210fa9b2aa27384b5
	https://git.kernel.org/stable/c/4c3e2ef4d8ddd313c8ce3ac30505940bea8d6257
	https://git.kernel.org/stable/c/3758f7d9917bd7ef0482c4184c0ad673b4c4e069