From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Wed, 2 Oct 2024 10:01:24 +0000 (+0200)
Subject: 5.15-stable patches
X-Git-Tag: v6.6.54~36
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4648f4ca4ab7a4302b605f74054db2059a2e8461;p=thirdparty%2Fkernel%2Fstable-queue.git

5.15-stable patches

added patches:
	io_uring-sqpoll-do-not-allow-pinning-outside-of-cpuset.patch
---

diff --git a/queue-5.15/io_uring-sqpoll-do-not-allow-pinning-outside-of-cpuset.patch b/queue-5.15/io_uring-sqpoll-do-not-allow-pinning-outside-of-cpuset.patch
new file mode 100644
index 00000000000..9f7cd044cdc
--- /dev/null
+++ b/queue-5.15/io_uring-sqpoll-do-not-allow-pinning-outside-of-cpuset.patch
@@ -0,0 +1,55 @@
+From 0ce44d871d55dc7067d6ef85553ba52510a04337 Mon Sep 17 00:00:00 2001
+From: Felix Moessbauer <felix.moessbauer@siemens.com>
+Date: Mon, 9 Sep 2024 17:00:36 +0200
+Subject: io_uring/sqpoll: do not allow pinning outside of cpuset
+
+From: Felix Moessbauer <felix.moessbauer@siemens.com>
+
+The submit queue polling threads are userland threads that just never
+exit to the userland. When creating the thread with IORING_SETUP_SQ_AFF,
+the affinity of the poller thread is set to the cpu specified in
+sq_thread_cpu. However, this CPU can be outside of the cpuset defined
+by the cgroup cpuset controller. This violates the rules defined by the
+cpuset controller and is a potential issue for realtime applications.
+
+In b7ed6d8ffd6 we fixed the default affinity of the poller thread, in
+case no explicit pinning is required by inheriting the one of the
+creating task. In case of explicit pinning, the check is more
+complicated, as also a cpu outside of the parent cpumask is allowed.
+We implemented this by using cpuset_cpus_allowed (that has support for
+cgroup cpusets) and testing if the requested cpu is in the set.
+
+Fixes: 37d1e2e3642e ("io_uring: move SQPOLL thread io-wq forked worker")
+Cc: stable@vger.kernel.org # 6.1+
+Signed-off-by: Felix Moessbauer <felix.moessbauer@siemens.com>
+Link: https://lore.kernel.org/r/20240909150036.55921-1-felix.moessbauer@siemens.com
+Signed-off-by: Jens Axboe <axboe@kernel.dk>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ io_uring/io_uring.c |    5 ++++-
+ 1 file changed, 4 insertions(+), 1 deletion(-)
+
+--- a/io_uring/io_uring.c
++++ b/io_uring/io_uring.c
+@@ -56,6 +56,7 @@
+ #include <linux/mm.h>
+ #include <linux/mman.h>
+ #include <linux/percpu.h>
++#include <linux/cpuset.h>
+ #include <linux/slab.h>
+ #include <linux/blkdev.h>
+ #include <linux/bvec.h>
+@@ -8746,10 +8747,12 @@ static int io_sq_offload_create(struct i
+ 			return 0;
+ 
+ 		if (p->flags & IORING_SETUP_SQ_AFF) {
++			struct cpumask allowed_mask;
+ 			int cpu = p->sq_thread_cpu;
+ 
+ 			ret = -EINVAL;
+-			if (cpu >= nr_cpu_ids || !cpu_online(cpu))
++			cpuset_cpus_allowed(current, &allowed_mask);
++			if (!cpumask_test_cpu(cpu, &allowed_mask))
+ 				goto err_sqpoll;
+ 			sqd->sq_cpu = cpu;
+ 		} else {
diff --git a/queue-5.15/series b/queue-5.15/series
index dd50f033997..b8aec8056ba 100644
--- a/queue-5.15/series
+++ b/queue-5.15/series
@@ -352,3 +352,4 @@ pps-remove-usage-of-the-deprecated-ida_simple_xx-api.patch
 pps-add-an-error-check-in-parport_attach.patch
 x86-idtentry-incorporate-definitions-declarations-of.patch
 x86-entry-remove-unwanted-instrumentation-in-common_.patch
+io_uring-sqpoll-do-not-allow-pinning-outside-of-cpuset.patch