[Devel] [PATCH hci-8.1 v2 3/4] shmem: reject the mpol= mount option in VE

From: Konstantin Khorenko <khorenko@virtuozzo.com>
To: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>,
	Vasileios Almpanis <vasileios.almpanis@virtuozzo.com>
Cc: devel@openvz.org
Subject: [Devel] [PATCH hci-8.1 v2 3/4] shmem: reject the mpol= mount option in VE
Date: Fri, 06 Nov 2026 15:01:34 +0100	[thread overview]
Message-ID: <20261106-b4-prep-khorenko-vstor-153679-mbind-ve-v2-3-6327b23a2d93@virtuozzo.com> (raw)
In-Reply-To: <20261106-b4-prep-khorenko-vstor-153679-mbind-ve-v2-0-6327b23a2d93@virtuozzo.com>

A CT is meant to see a kernel without NUMA support, so the NUMA API
syscalls return -ENOSYS in a non-super VE. The tmpfs mpol= mount option
still lets a CT set a NUMA memory policy for all files of a tmpfs
mount.

Reject mpol= in a non-super VE the way a kernel built without
CONFIG_NUMA does: the mount fails with -EINVAL and "Unsupported
parameter 'mpol'".

https://virtuozzo.atlassian.net/browse/VSTOR-153679

Feature: mm: prohibit NUMA API inside CT
Signed-off-by: Konstantin Khorenko <khorenko@virtuozzo.com>
---
 mm/shmem.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/shmem.c b/mm/shmem.c
index f8cea7e5de88d..8862723003fb0 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -4378,7 +4378,7 @@ static int shmem_parse_one(struct fs_context *fc, struct fs_parameter *param)
 		ctx->seen |= SHMEM_SEEN_HUGE;
 		break;
 	case Opt_mpol:
-		if (IS_ENABLED(CONFIG_NUMA)) {
+		if (IS_ENABLED(CONFIG_NUMA) && ve_is_super(get_exec_env())) {
 			mpol_put(ctx->mpol);
 			ctx->mpol = NULL;
 			if (mpol_parse_str(param->string, &ctx->mpol))

-- 
2.43.0

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