[Devel] [PATCH RHEL10 COMMIT] ms/libfs: set SB_I_NOEXEC and SB_I_NODEV by default in init_pseudo()

[Konstantin Khorenko]

The commit is pushed to "branch-rh10-6.12.0-211.39.1.16.x.vz10-ovz" and will appear at git at bitbucket.org:openvz/vzkernel.git
after rh10-6.12.0-211.39.1.16.1.vz10
------>
commit 1e3139652d06687cabb644e7449a9549dcec4b42
Author: John Hubbard <jhubbard at nvidia.com>
Date:   Mon Jul 27 14:22:49 2026 +0200

    ms/libfs: set SB_I_NOEXEC and SB_I_NODEV by default in init_pseudo()
    
    Since commit 1e7ab6f67824 ("anon_inode: rework assertions"),
    path_noexec() warns when an anonymous-inode file is mmap'd from a
    superblock that has not set SB_I_NOEXEC. dma-buf backs its files this
    way and never set the flag, so mmap of any exported buffer trips the
    warning on a CONFIG_DEBUG_VFS=y kernel:
    
      WARNING: CPU: 11 PID: 121813 at fs/exec.c:118 path_noexec+0x47/0x50
       do_mmap+0x2b5/0x680
       vm_mmap_pgoff+0x129/0x210
       ksys_mmap_pgoff+0x177/0x240
       __x64_sys_mmap+0x33/0x70
    
    init_pseudo() sets up internal SB_NOUSER mounts that are never
    path-reachable. Set both flags here so every pseudo filesystem gets
    them by default instead of each caller setting them.
    
    SB_I_NODEV is inert for unreachable mounts. SB_I_NOEXEC has one
    visible effect: an executable mapping of a pseudo-fs fd, such as a
    dma-buf, now fails with -EPERM, which is the invariant the assertion
    enforces. No in-tree caller maps these executable.
    
    Reproduce on CONFIG_DEBUG_VFS=y:
    
      make -C tools/testing/selftests/dmabuf-heaps
      sudo ./tools/testing/selftests/dmabuf-heaps/dmabuf-heap -t system
    
    Fixes: 1e7ab6f67824 ("anon_inode: rework assertions")
    Suggested-by: Christoph Hellwig <hch at infradead.org>
    Cc: stable at vger.kernel.org
    Signed-off-by: John Hubbard <jhubbard at nvidia.com>
    Link: https://patch.msgid.link/20260604025315.245910-2-jhubbard@nvidia.com
    Signed-off-by: Christian Brauner (Amutable) <brauner at kernel.org>
    
    (cherry picked from commit 6de2aeffabaafaeda819e60ec8d04f199711e11a)
    Feature: ve: CRIU support
    https://virtuozzo.atlassian.net/browse/VSTOR-139264
    Signed-off-by: Pavel Tikhomirov <ptikhomirov at virtuozzo.com>
    Reviewed-by: Vasileios Almpanis <vasileios.almpanis at virtuozzo.com>
    Reviewed-by: Vladimir Riabchun <vladimir.riabchun at virtuozzo.com>
---
 fs/libfs.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/libfs.c b/fs/libfs.c
index af191a388303c..17a0a4d9bfe8b 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -721,6 +721,7 @@ struct pseudo_fs_context *init_pseudo(struct fs_context *fc,
 		fc->fs_private = ctx;
 		fc->ops = &pseudo_fs_context_ops;
 		fc->sb_flags |= SB_NOUSER;
+		fc->s_iflags |= SB_I_NOEXEC | SB_I_NODEV;
 		fc->global = true;
 	}
 	return ctx;