Merge patch series "libfs: set SB_I_NOEXEC and SB_I_NODEV in init_pseudo()"

John Hubbard <jhubbard@nvidia.com> says:

This began as a one-line dma-buf fix for a path_noexec() warning added
by commit 1e7ab6f67824 ("anon_inode: rework assertions"). Christoph
pointed out that the fix belongs higher up: a pseudo filesystem has no
reason not to set SB_I_NOEXEC by default. This series does that.

  * Patch 1 sets both flags in init_pseudo(), so every pseudo
    filesystem gets them. This is the only patch that changes a flag,
    and the only one with Fixes:/Cc: stable.

  * Patch 2 drops the assignments that are now redundant in the callers
    that set them by hand.

Most callers already set one or both flags. I audited every
init_pseudo() caller. Here is what patch 1 actually changes for each.
The only visible effect is on dma-buf, where SB_I_NOEXEC silences the
warning. SB_I_NODEV is never consulted on these SB_NOUSER mounts, and
none of the callers that gain SB_I_NOEXEC are executed from.

  caller                       had        patch 1 adds
  ---------------------------  --------   --------------
  fs/anon_inodes.c             both       nothing new
  mm/secretmem.c               both       nothing new
  virt/kvm/guest_memfd.c       both       nothing new
  fs/nsfs.c                    both       nothing new
  fs/pidfs.c                   both       nothing new
  fs/aio.c                     NOEXEC     NODEV
  drivers/dma-buf/dma-buf.c    neither    NOEXEC + NODEV
  net/socket.c                 neither    NOEXEC + NODEV
  fs/pipe.c                    neither    NOEXEC + NODEV
  kernel/resource.c            neither    NOEXEC + NODEV
  fs/erofs/super.c             neither    NOEXEC + NODEV
  fs/btrfs/tests/...           neither    NOEXEC + NODEV
  drivers/vfio/vfio_main.c     neither    NOEXEC + NODEV
  drivers/gpu/drm/drm_drv.c    neither    NOEXEC + NODEV
  drivers/dax/super.c          neither    NOEXEC + NODEV
  block/bdev.c                 neither    NOEXEC + NODEV

* patches from https://patch.msgid.link/20260604025315.245910-1-jhubbard@nvidia.com:
  libfs: drop redundant SB_I_NOEXEC/SB_I_NODEV in init_pseudo() callers
  libfs: set SB_I_NOEXEC and SB_I_NODEV by default in init_pseudo()

Link: https://patch.msgid.link/20260604025315.245910-1-jhubbard@nvidia.com
Signed-off-by: Christian Brauner <brauner@kernel.org>

7 files changed, 1 insertions, 10 deletions

diff --git a/fs/aio.c b/fs/aio.c
index 722476560848..f57fa21a2503 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -318,7 +318,6 @@ static int aio_init_fs_context(struct fs_context *fc)
 	pfc = init_pseudo(fc, AIO_RING_MAGIC);
 	if (!pfc)
 		return -ENOMEM;
-	fc->s_iflags |= SB_I_NOEXEC;
 	pfc->ops = &aio_super_operations;
 	return 0;
 }
diff --git a/fs/anon_inodes.c b/fs/anon_inodes.c
index b8381c7fb636..a7b9b948e33d 100644
--- a/fs/anon_inodes.c
+++ b/fs/anon_inodes.c
@@ -86,8 +86,6 @@ static int anon_inodefs_init_fs_context(struct fs_context *fc)
 	struct pseudo_fs_context *ctx = init_pseudo(fc, ANON_INODE_FS_MAGIC);
 	if (!ctx)
 		return -ENOMEM;
-	fc->s_iflags |= SB_I_NOEXEC;
-	fc->s_iflags |= SB_I_NODEV;
 	ctx->dops = &anon_inodefs_dentry_operations;
 	return 0;
 }
diff --git a/fs/libfs.c b/fs/libfs.c
index 80a330c8296f..124139645f7f 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -736,6 +736,7 @@ 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;
diff --git a/fs/nsfs.c b/fs/nsfs.c
index 51e8c9430477..c43c127cc035 100644
--- a/fs/nsfs.c
+++ b/fs/nsfs.c
@@ -664,7 +664,6 @@ static int nsfs_init_fs_context(struct fs_context *fc)
 	struct pseudo_fs_context *ctx = init_pseudo(fc, NSFS_MAGIC);
 	if (!ctx)
 		return -ENOMEM;
-	fc->s_iflags |= SB_I_NOEXEC | SB_I_NODEV;
 	ctx->s_d_flags |= DCACHE_DONTCACHE;
 	ctx->ops = &nsfs_ops;
 	ctx->eops = &nsfs_export_operations;
diff --git a/fs/pidfs.c b/fs/pidfs.c
index 1cce4f34a051..c363416766f1 100644
--- a/fs/pidfs.c
+++ b/fs/pidfs.c
@@ -1115,8 +1115,6 @@ static int pidfs_init_fs_context(struct fs_context *fc)
 	if (!ctx)
 		return -ENOMEM;
 
-	fc->s_iflags |= SB_I_NOEXEC;
-	fc->s_iflags |= SB_I_NODEV;
 	ctx->s_d_flags |= DCACHE_DONTCACHE;
 	ctx->ops = &pidfs_sops;
 	ctx->eops = &pidfs_export_operations;
diff --git a/mm/secretmem.c b/mm/secretmem.c
index 5f57ac4720d3..4877c262cb1f 100644
--- a/mm/secretmem.c
+++ b/mm/secretmem.c
@@ -245,8 +245,6 @@ static int secretmem_init_fs_context(struct fs_context *fc)
 	if (!ctx)
 		return -ENOMEM;
 
-	fc->s_iflags |= SB_I_NOEXEC;
-	fc->s_iflags |= SB_I_NODEV;
 	return 0;
 }
 
diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
index 69c9d6d546b2..80f201035d77 100644
--- a/virt/kvm/guest_memfd.c
+++ b/virt/kvm/guest_memfd.c
@@ -973,8 +973,6 @@ static int kvm_gmem_init_fs_context(struct fs_context *fc)
 	if (!init_pseudo(fc, GUEST_MEMFD_MAGIC))
 		return -ENOMEM;
 
-	fc->s_iflags |= SB_I_NOEXEC;
-	fc->s_iflags |= SB_I_NODEV;
 	ctx = fc->fs_private;
 	ctx->ops = &kvm_gmem_super_operations;