diff options
| author | John Hubbard <jhubbard@nvidia.com> | 2026-06-04 05:53:14 +0300 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2026-06-04 11:10:49 +0300 |
| commit | 6de2aeffabaafaeda819e60ec8d04f199711e11a (patch) | |
| tree | 4d5dc908267b970b3b7d9a8045336db957f97986 | |
| parent | 6dd3c6884cd9defb511284b566cef5ac8f657dbf (diff) | |
| download | linux-6de2aeffabaafaeda819e60ec8d04f199711e11a.tar.xz | |
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@infradead.org>
Cc: stable@vger.kernel.org
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Link: https://patch.msgid.link/20260604025315.245910-2-jhubbard@nvidia.com
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
| -rw-r--r-- | fs/libfs.c | 1 |
1 files changed, 1 insertions, 0 deletions
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; |