[SRU][R][PATCH 1/1] UBUNTU: SAUCE: dma-buf: set SB_I_NOEXEC and SB_I_NODEV on dmabuf filesystem

[AceLan Kao]

From: "Chia-Lin Kao (AceLan)" <acelan.kao at canonical.com>

BugLink: https://bugs.launchpad.net/bugs/2139656

The VFS now warns if an inode flagged with S_ANON_INODE is located on a
filesystem that does not have SB_I_NOEXEC set. dmabuf inodes are
created using alloc_anon_inode(), which sets S_ANON_INODE.

This triggers a warning in path_noexec() when a dmabuf is mmapped, for
example by GStreamer's v4l2src element.

[   60.061328] WARNING: CPU: 2 PID: 2803 at fs/exec.c:125 path_noexec+0xa0/0xd0
...
[   60.061637]  do_mmap+0x2b5/0x680

Fix this by setting SB_I_NOEXEC and SB_I_NODEV on the dmabuf filesystem
context, following the same pattern as commit ce7419b6cf23d ("anon_inode:
raise SB_I_NODEV and SB_I_NOEXEC").

Signed-off-by: Chia-Lin Kao (AceLan) <acelan.kao at canonical.com>
(cherry picked from commit https://lore.kernel.org/lkml/20260114011917.241196-1-acelan.kao@canonical.com/)
Signed-off-by: Chia-Lin Kao (AceLan) <acelan.kao at canonical.com>
---
 drivers/dma-buf/dma-buf.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index 11711874a325b..171fc980c80bf 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -216,6 +216,8 @@ static int dma_buf_fs_init_context(struct fs_context *fc)
 	if (!ctx)
 		return -ENOMEM;
 	ctx->dops = &dma_buf_dentry_ops;
+	fc->s_iflags |= SB_I_NOEXEC;
+	fc->s_iflags |= SB_I_NODEV;
 	return 0;
 }
 
-- 
2.53.0