linux-kernel - [PATCH] dma-buf: set SB_I_NOEXEC and SB_I

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Message-ID: <20260114011917.241196-1-acelan.kao@canonical.com>
Date: Wed, 14 Jan 2026 09:19:16 +0800
From: "Chia-Lin Kao (AceLan)" <acelan.kao@...onical.com>
To: Sumit Semwal <sumit.semwal@...aro.org>,
	Christian König <christian.koenig@....com>,
	linux-media@...r.kernel.org,
	dri-devel@...ts.freedesktop.org,
	linaro-mm-sig@...ts.linaro.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] dma-buf: set SB_I_NOEXEC and SB_I_NODEV on dmabuf filesystem

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

The warning was introduced by commit 1e7ab6f67824 ("anon_inode: rework
assertions") which added enforcement that anonymous inodes must be on
filesystems with SB_I_NOEXEC set.

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") and commit 98f99394a104c ("secretmem:
use SB_I_NOEXEC").

Signed-off-by: Chia-Lin Kao (AceLan) <acelan.kao@...onical.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 a4d8f2ff94e46..dea79aaab10ce 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -221,6 +221,8 @@ 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;
 }

-- 
2.51.0