The dma-buf pseudo filesystem dispenses S_ANON_INODE inodes via
alloc_anon_inode() but never sets SB_I_NOEXEC on its superblock.
Since commit 1e7ab6f67824 ("anon_inode: rework assertions") in 6.17,
path_noexec() warns on exactly that combination, so an mmap() on any
dma-buf fd trips the warning:
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
dma-bufs have no business being executable, which is the invariant
that the new assertion is enforcing. Set SB_I_NOEXEC on the dmabuf
superblock.
Reproducer on a CONFIG_DEBUG_VFS=y kernel:
make -C tools/testing/selftests/dmabuf-heaps
sudo ./tools/testing/selftests/dmabuf-heaps/dmabuf-heap -t system
The selftest allocates from /dev/dma_heap/system and mmaps the
returned fd, which trips the warning without this patch.
Fixes: 1e7ab6f67824 ("anon_inode: rework assertions")
Cc: [email protected]
Signed-off-by: John Hubbard <[email protected]>
---
drivers/dma-buf/dma-buf.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index 71f37544a5c6..d86a99d7b8dc 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -216,6 +216,7 @@ 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;
return 0;
}
--
2.54.0
