4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Shuxiao Zhang <zhangshuxiao@xxxxxxxxxx>
commit 97fbfef6bd597888485b653175fb846c6998b60c upstream.
vfs_llseek will check whether the file mode has
FMODE_LSEEK, no return failure. But ashmem can be
lseek, so add FMODE_LSEEK to ashmem file.
Comment From Greg Hackmann:
ashmem_llseek() passes the llseek() call through to the backing
shmem file. 91360b02ab48 ("ashmem: use vfs_llseek()") changed
this from directly calling the file's llseek() op into a VFS
layer call. This also adds a check for the FMODE_LSEEK bit, so
without that bit ashmem_llseek() now always fails with -ESPIPE.
Fixes: 91360b02ab48 ("ashmem: use vfs_llseek()")
Signed-off-by: Shuxiao Zhang <zhangshuxiao@xxxxxxxxxx>
Tested-by: Greg Hackmann <ghackmann@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/staging/android/ashmem.c | 1 +
1 file changed, 1 insertion(+)
--- a/drivers/staging/android/ashmem.c
+++ b/drivers/staging/android/ashmem.c
@@ -405,6 +405,7 @@ static int ashmem_mmap(struct file *file
ret = PTR_ERR(vmfile);
goto out;
}
+ vmfile->f_mode |= FMODE_LSEEK;
asma->file = vmfile;
}
get_file(asma->file);