debugfs: Fix the missing initializations in __debugfs_file_get()

both method table pointers in debugfs_fsdata need to be initialized,
obviously, and calculating the bitmap of present methods would also
go better if we start with initialized state.

Fixes: 41a0ecc0997c ("debugfs: get rid of dynamically allocation proxy_ops")
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Link: https://lore.kernel.org/r/20250129191937.GR1977892@ZenIV
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c
index e33cc77699cd56111ca19b9a91c1be92fb99affe..69e9ddcb113dfe370cc96d3d80689cd587db6eca 100644 (file)
--- a/fs/debugfs/file.c
+++ b/fs/debugfs/file.c
@@ -94,6 +94,7 @@ static int __debugfs_file_get(struct dentry *dentry, enum dbgfs_get_mode mode)
                fsd = d_fsd;
        } else {
                struct inode *inode = dentry->d_inode;
+               unsigned int methods = 0;
 
                if (WARN_ON(mode == DBGFS_GET_ALREADY))
                        return -EINVAL;
@@ -106,25 +107,28 @@ static int __debugfs_file_get(struct dentry *dentry, enum dbgfs_get_mode mode)
                        const struct debugfs_short_fops *ops;
                        ops = fsd->short_fops = DEBUGFS_I(inode)->short_fops;
                        if (ops->llseek)
-                               fsd->methods |= HAS_LSEEK;
+                               methods |= HAS_LSEEK;
                        if (ops->read)
-                               fsd->methods |= HAS_READ;
+                               methods |= HAS_READ;
                        if (ops->write)
-                               fsd->methods |= HAS_WRITE;
+                               methods |= HAS_WRITE;
+                       fsd->real_fops = NULL;
                } else {
                        const struct file_operations *ops;
                        ops = fsd->real_fops = DEBUGFS_I(inode)->real_fops;
                        if (ops->llseek)
-                               fsd->methods |= HAS_LSEEK;
+                               methods |= HAS_LSEEK;
                        if (ops->read)
-                               fsd->methods |= HAS_READ;
+                               methods |= HAS_READ;
                        if (ops->write)
-                               fsd->methods |= HAS_WRITE;
+                               methods |= HAS_WRITE;
                        if (ops->unlocked_ioctl)
-                               fsd->methods |= HAS_IOCTL;
+                               methods |= HAS_IOCTL;
                        if (ops->poll)
-                               fsd->methods |= HAS_POLL;
+                               methods |= HAS_POLL;
+                       fsd->short_fops = NULL;
                }
+               fsd->methods = methods;
                refcount_set(&fsd->active_users, 1);
                init_completion(&fsd->active_users_drained);
                INIT_LIST_HEAD(&fsd->cancellations);