From: Kees Cook <[email protected]> [ Upstream commit a43e0fc5e9134a46515de2f2f8d4100b74e50de3 ]
Unloading a modular pstore backend with records in pstorefs would trigger the dput() double-drop warning: WARNING: CPU: 0 PID: 2569 at fs/dcache.c:762 dput.part.0+0x3f3/0x410 Using the combo of d_drop()/dput() (as mentioned in Documentation/filesystems/vfs.rst) isn't the right approach here, and leads to the reference counting problem seen above. Use d_invalidate() and update the code to not bother checking for error codes that can never happen. Suggested-by: Alexander Viro <[email protected]> Fixes: 609e28bb139e ("pstore: Remove filesystem records when backend is unregistered") Signed-off-by: Kees Cook <[email protected]> --- Cc: "Guilherme G. Piccoli" <[email protected]> Cc: Tony Luck <[email protected]> Cc: [email protected] [ Minor context change fixed. ] Signed-off-by: Robert Garcia <[email protected]> --- fs/pstore/inode.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c index 14658b009f1b..f56e0b105be7 100644 --- a/fs/pstore/inode.c +++ b/fs/pstore/inode.c @@ -312,7 +312,6 @@ int pstore_put_backend_records(struct pstore_info *psi) { struct pstore_private *pos, *tmp; struct dentry *root; - int rc = 0; root = psinfo_lock_root(); if (!root) @@ -322,11 +321,8 @@ int pstore_put_backend_records(struct pstore_info *psi) list_for_each_entry_safe(pos, tmp, &records_list, list) { if (pos->record->psi == psi) { list_del_init(&pos->list); - rc = simple_unlink(d_inode(root), pos->dentry); - if (WARN_ON(rc)) - break; - d_drop(pos->dentry); - dput(pos->dentry); + d_invalidate(pos->dentry); + simple_unlink(d_inode(root), pos->dentry); pos->dentry = NULL; } } @@ -334,7 +330,7 @@ int pstore_put_backend_records(struct pstore_info *psi) inode_unlock(d_inode(root)); - return rc; + return 0; } /* -- 2.34.1
