fuse: fix invalidate lock leak on setattr writeback failure

Summary

In the Linux kernel, the following vulnerability has been resolved: fuse: fix invalidate lock leak on setattr writeback failure fuse_do_setattr() takes filemap_invalidate_lock() for a DAX truncate (fault_blocked = true) and releases it at the out:/error: labels. But when a writeback flush is also needed, a write_inode_now() failure returns directly and leaks the lock, so any later fault or truncate on the file stalls on the stale rwsem. For example, truncate(2) on a setuid file reaches fuse_do_setattr() with both ATTR_SIZE and ATTR_MODE set: truncate(2) └─ do_truncate() ├─ dentry_needs_remove_privs() # S_ISUID └─ notify_change() # KILL_SUID -> ATTR_MODE └─ fuse_setattr() # no killpriv: │ # ia_valid |= ATTR_MODE └─ fuse_do_setattr() ├─ filemap_invalidate_lock() # IS_DAX && is_truncate └─ write_inode_now() # is_wb && ATTR_MODE └─ if (err) # e.g. daemon -> -EIO return err # <- lock leaked Fix this by adding an unlock label that releases the lock before returning the error, and use it for the fuse_dax_break_layouts() failure path as well.

Timeline

1. Sep 4, 2026, 3:55 PM UTCCVE published
2. Oct 30, 2026, 12:31 PM UTCRecord last updated

Affected versions

• Linux Linux

  Version range not reported

• Linux Linux

  5.10

• KernelLinux

  From 5.10.0 · fixed in 5.15.220; From 5.16.0 · fixed in 6.1.187; From 6.2.0 · fixed in 6.6.156; From 6.7.0 · fixed in 6.12.108; From 6.13.0 · fixed in 6.18.49; From 6.19.0 · fixed in 7.1.13; From 7.2.0 · fixed in 7.2.3

References 9