CVE-2026-68312cifs: fix cifsFileInfo leak on kmalloc failure in deferred close drain paths

Official description

In the Linux kernel, the following vulnerability has been resolved: cifs: fix cifsFileInfo leak on kmalloc failure in deferred close drain paths In cifs_close_deferred_file(), cifs_close_all_deferred_files(), and cifs_close_deferred_file_under_dentry(), when a pending deferred close is cancelled via cancel_delayed_work(), the subsequent kmalloc_obj() to add the file to the local processing list may fail under memory pressure. The loop breaks immediately, but the cancelled work is no longer pending (it would have called _cifsFileInfo_put()), and the cfile is never added to file_head for processing. The cifsFileInfo reference and the open server handle both leak. Fix by saving the cfile that failed allocation in a local variable, breaking as before, and calling _cifsFileInfo_put() on it after releasing the lock. Any files later in the iteration are unaffected since their deferred work is still pending and will fire normally.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/75143abc21f627da7ee3b0336814bd702692e830
• https://git.kernel.org/stable/c/c968b2417f6a15d35ff4b97d534af4a126cb510b
• https://git.kernel.org/stable/c/7af7ec3af091f55d01f0ebe0246d10e37f358311
• https://git.kernel.org/stable/c/6089f561e2c31a3ba52836c75c7d2ab50d2eea41
• https://git.kernel.org/stable/c/32390b3f06f26e366cfb27dbac4bc0196c321535
• https://git.kernel.org/stable/c/c2f2e83e3bbc5483730fd4ee903182761f1ae50f