In the Linux kernel, the following vulnerability has been resolved: iommufd: Fix out_fput in iommufd_fault_alloc() As fput() calls the file->f_op->release op, where fault obj and ictx are getting released, there is no need to release these two after fput() one more time, which would result in imbalanced refcounts: refcount_t: decrement hit 0; leaking memory. WARNING: CPU: 48 PID: 2369 at lib/refcount.c:31 refcount_warn_saturate+0x60/0x230 Call trace: refcount_warn_saturate+0x60/0x230 (P) refcount_warn_saturate+0x60/0x230 (L) iommufd_fault_fops_release+0x9c/0xe0 [iommufd] ... VFS: Close: file count is 0 (f_op=iommufd_fops [iommufd]) WARNING: CPU: 48 PID: 2369 at fs/open.c:1507 filp_flush+0x3c/0xf0 Call trace: filp_flush+0x3c/0xf0 (P) filp_flush+0x3c/0xf0 (L) __arm64_sys_close+0x34/0x98 ... imbalanced put on file reference count WARNING: CPU: 48 PID: 2369 at fs/file.c:74 __file_ref_put+0x100/0x138 Call trace: __file_ref_put+0x100/0x138 (P) __file_ref_put+0x100/0x138 (L) __fput_sync+0x4c/0xd0 Drop those two lines to fix the warnings above.