In the Linux kernel, the following vulnerability has been resolved: hugetlb, userfaultfd: fix reservation restore on userfaultfd error Currently in the is_continue case in hugetlb_mcopy_atomic_pte(), if we bail out using “goto out_release_unlock;” in the cases where idx >= size, or !huge_pte_none(), the code will detect that new_pagecache_page == false, and so call restore_reserve_on_error(). In this case I see restore_reserve_on_error() delete the reservation, and the following call to remove_inode_hugepages() will increment h->resv_hugepages causing a 100% reproducible leak. We should treat the is_continue case similar to adding a page into the pagecache and set new_pagecache_page to true, to indicate that there is no reservation to restore on the error path, and we need not call restore_reserve_on_error(). Rename new_pagecache_page to page_in_pagecache to make that clear.
OS | Version | Architecture | Package | Version | Filename |
---|---|---|---|---|---|
Debian | 12 | all | linux | < 5.15.5-1 | linux_5.15.5-1_all.deb |
Debian | 11 | all | linux | < 5.10.223-1 | linux_5.10.223-1_all.deb |
Debian | 999 | all | linux | < 5.15.5-1 | linux_5.15.5-1_all.deb |
Debian | 13 | all | linux | < 5.15.5-1 | linux_5.15.5-1_all.deb |