bdwgc / bdwgc / 2218

80%

Build Type

push

travis-ci

Committed by ivmai

Commit Message

Handle userfaultfd protection ranges crossing VMAs
(fix of commit e8e5a4eb1)

Issue #430 (bdwgc).

Older Linux kernels (e.g. linux 6.1) reject write-protection operations
spanning multiple VMAs, even when the entire range is registered.

Retry `ENOENT` failures as smaller page-aligned ranges, and keep
aborting if an individual page is not registered.

* os_dep.c [UFFDWP_VDB] (uffdwp_write_protect): Add assertion that
`GC_page_size` is set; define `mid_len` local variable; if `errno` is
`ENOENT`, then divide the region into 2 subregions and retry each one
(using recursion); add comments.

Coverage Stats

2 of 7 new or added lines in 1 file covered. (28.57%)

7 existing lines in 4 files now uncovered.

7175 of 8988 relevant lines covered (79.83%)

15336698.41 hits per line