[PATCH -V3 0/8] migrate_pages(): fix several bugs in error path

[Huang Ying]

From: "Huang, Ying" <ying.huang@xxxxxxxxx>

During review the code of migrate_pages() and build a test program for
it.  Several bugs in error path are identified and fixed in this
series.

Most patches are tested via

- Apply error-inject.patch in Linux kernel
- Compile test-migrate.c (with -lnuma)
- Test with test-migrate.sh

error-inject.patch, test-migrate.c, and test-migrate.sh are as below.
It turns out that error injection is an important tool to fix bugs in
error path.

Changes:

v3:

- Rebased on mm-unstable (20220816)

- Added Baolin's patch to avoid retry 10 times for fail to migrate THP subpages

v2:

- Rebased on v5.19-rc5

- Addressed some comments from Baolin, Thanks!

- Added reviewed-by tags

Best Regards,
Huang, Ying

------------------------- error-inject.patch -------------------------