Peter Xu f60b6634cd mm/selftests: add a test to verify mmap_changing race with -EAGAIN
Add an unit test to verify the recent mmap_changing ABI breakage.

Note that I used some tricks here and there to make the test simple, e.g. 
I abused UFFDIO_MOVE on top of shmem with the fact that I know what I want
to test will be even earlier than the vma type check.  Rich comments were
added to explain trivial details.

Before that fix, -EAGAIN would have been written to the copy field most of
the time but not always; the test should be able to reliably trigger the
outlier case.  After the fix, it's written always, the test verifies that
making sure corresponding field (e.g.  copy.copy for UFFDIO_COPY) is
updated.

[akpm@linux-foundation.org: coding-style cleanups]
Link: https://lkml.kernel.org/r/20250424215729.194656-3-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-05-12 23:50:45 -07:00
2025-05-12 23:50:41 -07:00
2024-09-01 20:43:24 -07:00
2022-09-28 09:02:20 +02:00
2025-02-19 14:53:27 -07:00
2025-05-11 14:54:11 -07:00
2024-03-18 03:36:32 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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