From: Peter Xu <pet...@redhat.com> Now we recycle the uffd servicing threads earlier than the lock threads. It might happen that when the lock thread is still blocked at a pthread mutex lock while the servicing thread has already quitted for the cpu so the lock thread will be blocked forever and hang the test program. To fix the possible race, recycle the lock threads first.
This never happens with current missing-only tests, but when I start to run the write-protection tests (the feature is not yet posted upstream) it happens every time of the run possibly because in that new test we'll need to service two page faults for each lock operation. Link: http://lkml.kernel.org/r/20180930074259.18229-4-pet...@redhat.com Signed-off-by: Peter Xu <pet...@redhat.com> Acked-by: Mike Rapoport <r...@linux.vnet.ibm.com> Cc: Shuah Khan <sh...@kernel.org> Cc: Mike Kravetz <mike.krav...@oracle.com> Cc: Jerome Glisse <jgli...@redhat.com> Cc: Zi Yan <zi....@cs.rutgers.edu> Cc: "Kirill A . Shutemov" <kir...@shutemov.name> Cc: Shaohua Li <s...@fb.com> Cc: Andrea Arcangeli <aarca...@redhat.com> Cc: "Dr . David Alan Gilbert" <dgilb...@redhat.com> Signed-off-by: Andrew Morton <a...@linux-foundation.org> Signed-off-by: Linus Torvalds <torva...@linux-foundation.org> https://jira.sw.ru/browse/PSBM-102938 (cherry picked from commit 7eaa8c969efa77127de9a05856eef9e5d22cf487) Signed-off-by: Andrey Ryabinin <aryabi...@virtuozzo.com> --- tools/testing/selftests/vm/userfaultfd.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/tools/testing/selftests/vm/userfaultfd.c b/tools/testing/selftests/vm/userfaultfd.c index 7b8171e3128a..68bbe0eb203e 100644 --- a/tools/testing/selftests/vm/userfaultfd.c +++ b/tools/testing/selftests/vm/userfaultfd.c @@ -605,6 +605,12 @@ static int stress(unsigned long *userfaults) if (uffd_test_ops->release_pages(area_src)) return 1; + + finished = 1; + for (cpu = 0; cpu < nr_cpus; cpu++) + if (pthread_join(locking_threads[cpu], NULL)) + return 1; + for (cpu = 0; cpu < nr_cpus; cpu++) { char c; if (bounces & BOUNCE_POLL) { @@ -622,11 +628,6 @@ static int stress(unsigned long *userfaults) } } - finished = 1; - for (cpu = 0; cpu < nr_cpus; cpu++) - if (pthread_join(locking_threads[cpu], NULL)) - return 1; - return 0; } -- 2.25.3 _______________________________________________ Devel mailing list Devel@openvz.org https://lists.openvz.org/mailman/listinfo/devel
