Messages in this thread Patch in this message | | | From | jglisse@redhat ... | Subject | [PATCH 04/15] mm/hmm: unregister mmu_notifier when last HMM client quit | Date | Mon, 19 Mar 2018 22:00:26 -0400 |
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From: Jérôme Glisse <jglisse@redhat.com>
This code was lost in translation at one point. This properly call mmu_notifier_unregister_no_release() once last user is gone. This fix the zombie mm_struct as without this patch we do not drop the refcount we have on it.
Signed-off-by: Jérôme Glisse <jglisse@redhat.com> Cc: Evgeny Baskakov <ebaskakov@nvidia.com> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: Mark Hairgrove <mhairgrove@nvidia.com> Cc: John Hubbard <jhubbard@nvidia.com> --- mm/hmm.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+)
diff --git a/mm/hmm.c b/mm/hmm.c index 6088fa6ed137..667944630dc9 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -244,10 +244,29 @@ EXPORT_SYMBOL(hmm_mirror_register); void hmm_mirror_unregister(struct hmm_mirror *mirror) { struct hmm *hmm = mirror->hmm; + struct mm_struct *mm = NULL; + bool unregister = false; down_write(&hmm->mirrors_sem); list_del_init(&mirror->list); + unregister = list_empty(&hmm->mirrors); up_write(&hmm->mirrors_sem); + + if (!unregister) + return; + + spin_lock(&hmm->mm->page_table_lock); + if (hmm->mm->hmm == hmm) { + mm = hmm->mm; + mm->hmm = NULL; + } + spin_unlock(&hmm->mm->page_table_lock); + + if (mm == NULL) + return; + + mmu_notifier_unregister_no_release(&hmm->mmu_notifier, mm); + kfree(hmm); } EXPORT_SYMBOL(hmm_mirror_unregister); -- 2.14.3
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