Messages in this thread Patch in this message | | | From | Minchan Kim <> | Subject | [PATCH 3/4] mm/madvise: employ mmget_still_valid for write lock | Date | Fri, 10 Jan 2020 13:34:32 -0800 |
| |
From: Oleksandr Natalenko <oleksandr@redhat.com>
Do the very same trick as we already do since 04f5866e41fb. KSM hints will require locking mmap_sem for write since they modify vm_flags, so for remote KSM hinting this additional check is needed.
Signed-off-by: Oleksandr Natalenko <oleksandr@redhat.com> Signed-off-by: Minchan Kim <minchan@kernel.org> --- mm/madvise.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/mm/madvise.c b/mm/madvise.c index e15dfb4df7bf..eb42b2b7f49b 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -1059,6 +1059,8 @@ static int madvise_common(struct task_struct *task, struct mm_struct *mm, if (write) { if (down_write_killable(&mm->mmap_sem)) return -EINTR; + if (current->mm != mm && !mmget_still_valid(mm)) + goto skip_mm; } else { down_read(&mm->mmap_sem); } @@ -1109,6 +1111,7 @@ static int madvise_common(struct task_struct *task, struct mm_struct *mm, } out: blk_finish_plug(&plug); +skip_mm: if (write) up_write(&mm->mmap_sem); else -- 2.25.0.rc1.283.g88dfdc4193-goog
| |