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KSM hints will require locking mmap_sem for write since they modify vm_flags, so for remote KSM hinting this additional check is needed. Reviewed-by: Suren Baghdasaryan Signed-off-by: Oleksandr Natalenko Signed-off-by: Minchan Kim --- mm/madvise.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/madvise.c b/mm/madvise.c index e794367f681e..e77c6c1fad34 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -1118,6 +1118,8 @@ int do_madvise(struct task_struct *target_task, str= uct mm_struct *mm, if (write) { if (down_write_killable(&mm->mmap_sem)) return -EINTR; + if (current->mm !=3D mm && !mmget_still_valid(mm)) + goto skip_mm; } else { down_read(&mm->mmap_sem); } @@ -1169,6 +1171,7 @@ int do_madvise(struct task_struct *target_task, str= uct mm_struct *mm, } out: blk_finish_plug(&plug); +skip_mm: if (write) up_write(&mm->mmap_sem); else --=20 2.25.0.265.gbab2e86ba0-goog