If a forking process has a thread calling (un)mmap (silly but still), the child process may have some of its mm's vm stats (total_vm and friends) screwed up, because currently they are copied from oldmm w/o holding any locks (see dup_mm). This patch moves the stats initialization to dup_mmap to be called under oldmm->mmap_sem, which eliminates any possibility of race. Also, mm->pinned_vm is not reset on fork. Let's fix it. Signed-off-by: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx> --- kernel/fork.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/kernel/fork.c b/kernel/fork.c index d2799d1fc952..eaacc75da4f7 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -365,7 +365,12 @@ static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) */ down_write_nested(&mm->mmap_sem, SINGLE_DEPTH_NESTING); + mm->total_vm = oldmm->total_vm; mm->locked_vm = 0; + mm->pinned_vm = 0; + mm->shared_vm = oldmm->shared_vm; + mm->exec_vm = oldmm->exec_vm; + mm->stack_vm = oldmm->stack_vm; mm->mmap = NULL; mm->vmacache_seqnum = 0; mm->map_count = 0; -- 1.7.10.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>