From 48d212a2eecaca2e1875925837ad27b2f43f48a3 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Thu, 7 Jun 2012 17:54:07 -0700 Subject: Revert "mm: correctly synchronize rss-counters at exit/exec" This reverts commit 40af1bbdca47e5c8a2044039bb78ca8fd8b20f94. It's horribly and utterly broken for at least the following reasons: - calling sync_mm_rss() from mmput() is fundamentally wrong, because there's absolutely no reason to believe that the task that does the mmput() always does it on its own VM. Example: fork, ptrace, /proc - you name it. - calling it *after* having done mmdrop() on it is doubly insane, since the mm struct may well be gone now. - testing mm against NULL before you call it is insane too, since a NULL mm there would have caused oopses long before. .. and those are just the three bugs I found before I decided to give up looking for me and revert it asap. I should have caught it before I even took it, but I trusted Andrew too much. Cc: Konstantin Khlebnikov Cc: Markus Trippelsdorf Cc: Hugh Dickins Cc: KAMEZAWA Hiroyuki Cc: Oleg Nesterov Cc: Andrew Morton Signed-off-by: Linus Torvalds --- fs/exec.c | 1 + 1 file changed, 1 insertion(+) (limited to 'fs/exec.c') diff --git a/fs/exec.c b/fs/exec.c index b926ed19301e..a79786a8d2c8 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -819,6 +819,7 @@ static int exec_mmap(struct mm_struct *mm) /* Notify parent that we're no longer interested in the old VM */ tsk = current; old_mm = current->mm; + sync_mm_rss(old_mm); mm_release(tsk, old_mm); if (old_mm) { -- cgit v1.2.3