Messages in this thread | | | Date | Fri, 4 May 2018 16:54:35 +0200 | From | Oleg Nesterov <> | Subject | Re: [PATCH] memcg: Replace mm->owner with mm->memcg |
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On 05/04, Eric W. Biederman wrote: > > Oleg Nesterov <oleg@redhat.com> writes: > > > OK, what about exec() ? mm_init_memcg() initializes bprm->mm->memcg early in > > bprm_mm_init(). What if the execing task migrates before exec_mmap() ? > > We need the the cgroup when the mm is initialized. That way we have the > cgroup information when initializing the mm.
Yes, we need to initialize new_mm->memcg but iiuc mostly for the error path,
> I don't know if a lock preventing changing the cgroup in exec or just > a little bit of code in exec_mmap to ensure mm->memcg is properly set > is the better approach.
I'd vote for the change in exec_mmap(). This way mm_init_memcg() can just nullify mm->memcg.
> This does look like a very good place for an incremental patch to close > that race.
Hmm. I think v2 makes more sense, but I won't argue.
Oleg.
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