Hello, Andrew. On Wed, Mar 14, 2018 at 01:56:31PM -0700, Andrew Morton wrote: > It would benefit from a comment explaining why we're doing this (it's > for the oom-killer). Will add. > My memory is weak and our documentation is awful. What does > mutex_lock_killable() actually do and how does it differ from > mutex_lock_interruptible()? Userspace tasks can run pcpu_alloc() and I IIRC, killable listens only to SIGKILL. > wonder if there's any way in which a userspace-delivered signal can > disrupt another userspace task's memory allocation attempt? Hmm... maybe. Just honoring SIGKILL *should* be fine but the alloc failure paths might be broken, so there are some risks. Given that the cases where userspace tasks end up allocation percpu memory is pretty limited and/or priviledged (like mount, bpf), I don't think the risks are high tho. Thanks. -- tejun
