Messages in this thread | | | Date | Wed, 8 Apr 2020 10:20:39 -0400 | From | Peter Xu <> | Subject | Re: [PATCH 1/2] mm/mempolicy: Allow lookup_node() to handle fatal signal |
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On Wed, Apr 08, 2020 at 12:21:28PM +0200, Michal Hocko wrote: > On Tue 07-04-20 21:40:09, Peter Xu wrote: > > lookup_node() uses gup to pin the page and get node information. It > > checks against ret>=0 assuming the page will be filled in. However > > it's also possible that gup will return zero, for example, when the > > thread is quickly killed with a fatal signal. Teach lookup_node() to > > gracefully return an error -EFAULT if it happens. > > > > Meanwhile, initialize "page" to NULL to avoid potential risk of > > exploiting the pointer. > > > > Reported-by: syzbot+693dc11fcb53120b5559@syzkaller.appspotmail.com > > Fixes: 4426e945df58 ("mm/gup: allow VM_FAULT_RETRY for multiple times") > > I am not familiar with thic commit but shouldn't gup return ERESTARTSYS > on a fatal signal?
Hi, Michal,
I do see quite a few usages on -ERESTARTSYS, but also some others, majorly -EINTR, or even -EFAULT. I think it could be a more general question rather than a specific question to this patch only.
I saw some other discussions about this return value issue, I'll CC you in the other thread when I raise this as a general question.
Thanks,
-- Peter Xu
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