On Mon, 2022-02-14 at 15:24 -0800, Andrew Morton wrote: > > > Subject: [PATCH v2] mm: clean up hwpoison page cache page in fault > > path > > At first scan I thought this was a code cleanup. > > I think I'll do s/clean up/invalidate/. > OK, that sounds good. > On Sat, 12 Feb 2022 21:37:40 -0500 Rik van Riel <riel@xxxxxxxxxxx> > wrote: > > > Sometimes the page offlining code can leave behind a hwpoisoned > > clean > > page cache page. > > Is this correct behaviour? It is not desirable, and the soft page offlining code tries to invalidate the page, but I don't think overhauling the way we lock and refcount page cache pages just to make offlining them more reliable would be worthwhile, when we already have a branch in the page fault handler to deal with these pages, anyway. > > This can lead to programs being killed over and over > > and over again as they fault in the hwpoisoned page, get killed, > > and > > then get re-spawned by whatever wanted to run them. > > > > This is particularly embarrassing when the page was offlined due to > > having too many corrected memory errors. Now we are killing tasks > > due to them trying to access memory that probably isn't even > > corrupted. > > > > This problem can be avoided by invalidating the page from the page > > fault handler, which already has a branch for dealing with these > > kinds of pages. With this patch we simply pretend the page fault > > was successful if the page was invalidated, return to userspace, > > incur another page fault, read in the file from disk (to a new > > memory page), and then everything works again. > > Is this worth a cc:stable? Maybe. I don't know how far back this issue goes... -- All Rights Reversed.
Attachment:
signature.asc
Description: This is a digitally signed message part
