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Commit 3149c79f authored by Rik van Riel's avatar Rik van Riel Committed by Linus Torvalds
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mm,hwpoison: unmap poisoned page before invalidation

In some cases it appears the invalidation of a hwpoisoned page fails
because the page is still mapped in another process.  This can cause a
program to be continuously restarted and die when it page faults on the
page that was not invalidated.  Avoid that problem by unmapping the
hwpoisoned page when we find it.

Another issue is that sometimes we end up oopsing in finish_fault, if
the code tries to do something with the now-NULL vmf->page.  I did not
hit this error when submitting the previous patch because there are
several opportunities for alloc_set_pte to bail out before accessing
vmf->page, and that apparently happened on those systems, and most of
the time on other systems, too.

However, across several million systems that error does occur a handful
of times a day.  It can be avoided by returning VM_FAULT_NOPAGE which
will cause do_read_fault to return before calling finish_fault.

Link: https://lkml.kernel.org/r/20220325161428.5068d97e@imladris.surriel.com


Fixes: e53ac737 ("mm: invalidate hwpoison page cache page in fault path")
Signed-off-by: default avatarRik van Riel <riel@surriel.com>
Reviewed-by: default avatarMiaohe Lin <linmiaohe@huawei.com>
Tested-by: default avatarNaoya Horiguchi <naoya.horiguchi@nec.com>
Reviewed-by: default avatarOscar Salvador <osalvador@suse.de>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 4f1f9698
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