mm: invalidate hwpoison page cache page in fault path

Linux Kernel / Linux Kernel - Rik van Riel [surriel.com] - 22 March 2022 22:57 UTC

Sometimes the page offlining code can leave behind a hwpoisoned clean page cache page. 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.

Link: https://lkml.kernel.org/r/20220212213740.423efcea@imladris.surriel.com

e53ac7374e64 mm: invalidate hwpoison page cache page in fault path
mm/memory.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

Upstream: git.kernel.org


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