The patch titled
Subject: mm/hmm: Fix bad subpage pointer in try_to_unmap_one
has been added to the -mm tree. Its filename is
mm-hmm-fix-bad-subpage-pointer-in-try_to_unmap_one.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-hmm-fix-bad-subpage-pointer-in-try_to_unmap_one.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-hmm-fix-bad-subpage-pointer-in-try_to_unmap_one.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Ralph Campbell <rcampbell@xxxxxxxxxx>
Subject: mm/hmm: Fix bad subpage pointer in try_to_unmap_one
When migrating a ZONE device private page from device memory to system
memory, the subpage pointer is initialized from a swap pte which computes
an invalid page pointer. A kernel panic results such as:
BUG: unable to handle page fault for address: ffffea1fffffffc8
Initialize subpage correctly before calling page_remove_rmap().
Link: http://lkml.kernel.org/r/20190709223556.28908-1-rcampbell@xxxxxxxxxx
Fixes: a5430dda8a3a1c ("mm/migrate: support un-addressable ZONE_DEVICE page in migration")
Signed-off-by: Ralph Campbell <rcampbell@xxxxxxxxxx>
Cc: "Jérôme Glisse" <jglisse@xxxxxxxxxx>
Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/rmap.c | 1 +
1 file changed, 1 insertion(+)
--- a/mm/rmap.c~mm-hmm-fix-bad-subpage-pointer-in-try_to_unmap_one
+++ a/mm/rmap.c
@@ -1476,6 +1476,7 @@ static bool try_to_unmap_one(struct page
* No need to invalidate here it will synchronize on
* against the special swap migration pte.
*/
+ subpage = page;
goto discard;
}
_
Patches currently in -mm which might be from rcampbell@xxxxxxxxxx are
mm-hmm-fix-bad-subpage-pointer-in-try_to_unmap_one.patch
