The patch titled
Subject: mm: do_swap_page(): fix up the error code
has been added to the -mm tree. Its filename is
mm-do_swap_page-fix-up-the-error-code-instantiation.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-do_swap_page-fix-up-the-error-code-instantiation.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-do_swap_page-fix-up-the-error-code-instantiation.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: Michal Hocko <mhocko@xxxxxxxx>
Subject: mm: do_swap_page(): fix up the error code
do_swap_page() returns error codes from the VM_FAULT* space. try_charge()
might return -ENOMEM, though, and then do_swap_page() simply returns 0
which means a success.
We almost never return ENOMEM for GFP_KERNEL single page charge. Except
for async OOM handling (oom_disabled v1). So this needs translation to
VM_FAULT_OOM otherwise the the page fault path will not notify the
userspace and wait for an action.
Link: http://lkml.kernel.org/r/20200617090238.GL9499@xxxxxxxxxxxxxx
Fixes: 4c6355b25e8b ("mm: memcontrol: charge swapin pages on instantiation")
Signed-off-by: Michal Hocko <mhocko@xxxxxxxx>
Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Alex Shi <alex.shi@xxxxxxxxxxxxxxxxx>
Cc: Joonsoo Kim <js1304@xxxxxxxxx>
Cc: Shakeel Butt <shakeelb@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: "Kirill A. Shutemov" <kirill@xxxxxxxxxxxxx>
Cc: Roman Gushchin <guro@xxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/mm/memory.c~mm-do_swap_page-fix-up-the-error-code-instantiation
+++ a/mm/memory.c
@@ -3140,8 +3140,10 @@ vm_fault_t do_swap_page(struct vm_fault
err = mem_cgroup_charge(page, vma->vm_mm,
GFP_KERNEL);
ClearPageSwapCache(page);
- if (err)
+ if (err) {
+ ret = VM_FAULT_OOM;
goto out_page;
+ }
lru_cache_add(page);
swap_readpage(page, true);
_
Patches currently in -mm which might be from mhocko@xxxxxxxx are
mm-do_swap_page-fix-up-the-error-code-instantiation.patch
