The patch titled
Subject: mm, hugetlb_cgroup: suppress SIGBUS when hugetlb_cgroup charge fails
has been added to the -mm tree. Its filename is
mm-hugetlb_cgroup-suppress-sigbus-when-hugetlb_cgroup-charge-fails.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-hugetlb_cgroup-suppress-sigbus-when-hugetlb_cgroup-charge-fails.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-hugetlb_cgroup-suppress-sigbus-when-hugetlb_cgroup-charge-fails.patch
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*** 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: David Rientjes <rientjes@xxxxxxxxxx>
Subject: mm, hugetlb_cgroup: suppress SIGBUS when hugetlb_cgroup charge fails
When charging to a hugetlb_cgroup fails, alloc_huge_page() returns
ERR_PTR(-ENOSPC) which will cause VM_FAULT_SIGBUS to be returned to the
page fault handler.
This is because the return value from hugetlb_cgroup_charge_cgroup() is
overwritten with ERR_PTR(-ENOSPC).
Instead, propagate the error code from hugetlb_cgroup_charge_cgroup()
(ERR_PTR(-ENOMEM)), so VM_FAULT_OOM is handled correctly. This is
consistent with failing mem cgroup charges in the non-hugetlb fault path.
At the same time, restructure the return paths of alloc_huge_page() so it
is consistent.
Link: http://lkml.kernel.org/r/alpine.DEB.2.21.1805251316090.167008@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/hugetlb.c | 18 ++++++++++++------
1 file changed, 12 insertions(+), 6 deletions(-)
diff -puN mm/hugetlb.c~mm-hugetlb_cgroup-suppress-sigbus-when-hugetlb_cgroup-charge-fails mm/hugetlb.c
--- a/mm/hugetlb.c~mm-hugetlb_cgroup-suppress-sigbus-when-hugetlb_cgroup-charge-fails
+++ a/mm/hugetlb.c
@@ -2006,8 +2006,10 @@ struct page *alloc_huge_page(struct vm_a
* code of zero indicates a reservation exists (no change).
*/
map_chg = gbl_chg = vma_needs_reservation(h, vma, addr);
- if (map_chg < 0)
- return ERR_PTR(-ENOMEM);
+ if (map_chg < 0) {
+ ret = -ENOMEM;
+ goto out;
+ }
/*
* Processes that did not create the mapping will have no
@@ -2019,8 +2021,8 @@ struct page *alloc_huge_page(struct vm_a
if (map_chg || avoid_reserve) {
gbl_chg = hugepage_subpool_get_pages(spool, 1);
if (gbl_chg < 0) {
- vma_end_reservation(h, vma, addr);
- return ERR_PTR(-ENOSPC);
+ ret = -ENOSPC;
+ goto out_reservation;
}
/*
@@ -2049,8 +2051,10 @@ struct page *alloc_huge_page(struct vm_a
if (!page) {
spin_unlock(&hugetlb_lock);
page = alloc_buddy_huge_page_with_mpol(h, vma, addr);
- if (!page)
+ if (!page) {
+ ret = -ENOSPC;
goto out_uncharge_cgroup;
+ }
if (!avoid_reserve && vma_has_reserves(vma, gbl_chg)) {
SetPagePrivate(page);
h->resv_huge_pages--;
@@ -2087,8 +2091,10 @@ out_uncharge_cgroup:
out_subpool_put:
if (map_chg || avoid_reserve)
hugepage_subpool_put_pages(spool, 1);
+out_reservation:
vma_end_reservation(h, vma, addr);
- return ERR_PTR(-ENOSPC);
+out:
+ return ERR_PTR(ret);
}
int alloc_bootmem_huge_page(struct hstate *h)
_
Patches currently in -mm which might be from rientjes@xxxxxxxxxx are
mm-hugetlb_cgroup-suppress-sigbus-when-hugetlb_cgroup-charge-fails.patch
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