The patch titled
Subject: mm: move memory_failure_queue() into copy_mc_[user]_highpage()
has been added to the -mm mm-unstable branch. Its filename is
mm-move-memory_failure_queue-into-copy_mc__highpage.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-move-memory_failure_queue-into-copy_mc__highpage.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
Subject: mm: move memory_failure_queue() into copy_mc_[user]_highpage()
Date: Wed, 26 Jun 2024 16:53:23 +0800
Patch series "mm: migrate: support poison recover from migrate folio", v5.
The folio migration is widely used in kernel, memory compaction, memory
hotplug, soft offline page, numa balance, memory demote/promotion, etc,
but once access a poisoned source folio when migrating, the kernel will
panic.
There is a mechanism in the kernel to recover from uncorrectable memory
errors, ARCH_HAS_COPY_MC(eg, Machine Check Safe Memory Copy on x86), which
is already used in NVDIMM or core-mm paths(eg, CoW, khugepaged, coredump,
ksm copy), see copy_mc_to_{user,kernel}, copy_mc_{user_}highpage callers.
This series of patches provide the recovery mechanism from folio copy for
the widely used folio migration. Please note, because folio migration is
no guarantee of success, so we could chose to make folio migration
tolerant of memory failures, adding folio_mc_copy() which is a #MC
versions of folio_copy(), once accessing a poisoned source folio, we could
return error and make the folio migration fail, and this could avoid the
similar panic shown below.
CPU: 1 PID: 88343 Comm: test_softofflin Kdump: loaded Not tainted 6.6.0
pc : copy_page+0x10/0xc0
lr : copy_highpage+0x38/0x50
...
Call trace:
copy_page+0x10/0xc0
folio_copy+0x78/0x90
migrate_folio_extra+0x54/0xa0
move_to_new_folio+0xd8/0x1f0
migrate_folio_move+0xb8/0x300
migrate_pages_batch+0x528/0x788
migrate_pages_sync+0x8c/0x258
migrate_pages+0x440/0x528
soft_offline_in_use_page+0x2ec/0x3c0
soft_offline_page+0x238/0x310
soft_offline_page_store+0x6c/0xc0
dev_attr_store+0x20/0x40
sysfs_kf_write+0x4c/0x68
kernfs_fop_write_iter+0x130/0x1c8
new_sync_write+0xa4/0x138
vfs_write+0x238/0x2d8
ksys_write+0x74/0x110
This patch (of 5):
There is a memory_failure_queue() call after copy_mc_[user]_highpage(),
see callers, eg, CoW/KSM page copy, it is used to mark the source page as
h/w poisoned and unmap it from other tasks, and the upcomming poison
recover from migrate folio will do the similar thing, so let's move the
memory_failure_queue() into the copy_mc_[user]_highpage() instead of
adding it into each user, this should also enhance the handling of
poisoned page in khugepaged.
Link: https://lkml.kernel.org/r/20240626085328.608006-1-wangkefeng.wang@xxxxxxxxxx
Link: https://lkml.kernel.org/r/20240626085328.608006-2-wangkefeng.wang@xxxxxxxxxx
Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
Reviewed-by: Jane Chu <jane.chu@xxxxxxxxxx>
Reviewed-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Cc: Alistair Popple <apopple@xxxxxxxxxx>
Cc: Benjamin LaHaise <bcrl@xxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Jérôme Glisse <jglisse@xxxxxxxxxx>
Cc: Jiaqi Yan <jiaqiyan@xxxxxxxxxx>
Cc: Lance Yang <ioworker0@xxxxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Muchun Song <muchun.song@xxxxxxxxx>
Cc: Naoya Horiguchi <nao.horiguchi@xxxxxxxxx>
Cc: Oscar Salvador <osalvador@xxxxxxx>
Cc: Tony Luck <tony.luck@xxxxxxxxx>
Cc: Vishal Moola (Oracle) <vishal.moola@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/highmem.h | 6 ++++++
mm/ksm.c | 1 -
mm/memory.c | 12 +++---------
3 files changed, 9 insertions(+), 10 deletions(-)
--- a/include/linux/highmem.h~mm-move-memory_failure_queue-into-copy_mc__highpage
+++ a/include/linux/highmem.h
@@ -352,6 +352,9 @@ static inline int copy_mc_user_highpage(
kunmap_local(vto);
kunmap_local(vfrom);
+ if (ret)
+ memory_failure_queue(page_to_pfn(from), 0);
+
return ret;
}
@@ -368,6 +371,9 @@ static inline int copy_mc_highpage(struc
kunmap_local(vto);
kunmap_local(vfrom);
+ if (ret)
+ memory_failure_queue(page_to_pfn(from), 0);
+
return ret;
}
#else
--- a/mm/ksm.c~mm-move-memory_failure_queue-into-copy_mc__highpage
+++ a/mm/ksm.c
@@ -2998,7 +2998,6 @@ struct folio *ksm_might_need_to_copy(str
if (copy_mc_user_highpage(folio_page(new_folio, 0), page,
addr, vma)) {
folio_put(new_folio);
- memory_failure_queue(folio_pfn(folio), 0);
return ERR_PTR(-EHWPOISON);
}
folio_set_dirty(new_folio);
--- a/mm/memory.c~mm-move-memory_failure_queue-into-copy_mc__highpage
+++ a/mm/memory.c
@@ -3022,10 +3022,8 @@ static inline int __wp_page_copy_user(st
unsigned long addr = vmf->address;
if (likely(src)) {
- if (copy_mc_user_highpage(dst, src, addr, vma)) {
- memory_failure_queue(page_to_pfn(src), 0);
+ if (copy_mc_user_highpage(dst, src, addr, vma))
return -EHWPOISON;
- }
return 0;
}
@@ -6492,10 +6490,8 @@ static int copy_user_gigantic_page(struc
cond_resched();
if (copy_mc_user_highpage(dst_page, src_page,
- addr + i*PAGE_SIZE, vma)) {
- memory_failure_queue(page_to_pfn(src_page), 0);
+ addr + i*PAGE_SIZE, vma))
return -EHWPOISON;
- }
}
return 0;
}
@@ -6512,10 +6508,8 @@ static int copy_subpage(unsigned long ad
struct page *dst = folio_page(copy_arg->dst, idx);
struct page *src = folio_page(copy_arg->src, idx);
- if (copy_mc_user_highpage(dst, src, addr, copy_arg->vma)) {
- memory_failure_queue(page_to_pfn(src), 0);
+ if (copy_mc_user_highpage(dst, src, addr, copy_arg->vma))
return -EHWPOISON;
- }
return 0;
}
_
Patches currently in -mm which might be from wangkefeng.wang@xxxxxxxxxx are
fs-proc-task_mmu-use-folio-api-in-pte_is_pinned.patch
mm-remove-page_maybe_dma_pinned.patch
mm-remove-page_maybe_dma_pinned-fix.patch
fb_defio-use-a-folio-in-fb_deferred_io_work.patch
mm-remove-page_mkclean.patch
mm-memory-convert-clear_huge_page-to-folio_zero_user.patch
mm-memory-use-folio-in-struct-copy_subpage_arg.patch
mm-memory-improve-copy_user_large_folio.patch
mm-memory-rename-pages_per_huge_page-to-nr_pages.patch
mm-move-memory_failure_queue-into-copy_mc__highpage.patch
mm-add-folio_mc_copy.patch
mm-migrate-split-folio_migrate_mapping.patch
mm-migrate-support-poisoned-recover-from-migrate-folio.patch
fs-hugetlbfs-support-poisoned-recover-from-hugetlbfs_migrate_folio.patch
mm-migrate-remove-folio_migrate_copy.patch
