The patch titled
Subject: mm: fix panic caused by __page_handle_poison()
has been added to the -mm tree. Its filename is
mm-fix-panic-caused-by-__page_handle_poison.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-fix-panic-caused-by-__page_handle_poison.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-fix-panic-caused-by-__page_handle_poison.patch
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------------------------------------------------------
From: Michael Wang <yun.wang@xxxxxxxxxxxxxxxxx>
Subject: mm: fix panic caused by __page_handle_poison()
In commit 510d25c92ec4 ("mm/hwpoison: disable pcp for
page_handle_poison()"), __page_handle_poison() was introduced, and if we
mark:
RET_A = dissolve_free_huge_page();
RET_B = take_page_off_buddy();
then __page_handle_poison was supposed to return TRUE When RET_A == 0 &&
RET_B == TRUE
But since it failed to take care the case when RET_A is -EBUSY or -ENOMEM,
and just return the ret as a bool which actually become TRUE, it break the
original logic.
The following result is a huge page in freelist but was
referenced as poisoned, and lead into the final panic:
kernel BUG at mm/internal.h:95!
invalid opcode: 0000 [#1] SMP PTI
skip...
RIP: 0010:set_page_refcounted mm/internal.h:95 [inline]
RIP: 0010:remove_hugetlb_page+0x23c/0x240 mm/hugetlb.c:1371
skip...
Call Trace:
remove_pool_huge_page+0xe4/0x110 mm/hugetlb.c:1892
return_unused_surplus_pages+0x8d/0x150 mm/hugetlb.c:2272
hugetlb_acct_memory.part.91+0x524/0x690 mm/hugetlb.c:4017
This patch replaces 'bool' with 'int' to handle RET_A correctly.
Link: https://lkml.kernel.org/r/61782ac6-1e8a-4f6f-35e6-e94fce3b37f5@xxxxxxxxxxxxxxxxx
Fixes: 510d25c92ec4 ("mm/hwpoison: disable pcp for page_handle_poison()")
Signed-off-by: Michael Wang <yun.wang@xxxxxxxxxxxxxxxxx>
Acked-by: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
Reported-by: Abaci <abaci@xxxxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> [5.14+]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory-failure.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/mm/memory-failure.c~mm-fix-panic-caused-by-__page_handle_poison
+++ a/mm/memory-failure.c
@@ -68,7 +68,7 @@ atomic_long_t num_poisoned_pages __read_
static bool __page_handle_poison(struct page *page)
{
- bool ret;
+ int ret;
zone_pcp_disable(page_zone(page));
ret = dissolve_free_huge_page(page);
@@ -76,7 +76,7 @@ static bool __page_handle_poison(struct
ret = take_page_off_buddy(page);
zone_pcp_enable(page_zone(page));
- return ret;
+ return ret > 0;
}
static bool page_handle_poison(struct page *page, bool hugepage_or_freepage, bool release)
_
Patches currently in -mm which might be from yun.wang@xxxxxxxxxxxxxxxxx are
mm-fix-panic-caused-by-__page_handle_poison.patch
