linux-kernel - [PATCH v2] mm: fix panic caused by __page_handle

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <61782ac6-1e8a-4f6f-35e6-e94fce3b37f5@linux.alibaba.com>
Date:   Tue, 31 Aug 2021 17:37:49 +0800
From:   王贇 <yun.wang@...ux.alibaba.com>
To:     Naoya Horiguchi <naoya.horiguchi@....com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        "open list:HWPOISON MEMORY FAILURE HANDLING" <linux-mm@...ck.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: [PATCH v2] mm: fix panic caused by __page_handle_poison()

By 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 replace 'bool' with 'int' to handle RET_A correctly.

Fixes: 510d25c92ec4 ("mm/hwpoison: disable pcp for page_handle_poison()")
Cc: <stable@...r.kernel.org> # 5.14
Acked-by: Naoya Horiguchi <naoya.horiguchi@....com>
Reported-by: Abaci <abaci@...ux.alibaba.com>
Signed-off-by: Michael Wang <yun.wang@...ux.alibaba.com>
---
 mm/memory-failure.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 470400c..0fff717 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -68,7 +68,7 @@

 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 page *page)
 		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)
-- 
1.8.3.1