mm: fix panic caused by __page_handle_poison()
authorMichael Wang <yun.wang@linux.alibaba.com>
Thu, 2 Sep 2021 21:58:40 +0000 (14:58 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 3 Sep 2021 16:58:16 +0000 (09:58 -0700)
commitf87060d345232c7d855167a43faf006e24afa999
treec19688b957a573a3b742d415b3f28b89781922be
parent941ca063eb8ed01e66336b1f493e95b107024bc8
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@linux.alibaba.com
Fixes: 510d25c92ec4 ("mm/hwpoison: disable pcp for page_handle_poison()")
Signed-off-by: Michael Wang <yun.wang@linux.alibaba.com>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Reported-by: Abaci <abaci@linux.alibaba.com>
Cc: <stable@vger.kernel.org> [5.14+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/memory-failure.c