• Michael Wang's avatar
    mm: fix panic caused by __page_handle_poison() · dba814c6
    Michael Wang authored
    commit f87060d3 upstream.
    
    In commit 510d25c9 ("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
       huget...
    dba814c6
memory-failure.c 59 KB