Hi Rafael,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on linux-sof-driver/master]
[also build test WARNING on v4.19 next-20181019]
[if your patch is applied to the wrong git tree, please drop us a note to help 
improve the system]

url:    
https://github.com/0day-ci/linux/commits/Rafael-David-Tinoco/mm-zsmalloc-c-check-encoded-object-value-overflow-for-PAE/20181025-110258
base:   https://github.com/thesofproject/linux master
config: um-allyesconfig (attached as .config)
compiler: gcc-7 (Debian 7.3.0-1) 7.3.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=um 

All warnings (new ones prefixed by >>):

   In file included from include/linux/kernel.h:10:0,
                    from include/linux/list.h:9,
                    from include/linux/module.h:9,
                    from mm/zsmalloc.c:33:
   mm/zsmalloc.c: In function 'location_to_obj':
>> mm/zsmalloc.c:129:17: warning: left shift count >= width of type 
>> [-Wshift-count-overflow]
     ((_AC(1, ULL)) << MAX_POSSIBLE_PHYSMEM_BITS) ? 1 : 0)
                    ^
   include/linux/compiler.h:77:42: note: in definition of macro 'unlikely'
    # define unlikely(x) __builtin_expect(!!(x), 0)
                                             ^
>> mm/zsmalloc.c:886:15: note: in expansion of macro 'OBJ_OVERFLOW'
     if (unlikely(OBJ_OVERFLOW(pfn)))
                  ^~~~~~~~~~~~
   Cyclomatic Complexity 5 include/linux/compiler.h:__read_once_size
   Cyclomatic Complexity 5 include/linux/compiler.h:__write_once_size
   Cyclomatic Complexity 1 include/linux/kasan-checks.h:kasan_check_read
   Cyclomatic Complexity 1 include/linux/kasan-checks.h:kasan_check_write
   Cyclomatic Complexity 2 arch/x86/include/asm/bitops.h:set_bit
   Cyclomatic Complexity 2 arch/x86/include/asm/bitops.h:clear_bit
   Cyclomatic Complexity 1 arch/x86/include/asm/bitops.h:clear_bit_unlock
   Cyclomatic Complexity 1 arch/x86/include/asm/bitops.h:test_and_set_bit
   Cyclomatic Complexity 1 arch/x86/include/asm/bitops.h:test_and_set_bit_lock
   Cyclomatic Complexity 1 arch/x86/include/asm/bitops.h:constant_test_bit
   Cyclomatic Complexity 1 arch/x86/include/asm/bitops.h:variable_test_bit
   Cyclomatic Complexity 1 arch/x86/include/asm/bitops.h:fls64
   Cyclomatic Complexity 1 include/linux/log2.h:__ilog2_u64
   Cyclomatic Complexity 1 include/linux/kernel.h:___might_sleep
   Cyclomatic Complexity 1 include/linux/list.h:INIT_LIST_HEAD
   Cyclomatic Complexity 2 include/linux/list.h:__list_add
   Cyclomatic Complexity 1 include/linux/list.h:list_add
   Cyclomatic Complexity 1 include/linux/list.h:__list_del
   Cyclomatic Complexity 2 include/linux/list.h:__list_del_entry
   Cyclomatic Complexity 1 include/linux/list.h:list_del
   Cyclomatic Complexity 1 include/linux/list.h:list_del_init
   Cyclomatic Complexity 1 include/linux/list.h:list_empty
   Cyclomatic Complexity 1 include/linux/list.h:__list_splice
   Cyclomatic Complexity 2 include/linux/list.h:list_splice_init
   Cyclomatic Complexity 1 arch/um/include/shared/mem.h:to_virt
   Cyclomatic Complexity 1 include/asm-generic/getorder.h:__get_order
   Cyclomatic Complexity 1 arch/um/include/asm/thread_info.h:current_thread_info
   Cyclomatic Complexity 1 include/asm-generic/preempt.h:preempt_count
   Cyclomatic Complexity 1 arch/x86/include/asm/atomic.h:arch_atomic_read
   Cyclomatic Complexity 1 arch/x86/include/asm/atomic.h:arch_atomic_set
   Cyclomatic Complexity 1 arch/x86/include/asm/atomic.h:arch_atomic_inc
   Cyclomatic Complexity 1 
arch/x86/include/asm/atomic.h:arch_atomic_dec_and_test
   Cyclomatic Complexity 1 arch/x86/include/asm/atomic64_64.h:arch_atomic64_read
   Cyclomatic Complexity 1 arch/x86/include/asm/atomic64_64.h:arch_atomic64_add
   Cyclomatic Complexity 1 arch/x86/include/asm/atomic64_64.h:arch_atomic64_sub
   Cyclomatic Complexity 1 arch/x86/include/asm/atomic64_64.h:arch_atomic64_inc
   Cyclomatic Complexity 1 arch/x86/include/asm/atomic64_64.h:arch_atomic64_dec
   Cyclomatic Complexity 1 include/asm-generic/atomic-instrumented.h:atomic_read
   Cyclomatic Complexity 1 
include/asm-generic/atomic-instrumented.h:atomic64_read
   Cyclomatic Complexity 1 include/asm-generic/atomic-instrumented.h:atomic_set
   Cyclomatic Complexity 1 include/asm-generic/atomic-instrumented.h:atomic_inc
   Cyclomatic Complexity 1 
include/asm-generic/atomic-instrumented.h:atomic64_inc
   Cyclomatic Complexity 1 
include/asm-generic/atomic-instrumented.h:atomic64_dec
   Cyclomatic Complexity 1 
include/asm-generic/atomic-instrumented.h:atomic64_add
   Cyclomatic Complexity 1 
include/asm-generic/atomic-instrumented.h:atomic64_sub
   Cyclomatic Complexity 1 
include/asm-generic/atomic-instrumented.h:atomic_dec_and_test
   Cyclomatic Complexity 1 include/asm-generic/atomic-long.h:atomic_long_read
   Cyclomatic Complexity 1 include/asm-generic/atomic-long.h:atomic_long_inc
   Cyclomatic Complexity 1 include/asm-generic/atomic-long.h:atomic_long_dec
   Cyclomatic Complexity 1 include/asm-generic/atomic-long.h:atomic_long_add
   Cyclomatic Complexity 1 include/asm-generic/atomic-long.h:atomic_long_sub
   Cyclomatic Complexity 1 arch/x86/um/asm/processor.h:rep_nop
   Cyclomatic Complexity 1 include/linux/spinlock.h:spinlock_check
   Cyclomatic Complexity 1 include/linux/spinlock.h:spin_lock
   Cyclomatic Complexity 1 include/linux/spinlock.h:spin_unlock
   Cyclomatic Complexity 1 include/linux/jump_label.h:static_key_count
   Cyclomatic Complexity 2 include/linux/jump_label.h:static_key_false
   Cyclomatic Complexity 1 include/linux/nodemask.h:node_state
   Cyclomatic Complexity 1 include/linux/err.h:PTR_ERR
   Cyclomatic Complexity 1 include/linux/err.h:IS_ERR
   Cyclomatic Complexity 1 include/linux/workqueue.h:queue_work
   Cyclomatic Complexity 1 include/linux/workqueue.h:schedule_work
   Cyclomatic Complexity 1 include/linux/topology.h:numa_node_id
   Cyclomatic Complexity 1 include/linux/topology.h:numa_mem_id
   Cyclomatic Complexity 1 include/linux/gfp.h:__alloc_pages
   Cyclomatic Complexity 4 include/linux/gfp.h:__alloc_pages_node
   Cyclomatic Complexity 2 include/linux/gfp.h:alloc_pages_node
   Cyclomatic Complexity 4 include/linux/bit_spinlock.h:bit_spin_lock
   Cyclomatic Complexity 2 include/linux/bit_spinlock.h:bit_spin_trylock
   Cyclomatic Complexity 2 include/linux/bit_spinlock.h:bit_spin_unlock
   Cyclomatic Complexity 2 include/linux/bit_spinlock.h:bit_spin_is_locked
   Cyclomatic Complexity 1 include/linux/fs.h:mount_pseudo
   Cyclomatic Complexity 2 include/linux/page-flags.h:compound_head
   Cyclomatic Complexity 1 include/linux/page-flags.h:PagePoisoned
   Cyclomatic Complexity 1 include/linux/page-flags.h:PageLocked
   Cyclomatic Complexity 1 include/linux/page-flags.h:PagePrivate
   Cyclomatic Complexity 1 include/linux/page-flags.h:SetPagePrivate
   Cyclomatic Complexity 1 include/linux/page-flags.h:ClearPagePrivate
   Cyclomatic Complexity 1 include/linux/page-flags.h:PageOwnerPriv1
   Cyclomatic Complexity 1 include/linux/page-flags.h:SetPageOwnerPriv1
   Cyclomatic Complexity 1 include/linux/page-flags.h:ClearPageOwnerPriv1
   Cyclomatic Complexity 1 include/linux/page-flags.h:PageIsolated
   Cyclomatic Complexity 1 include/linux/page_ref.h:page_ref_count
   Cyclomatic Complexity 2 include/linux/page_ref.h:page_ref_inc
   Cyclomatic Complexity 2 include/linux/page_ref.h:page_ref_dec_and_test
   Cyclomatic Complexity 1 include/linux/mm.h:put_page_testzero
   Cyclomatic Complexity 1 include/linux/mm.h:page_mapcount_reset
   Cyclomatic Complexity 1 include/linux/mm.h:page_zonenum
   Cyclomatic Complexity 1 include/linux/mm.h:get_page
   Cyclomatic Complexity 2 include/linux/mm.h:put_page
   Cyclomatic Complexity 1 include/linux/mm.h:page_zone
   Cyclomatic Complexity 1 include/linux/vmstat.h:__inc_zone_state
   Cyclomatic Complexity 1 include/linux/vmstat.h:__dec_zone_state
   Cyclomatic Complexity 1 include/linux/vmstat.h:__inc_zone_page_state
   Cyclomatic Complexity 1 include/linux/vmstat.h:__dec_zone_page_state
   Cyclomatic Complexity 1 include/linux/mm.h:lowmem_page_address
   Cyclomatic Complexity 1 include/linux/uaccess.h:pagefault_disabled_inc
   Cyclomatic Complexity 1 include/linux/uaccess.h:pagefault_disabled_dec

vim +129 mm/zsmalloc.c

    32  
  > 33  #include <linux/module.h>
    34  #include <linux/kernel.h>
    35  #include <linux/sched.h>
    36  #include <linux/magic.h>
    37  #include <linux/bitops.h>
    38  #include <linux/errno.h>
    39  #include <linux/highmem.h>
    40  #include <linux/string.h>
    41  #include <linux/slab.h>
    42  #include <asm/tlbflush.h>
    43  #include <asm/pgtable.h>
    44  #include <linux/cpumask.h>
    45  #include <linux/cpu.h>
    46  #include <linux/vmalloc.h>
    47  #include <linux/preempt.h>
    48  #include <linux/spinlock.h>
    49  #include <linux/shrinker.h>
    50  #include <linux/types.h>
    51  #include <linux/debugfs.h>
    52  #include <linux/zsmalloc.h>
    53  #include <linux/zpool.h>
    54  #include <linux/mount.h>
    55  #include <linux/migrate.h>
    56  #include <linux/pagemap.h>
    57  #include <linux/fs.h>
    58  
    59  #define ZSPAGE_MAGIC    0x58
    60  
    61  /*
    62   * This must be power of 2 and greater than of equal to 
sizeof(link_free).
    63   * These two conditions ensure that any 'struct link_free' itself 
doesn't
    64   * span more than 1 page which avoids complex case of mapping 2 pages 
simply
    65   * to restore link_free pointer values.
    66   */
    67  #define ZS_ALIGN                8
    68  
    69  /*
    70   * A single 'zspage' is composed of up to 2^N discontiguous 0-order 
(single)
    71   * pages. ZS_MAX_ZSPAGE_ORDER defines upper limit on N.
    72   */
    73  #define ZS_MAX_ZSPAGE_ORDER 2
    74  #define ZS_MAX_PAGES_PER_ZSPAGE (_AC(1, UL) << ZS_MAX_ZSPAGE_ORDER)
    75  
    76  #define ZS_HANDLE_SIZE (sizeof(unsigned long))
    77  
    78  /*
    79   * Object location (<PFN>, <obj_idx>) is encoded as
    80   * as single (unsigned long) handle value.
    81   *
    82   * Note that object index <obj_idx> starts from 0.
    83   *
    84   * This is made more complicated by various memory models and PAE.
    85   */
    86  
    87  #ifndef MAX_POSSIBLE_PHYSMEM_BITS
    88  #ifdef MAX_PHYSMEM_BITS
    89  #define MAX_POSSIBLE_PHYSMEM_BITS MAX_PHYSMEM_BITS
    90  #else
    91  /*
    92   * If this definition of MAX_PHYSMEM_BITS is used, OBJ_INDEX_BITS will 
just
    93   * be PAGE_SHIFT
    94   */
    95  #define MAX_POSSIBLE_PHYSMEM_BITS BITS_PER_LONG
    96  #endif
    97  #endif
    98  
    99  #define _PFN_BITS               (MAX_POSSIBLE_PHYSMEM_BITS - PAGE_SHIFT)
   100  
   101  /*
   102   * Memory for allocating for handle keeps object position by
   103   * encoding <page, obj_idx> and the encoded value has a room
   104   * in least bit(ie, look at obj_to_location).
   105   * We use the bit to synchronize between object access by
   106   * user and migration.
   107   */
   108  #define HANDLE_PIN_BIT  0
   109  
   110  /*
   111   * Head in allocated object should have OBJ_ALLOCATED_TAG
   112   * to identify the object was allocated or not.
   113   * It's okay to add the status bit in the least bit because
   114   * header keeps handle which is 4byte-aligned address so we
   115   * have room for two bit at least.
   116   */
   117  #define OBJ_ALLOCATED_TAG 1
   118  #define OBJ_TAG_BITS 1
   119  #define OBJ_INDEX_BITS  (BITS_PER_LONG - _PFN_BITS - OBJ_TAG_BITS)
   120  #define OBJ_INDEX_MASK  ((_AC(1, UL) << OBJ_INDEX_BITS) - 1)
   121  
   122  /*
   123   * When using PAE, the obj encoding might overflow if arch does
   124   * not re-define MAX_PHYSMEM_BITS, since zsmalloc uses HIGHMEM.
   125   * This checks for a future bad page access, when de-coding obj.
   126   */
   127  #define OBJ_OVERFLOW(_pfn) \
   128          (((unsigned long long) _pfn << (OBJ_INDEX_BITS + OBJ_TAG_BITS)) 
>= \
 > 129          ((_AC(1, ULL)) << MAX_POSSIBLE_PHYSMEM_BITS) ? 1 : 0)
   130  

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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