• Andrey Ryabinin's avatar
    kernel/memremap, kasan: make ZONE_DEVICE with work with KASAN · 0207df4f
    Andrey Ryabinin authored
    KASAN learns about hotadded memory via the memory hotplug notifier.
    devm_memremap_pages() intentionally skips calling memory hotplug
    notifiers.  So KASAN doesn't know anything about new memory added by
    devm_memremap_pages().  This causes a crash when KASAN tries to access
    non-existent shadow memory:
    
     BUG: unable to handle kernel paging request at ffffed0078000000
     RIP: 0010:check_memory_region+0x82/0x1e0
     Call Trace:
      memcpy+0x1f/0x50
      pmem_do_bvec+0x163/0x720
      pmem_make_request+0x305/0xac0
      generic_make_request+0x54f/0xcf0
      submit_bio+0x9c/0x370
      submit_bh_wbc+0x4c7/0x700
      block_read_full_page+0x5ef/0x870
      do_read_cache_page+0x2b8/0xb30
      read_dev_sector+0xbd/0x3f0
      read_lba.isra.0+0x277/0x670
      efi_partition+0x41a/0x18f0
      check_partition+0x30d/0x5e9
      rescan_partitions+0x18c/0x840
      __blkdev_get+0x859/0x1060
      blkdev_get+0x23f/0x810
      __device_add_disk+0x9c8/0xde0
      pmem_attach_disk+0x9a8/0xf50
      nvdimm_bus_probe+0xf3/0x3c0
      driver_probe_device+0x493/0xbd0
      bus_for_each_drv+0x118/0x1b0
      __device_attach+0x1cd/0x2b0
      bus_probe_device+0x1ac/0x260
      device_add+0x90d/0x1380
      nd_async_device_register+0xe/0x50
      async_run_entry_fn+0xc3/0x5d0
      process_one_work+0xa0a/0x1810
      worker_thread+0x87/0xe80
      kthread+0x2d7/0x390
      ret_from_fork+0x3a/0x50
    
    Add kasan_add_zero_shadow()/kasan_remove_zero_shadow() - post mm_init()
    interface to map/unmap kasan_zero_page at requested virtual addresses.
    And use it to add/remove the shadow memory for hotplugged/unplugged
    device memory.
    
    Link: http://lkml.kernel.org/r/20180629164932.740-1-aryabinin@virtuozzo.com
    Fixes: 41e94a85 ("add devm_memremap_pages")
    Signed-off-by: default avatarAndrey Ryabinin <aryabinin@virtuozzo.com>
    Reported-by: default avatarDave Chinner <david@fromorbit.com>
    Reviewed-by: default avatarDan Williams <dan.j.williams@intel.com>
    Tested-by: default avatarDan Williams <dan.j.williams@intel.com>
    Cc: Dmitry Vyukov <dvyukov@google.com>
    Cc: Alexander Potapenko <glider@google.com>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    0207df4f
kasan.h 4.85 KB