• Hou Tao's avatar
    selftests/bpf: Add test cases for inner map · 1624918b
    Hou Tao authored
    Add test cases to test the race between the destroy of inner map due to
    map-in-map update and the access of inner map in bpf program. The
    following 4 combinations are added:
    (1) array map in map array + bpf program
    (2) array map in map array + sleepable bpf program
    (3) array map in map htab + bpf program
    (4) array map in map htab + sleepable bpf program
    
    Before applying the fixes, when running `./test_prog -a map_in_map`, the
    following error was reported:
    
      ==================================================================
      BUG: KASAN: slab-use-after-free in array_map_update_elem+0x48/0x3e0
      Read of size 4 at addr ffff888114f33824 by task test_progs/1858
    
      CPU: 1 PID: 1858 Comm: test_progs Tainted: G           O     6.6.0+ #7
      Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) ......
      Call Trace:
       <TASK>
       dump_stack_lvl+0x4a/0x90
       print_report+0xd2/0x620
       kasan_report+0xd1/0x110
       __asan_load4+0x81/0xa0
       array_map_update_elem+0x48/0x3e0
       bpf_prog_be94a9f26772f5b7_access_map_in_array+0xe6/0xf6
       trace_call_bpf+0x1aa/0x580
       kprobe_perf_func+0xdd/0x430
       kprobe_dispatcher+0xa0/0xb0
       kprobe_ftrace_handler+0x18b/0x2e0
       0xffffffffc02280f7
      RIP: 0010:__x64_sys_getpgid+0x1/0x30
      ......
       </TASK>
    
      Allocated by task 1857:
       kasan_save_stack+0x26/0x50
       kasan_set_track+0x25/0x40
       kasan_save_alloc_info+0x1e/0x30
       __kasan_kmalloc+0x98/0xa0
       __kmalloc_node+0x6a/0x150
       __bpf_map_area_alloc+0x141/0x170
       bpf_map_area_alloc+0x10/0x20
       array_map_alloc+0x11f/0x310
       map_create+0x28a/0xb40
       __sys_bpf+0x753/0x37c0
       __x64_sys_bpf+0x44/0x60
       do_syscall_64+0x36/0xb0
       entry_SYSCALL_64_after_hwframe+0x6e/0x76
    
      Freed by task 11:
       kasan_save_stack+0x26/0x50
       kasan_set_track+0x25/0x40
       kasan_save_free_info+0x2b/0x50
       __kasan_slab_free+0x113/0x190
       slab_free_freelist_hook+0xd7/0x1e0
       __kmem_cache_free+0x170/0x260
       kfree+0x9b/0x160
       kvfree+0x2d/0x40
       bpf_map_area_free+0xe/0x20
       array_map_free+0x120/0x2c0
       bpf_map_free_deferred+0xd7/0x1e0
       process_one_work+0x462/0x990
       worker_thread+0x370/0x670
       kthread+0x1b0/0x200
       ret_from_fork+0x3a/0x70
       ret_from_fork_asm+0x1b/0x30
    
      Last potentially related work creation:
       kasan_save_stack+0x26/0x50
       __kasan_record_aux_stack+0x94/0xb0
       kasan_record_aux_stack_noalloc+0xb/0x20
       __queue_work+0x331/0x950
       queue_work_on+0x75/0x80
       bpf_map_put+0xfa/0x160
       bpf_map_fd_put_ptr+0xe/0x20
       bpf_fd_array_map_update_elem+0x174/0x1b0
       bpf_map_update_value+0x2b7/0x4a0
       __sys_bpf+0x2551/0x37c0
       __x64_sys_bpf+0x44/0x60
       do_syscall_64+0x36/0xb0
       entry_SYSCALL_64_after_hwframe+0x6e/0x76
    Signed-off-by: default avatarHou Tao <houtao1@huawei.com>
    Link: https://lore.kernel.org/r/20231204140425.1480317-7-houtao@huaweicloud.comSigned-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
    1624918b
access_map_in_map.c 1.88 KB