• Bob Liu's avatar
    ramfs: fix memleak on no-mmu arch · b836aec5
    Bob Liu authored
    On no-mmu arch, there is a memleak during shmem test.  The cause of this
    memleak is ramfs_nommu_expand_for_mapping() added page refcount to 2
    which makes iput() can't free that pages.
    
    The simple test file is like this:
    
      int main(void)
      {
    	int i;
    	key_t k = ftok("/etc", 42);
    
    	for ( i=0; i<100; ++i) {
    		int id = shmget(k, 10000, 0644|IPC_CREAT);
    		if (id == -1) {
    			printf("shmget error\n");
    		}
    		if(shmctl(id, IPC_RMID, NULL ) == -1) {
    			printf("shm  rm error\n");
    			return -1;
    		}
    	}
    	printf("run ok...\n");
    	return 0;
      }
    
    And the result:
    
      root:/> free
                   total         used         free       shared      buffers
      Mem:         60320        17912        42408            0            0
      -/+ buffers:              17912        42408
      root:/> shmem
      run ok...
      root:/> free
                   total         used         free       shared      buffers
      Mem:         60320        19096        41224            0            0
      -/+ buffers:              19096        41224
      root:/> shmem
      run ok...
      root:/> free
                   total         used         free       shared      buffers
      Mem:         60320        20296        40024            0            0
      -/+ buffers:              20296        40024
      ...
    
    After this patch the test result is:(no memleak anymore)
    
      root:/> free
                   total         used         free       shared      buffers
      Mem:         60320        16668        43652            0            0
      -/+ buffers:              16668        43652
      root:/> shmem
      run ok...
      root:/> free
                   total         used         free       shared      buffers
      Mem:         60320        16668        43652            0            0
      -/+ buffers:              16668        43652
    Signed-off-by: default avatarBob Liu <lliubbo@gmail.com>
    Acked-by: default avatarHugh Dickins <hughd@google.com>
    Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
    Cc: <stable@kernel.org>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    b836aec5
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