unicode: Fix utf8_load() error path

utf8_load() requests the symbol "utf8_data_table" and then checks if the
requested UTF-8 version is supported. If it's unsupported, it tries to
put the data table using symbol_put(). If an unsupported version is
requested, symbol_put() fails like this:

 kernel BUG at kernel/module/main.c:786!
 RIP: 0010:__symbol_put+0x93/0xb0
 Call Trace:
  <TASK>
  ? __die_body.cold+0x19/0x27
  ? die+0x2e/0x50
  ? do_trap+0xca/0x110
  ? do_error_trap+0x65/0x80
  ? __symbol_put+0x93/0xb0
  ? exc_invalid_op+0x51/0x70
  ? __symbol_put+0x93/0xb0
  ? asm_exc_invalid_op+0x1a/0x20
  ? __pfx_cmp_name+0x10/0x10
  ? __symbol_put+0x93/0xb0
  ? __symbol_put+0x62/0xb0
  utf8_load+0xf8/0x150

That happens because symbol_put() expects the unique string that
identify the symbol, instead of a pointer to the loaded symbol. Fix that
by using such string.

Fixes: 2b3d047 ("unicode: Add utf8-data module")
Signed-off-by: André Almeida <[email protected]>
Reviewed-by: Theodore Ts'o <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Gabriel Krisman Bertazi <[email protected]>

Author: andrealmeid

fs/unicode/utf8-core.c

@@ -198,7 +198,7 @@ struct unicode_map *utf8_load(unsigned int version)
 	return um;
 
 out_symbol_put:
-	symbol_put(um->tables);
+	symbol_put(utf8_data_table);
 out_free_um:
 	kfree(um);
 	return ERR_PTR(-EINVAL);