mysqld crash at Dir_Walker::is_directory for debug builds

[meetamit77]

Seems to be a problem with debug builds. Release builds work fine, also crashes with mysql 8.0.44 debug builds.

If a directory contains file extension .traineddata which indicates a Trained Data Archive used by Tesseract OCR, an open-source optical character recognition engine, then specifying the directory as --innodb_directories in the startup command crashes the server.

Download the data from https://github.com/tesseract-ocr/tessdata_fast
Initialize the datadir and then try to use the startup command for starting the mysqld server as shown below

./bin/mysqld --datadir=~/data5 --lower_case_table_names=1 --initialize-insecure --default-authentication-plugin=mysql_native_password

./bin/mysqld --datadir=~/data5 --socket=/tmp/mysql.sock --port=3306 --core-file --lower_case_table_names=1 --innodb_directories='~/tessdata_fast-main'

#0 pthread_kill () from /lib64/libpthread.so.0
#1 my_write_core (sig=6) at mysql1/mysys/stacktrace.cc:344
#2 handle_fatal_signal (sig=6) at mysql1/sql/signal_handler.cc:232
#3
#4 raise () from /lib64/libc.so.6
#5 abort () from /lib64/libc.so.6
#6 my_server_abort () at mysql1/sql/signal_handler.cc:288
#7 my_abort () at mysql1/mysys/my_init.cc:264
#8 ut_dbg_assertion_failed (expr="exists", file="mysql1/storage/innobase/os/os0file.cc", line=7772) at mysql1/storage/innobase/ut/ut0dbg.cc:100
#9 Dir_Walker::is_directory (path="/tessdata_fast-main/configs") at mysql1/storage/innobase/os/os0file.cc:7772
#10 Dir_Walker::walk_posix(std::__cxx11::basic_string<char, std::char_traits, std::allocator > const&, bool, std::function<void (std::__cxx11::basic_string<char, std::char_traits, std::allocator > const&, unsigned long)>&&) (
basedir="/tessdata_fast-main/", recursive=true, f=...) at mysql1/storage/innobase/os/os0file.cc:3663

[meetamit77]

Not sure what is striking out a few of the information in the issue mentioned above

[p1p1bear]

Hi, @meetamit77

During MySQL data directory initialization, the specified datadir must be an empty directory. Otherwise, the initialization process may fail unexpectedly.

As you mentioned, in Debug mode the internal checks in MySQL are stricter, so this may trigger a crash. In this case, the crash is related to the logic that assumes the specified directory must already exist, as shown below:

/** Check if the path is a directory. The file/directory must exist.
@param[in]      path            The path to check
@return true if it is a directory */
bool Dir_Walker::is_directory(const Path &path) {
  os_file_type_t type;
  bool exists;

  if (os_file_status(path.c_str(), &exists, &type)) {
    ut_ad(exists);
    ut_ad(type != OS_FILE_TYPE_MISSING);

    return (type == OS_FILE_TYPE_DIR);
  }

  ut_ad(exists || type == OS_FILE_TYPE_FAILED);
  ut_ad(type != OS_FILE_TYPE_MISSING);

  return (false);
}

From the commands you provided:

./bin/mysqld --datadir=~/data5 --lower_case_table_names=1 --initialize-insecure --default-authentication-plugin=mysql_native_password

./bin/mysqld --datadir=/data5 --socket=/tmp/mysql.sock --port=3306 --core-file --lower_case_table_names=1 --innodb_directories='/tessdata_fast-main'

it looks like the data directory used during initialization is ~/data5 (that is, something like /home/.../data5), while during startup you are using /data5 under the root directory.

I suspect this mismatch may be the reason for the failure.

Could you please verify whether the same datadir is being used consistently for both initialization and startup?

Best regards :)

[meetamit77]

Something is messed up in the command I pasted, I am actually using ~/data5 during startup

./bin/mysqld --datadir=~/data5 --socket=/tmp/mysql.sock --port=3306 --core-file --lower_case_table_names=1 --innodb_directories='~/tessdata_fast-main'