Hi, Thejaka,

On Aug 03, Thejaka Amila J Kanewala via developers wrote:
> Hello,
>
> I am trying to build and run a thread sanitized mysqld binary. In the
> CMake configuration, I see the WITH_ASAN option, however, I do not see
> an option to build mysqld with the thread sanitizer.

What MariaDB version did you look at?
The earliest still supported is 10.4:

This is WITH_ASAN option:
https://github.com/MariaDB/server/blob/10.4/CMakeLists.txt#L199

This is WITH_TSAN option:
https://github.com/MariaDB/server/blob/10.4/CMakeLists.txt#L223

> After making some custom configurations, I was able to build a mysqld
> binary with the thread sanitizer (by linking static thread sanitizer),
> however, when trying to run it, I got the following error:
>
> "ThreadSanitizer: sync allocator overflow (65536*1024). Dying."
>
> This error seems to be coming from the tsan library and seems this error is
> caused by too many synchronizations [1]. Reducing the number of threads
> also didn't help me with this error.
>
> So my questions to you experts:
> 1. Do you run mysqld with the thread sanitizer ?

No, our CI only runs with ASAN, MSAN, and UBSAN.

> 2. If yes, could you please share the details. (e.g., CMake
> configurations, compiler/linker flags etc.)
> 3. If not, any suggestions to overcome the above error ?

See above. I've just built with -DWITH_TSAN=ON and didn't get that error
of yours. On gcc 12.3.1.

I did get a lot of

    warning: 'atomic_thread_fence' is not supported with '-fsanitize=thread'

which should've been expected, https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97868

And thread sanitizer was complaining about statistic_increment() macro,
which, indeed, increments a shared variable without any locks.
Intentionally, though.

Regards,
Sergei
VP of MariaDB Server Engineering
and security@mariadb.org