Comment 2 for bug 1979923

Thanks for reporting this bug and trying to make Ubuntu better.

Checking the logs I found this stacktrace:

01:00:28 UTC - mysqld got signal 11 ;
Most likely, you have hit a bug, but this error can also be caused by malfunctioning hardware.
Thread pointer: 0x562e12ba3a30
Attempting backtrace. You can use the following information to find out
where mysqld died. If you see no messages after this, something went
terribly wrong...
stack_bottom = 7f850bbc9ce0 thread_stack 0x100000
/usr/sbin/mysqld(my_print_stacktrace(unsigned char const*, unsigned long)+0x41) [0x562e0e206ad1]
/usr/sbin/mysqld(print_fatal_signal(int)+0x2fb) [0x562e0d0a77db]
/usr/sbin/mysqld(handle_fatal_signal+0xa5) [0x562e0d0a7895]
/lib/x86_64-linux-gnu/libpthread.so.0(+0x14420) [0x7f851af84420]
/usr/sbin/mysqld(dd::sdi::store(THD*, dd::Table const*)+0xd0) [0x562e0df73350]
/usr/sbin/mysqld(dd::upgrade_57::add_sdi_info(THD*)+0xb00) [0x562e0e1d6490]
/usr/sbin/mysqld(dd::upgrade_57::do_pre_checks_and_initialize_dd(THD*)+0xeda) [0x562e0e1da17a]
/usr/sbin/mysqld(+0x11f6d86) [0x562e0d16cd86]
/usr/sbin/mysqld(+0x27e1bcd) [0x562e0e757bcd]
/lib/x86_64-linux-gnu/libpthread.so.0(+0x8609) [0x7f851af78609]
/lib/x86_64-linux-gnu/libc.so.6(clone+0x43) [0x7f851a1c8133]

As the message says this might be a hardware issue, make sure everything is working fine.

I also found multiple occurrences of this in the kernel log:

[19834.502038] audit: type=1400 audit(1656291628.048:273): apparmor="DENIED" operation="open" profile="/usr/sbin/mysqld" name="/proc/69410/task/69411/mem" pid=69410 comm="boot" requested_mask="r" denied_mask="r" fsuid=121 ouid=121

So apparmor is denying this "open" operation which might be causing the crash. I took a look at the package changes in Focal and the apparmor rules have not been changed for a while, so I do not think this might be a regression.

Could you check some warning messages in your dmesg output and make sure there is no hardware issue?

I am setting the status of this bug to Incomplete, once you provided the requested info set it back to New and we will take a look again.