Firebird 3 crash - Access violation

[EPluribusUnum]

Hi *!

" Access violation. The code attempted to access a virtual address without privilege to do so. This exception will cause the Firebird server to terminate abnormally."

The dump was created with Firebird-3.0.11.33665-0_x64.zip

I'll send FTP details of the dump in PM.

[hvlad]

Send it to me, pls

[EPluribusUnum]

@hvlad , email sent.

[hvlad]

Downloaded, thanks. Investigating. If you could produce a test case - it would help a lot.

[EPluribusUnum]

@hvlad , database uploaded.

Run this 4 SQL parallel in 4 connection.

execute procedure rep_fk_tabla(100044372, 'ABC', 4, 0) execute procedure rep_fk_tabla(100044372, 'ABC', 4, 1) execute procedure rep_fk_tabla(100044372, 'ABC', 4, 2) execute procedure rep_fk_tabla(100044372, 'ABC', 4, 3)

[hvlad]

I run these queries in parallel many times (on the fresh copy of DB every time) and get no crash. Results are pretty consistent - one query succeeds, three other fails with

Statement failed, SQLSTATE = 42000 Dynamic SQL Error -SQL error code = -104 -Unexpected end of command - line 1, column 1 -At block line: 38, col: 9 -At procedure 'REP_FK_TABLA' line: 87, col: 3

It happens because of attempt to run empty query using EXECUTE STATEMENT.

BTW, it requires UDF library UDF3s.dll and I found some but it could be outdated (29.05.2012)

[EPluribusUnum]

@hvlad , I uploaded

• a new database
• new commandt to test with
• complete Firebird directory
• 2 new crash dumps

run the command on snapshot

[hvlad]

No luck :( Now all 4 statements run successfully for ~320 sec each, one of them returns

TRAN_START	SQL_SELECT	SQL_DELETE	WAIT_AND_REPEAT
28-FEB-2023	<null>	<null>	<null>

while other 3 have value 1000 in WAIT_AND_REPEAT column

[EPluribusUnum]

Now I I get a crash for a single SQL command. Uploaded a new database, the complete Firebird directory (v3.0.10.33601) and a new crash dump.

execute procedure rep_fk_tabla(100046633, 'LIBRA3S')

[EPluribusUnum]

Looks like the issue is around exception handling.

In FK_TABLA_CALC_CELL_ALLOC function when I add an EXISTS precheck, no crash happens.

CREATE OR ALTER FUNCTION fk_tabla_calc_cell_alloc ( rpt_report_job_id xidn, cell_addr TYPE OF COLUMN fk_tabla_calc.cell_addr, thread_index TYPE OF COLUMN fk_tabla_calc.thread_index) RETURNS BOOLEAN AS BEGIN --IF (EXISTS(SELECT * FROM fk_tabla_calc c WHERE c.rpt_report_job_id = :rpt_report_job_id AND c.cell_addr = :cell_addr)) --THEN RETURN FALSE; BEGIN INSERT INTO fk_tabla_calc (rpt_report_job_id, cell_addr, thread_index) VALUES (:rpt_report_job_id, :cell_addr, :thread_index); RETURN TRUE; WHEN GDSCODE unique_key_violation DO BEGIN RETURN FALSE; END END END

[EPluribusUnum]

Note: the EXISTS check workaround is only usabe when I run the rep_fk_tabla procedure in a single thread. When I run it multiple times in parallel on snapshot transactions the EXISTS check does not help, the only soution is the exception handling.

[dyemanov]

What if you change the exception handler to just set some return flag and do RETURN RES;in the end of the function?

[hvlad]

Reproduced, thanks.

@dyemanov yes, it helps, no crash

[EPluribusUnum]

Confirmed, returning outside the exception block is a good workaround to avoid the crash.

[omachtandras]

Simplified test case with employee.fdb

create package die as begin function is_integer(s varchar(10)) returns boolean; end

create package body die as begin function is_integer(s varchar(10)) returns boolean as declare variable i integer; begin begin i = cast(s as integer); when any do begin return false; end end return true; end end

create or alter procedure GET_PROJECT_ID returns ( ID type of column PROJECT.PROJ_ID) as begin id = null; if (die.is_integer('1A1')) then begin id = 'INT'; end suspend; end

create or alter procedure INSERT_PROJECT as declare variable id type of column project.proj_id; begin select id from get_project_id into :id;

insert into PROJECT (PROJ_ID, PROJ_NAME, PRODUCT) values (:ID, 'NAME', 'SIMPLE'); end

FB 3.0.11: connection dies Unsuccessful execution caused by a system error.... Error reading data from the connection.

FB 4.0.3 and 5.0.0 RC1 works fine: validation error for column "PROJECT"."PROJ_ID", value " null ". At procedure INSERT_PROJECT line: 9, col: 3.

SQLCODE: -625 SQLSTATE: 23000 GDSCODE: 335544347