Re: [PATCH] gdb/testsuite: fix race in gdb.server/multi-ui-errors.exp

[Andrew Burgess <aburgess@redhat.com>]

Tom de Vries <tdevries@suse.de> writes:

> On 5/24/23 18:29, Andrew Burgess wrote:
>> After this commit:
>> 
>>    commit ed32754a8c7919feffc6ddb66ff1c532e4a4d1cd
>>    Date:   Thu Mar 9 10:45:03 2023 +0100
>> 
>>        [gdb/testsuite] Fix gdb.server/multi-ui-errors.exp for remote target
>> 
>> I noticed the occasional failure in gdb.server/multi-ui-errors.exp,
>> which looked like this:
>> 
>>    (gdb) PASS: gdb.server/multi-ui-errors.exp: interact with GDB's main UI
>>    interrupt
>>    (gdb)
>>    Program received signal SIGINT, Interrupt.
>>    0x00007ffff7d501e7 in nanosleep () from /lib64/libc.so.6
>>    FAIL: gdb.server/multi-ui-errors.exp: interrupt (timeout)
>>    PASS: gdb.server/multi-ui-errors.exp: interrupt arrived
>>    p server_pid
>>    $1 = 718174
>>    (gdb) PASS: gdb.server/multi-ui-errors.exp: p server_pid
>> 
>> This is triggered by this code in gdb.server/multi-ui-errors.exp:
>> 
>>      gdb_test "interrupt"
>> 
>>      gdb_test_multiple "" "interrupt arrived" {
>> 	-re "Program received signal SIGINT, Interrupt\\.\r\n" {
>> 	    pass $gdb_test_name
>> 	}
>>      }
>> 
>> The problem here is that the first interrupt will trigger the prompt
>> to be printed, and then, after some time the inferior will be
>> interrupted.
>> 
>> However the default pattern for gdb_test includes a '$' end anchor.
>> If expect see the prompt with nothing following it then everything is
>
> Hi Andrew,
>
> see -> sees
>
>> fine, and the test passes.
>> 
>> However, if the interrupt is quick and so what expect sees is this:
>> 
>>    (gdb)
>>    Program received signal SIGINT, Interrupt.
>>    0x00007ffff7d501e7 in nanosleep () from /lib64/libc.so.6
>> 
>> In this case the end anchor means that the gdb_test fails to match,
>> and eventually times out.
>> 
>> Fix this by passing -no-prompt-anchor to gdb_test.
>
> thanks for fixing this.
>
> LGTM.
>
> Reviewed-by: Tom de Vries <tdevries@suse.de>

Pushed (with typo fixed).

Thanks,
Andrew

>
> Thanks,
> - Tom
>
>
>> ---
>>   gdb/testsuite/gdb.server/multi-ui-errors.exp | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>> 
>> diff --git a/gdb/testsuite/gdb.server/multi-ui-errors.exp b/gdb/testsuite/gdb.server/multi-ui-errors.exp
>> index af83614fe55..47ded35bc86 100644
>> --- a/gdb/testsuite/gdb.server/multi-ui-errors.exp
>> +++ b/gdb/testsuite/gdb.server/multi-ui-errors.exp
>> @@ -106,7 +106,7 @@ with_spawn_id $gdb_main_spawn_id {
>>   # Get the gdbserver PID.
>>   set gdbserver_pid 0
>>   with_spawn_id $gdb_main_spawn_id {
>> -    gdb_test "interrupt"
>> +    gdb_test -no-prompt-anchor "interrupt"
>>   
>>       gdb_test_multiple "" "interrupt arrived" {
>>   	-re "Program received signal SIGINT, Interrupt\\.\r\n" {
>> 
>> base-commit: 389971df23ca74092314dbde1303310a33766ba7