Re: [PATCH v8 6/6] gdb/infrun: handle already-exited threads when attempting to stop

[Pedro Alves <pedro@palves.net>]

On 5/14/20 7:54 PM, Aktemur, Tankut Baris wrote:
> On Thursday, May 14, 2020 8:00 PM, Tom de Vries wrote:
>> On 13-05-2020 22:53, Pedro Alves via Gdb-patches wrote:
>>> +	set testpid($num) [get_integer_valueof "pid" -1]
>>
>> I'm running into:
>> ...
>> ERROR: tcl error sourcing
>> /data/gdb_versions/devel/src/gdb/testsuite/gdb.multi/multi-kill.exp.
>> ERROR: can't set "testpid(1)": variable isn't array
>>     while executing
>> "set testpid($num) [get_integer_valueof "pid" -1]"
> 
> I'm not able to reproduce this problem.  The test runs fine on my system
> with 58 expected passes and no failures.  Could it be related to the tcl
> version?

It's related to testcase run order, and the fact that global variables
can leak between testcases.

> 
> As a rough guess, could you try the patch below to initialize the array
> variable?
> 
> diff --git a/gdb/testsuite/gdb.multi/multi-kill.exp b/gdb/testsuite/gdb.multi/multi-kill.exp
> index ce6075045fc..a21f8a78b0d 100644
> --- a/gdb/testsuite/gdb.multi/multi-kill.exp
> +++ b/gdb/testsuite/gdb.multi/multi-kill.exp
> @@ -70,6 +70,7 @@ proc start_inferior {num} {
>  # Sufficient inferiors to make sure that at least some other inferior
>  # is killed while we're handling a killed event.
>  set NUM_INFS 10
> +array set testpid {}

That's not sufficient, because the variable can leak to other tests.
For example:

 $ runtest gdb.threads/check-libthread-db.exp gdb.multi/multi-kill.exp

 Running /home/pedro/gdb/binutils-gdb/src/gdb/testsuite/gdb.multi/multi-kill.exp ...
 Running /home/pedro/gdb/binutils-gdb/src/gdb/testsuite/gdb.threads/check-libthread-db.exp ...
 ERROR: tcl error sourcing /home/pedro/gdb/binutils-gdb/src/gdb/testsuite/gdb.threads/check-libthread-db.exp.
 ERROR: can't set "testpid": variable is array
     while executing
 "set testpid [spawn_id_get_pid $test_spawn_id]"
     ("uplevel" body line 8)

This works for me.

From 96aa00638e9a1201874e316ad53c38614da8cc04 Mon Sep 17 00:00:00 2001
From: Pedro Alves <palves@redhat.com>
Date: Thu, 14 May 2020 19:07:35 +0100
Subject: [PATCH] Fix global variable collision in gdb.multi/multi-kill.exp

gdb/testsuite/ChangeLog:
2020-05-14  Pedro Alves  <palves@redhat.com>

	* gdb.multi/multi-kill.exp: Wrap in namespace.
	(start_inferior): Add TESTPID parameter.  Use it instead of the
	testpid global.
	(top level): Define empty TESTPID array, and pass it down to
	start_inferior.
---
 gdb/testsuite/gdb.multi/multi-kill.exp | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/gdb/testsuite/gdb.multi/multi-kill.exp b/gdb/testsuite/gdb.multi/multi-kill.exp
index ce6075045fc..03bf8449cf8 100644
--- a/gdb/testsuite/gdb.multi/multi-kill.exp
+++ b/gdb/testsuite/gdb.multi/multi-kill.exp
@@ -39,11 +39,15 @@ save_vars { GDBFLAGS } {
     clean_restart ${binfile}
 }
 
+# Wrap the entire test in a namespace to avoid contaminating other tests.
+namespace eval $testfile {
+
 # Start inferior NUM and record its PID in the TESTPID array.
 
-proc start_inferior {num} {
+proc start_inferior {num testpid} {
     with_test_prefix "start_inferior $num" {
-	global testpid binfile srcfile
+	upvar $testpid tpid
+	global binfile srcfile
 
 	if {$num != 1} {
 	    gdb_test "add-inferior" "Added inferior .*" \
@@ -58,8 +62,8 @@ proc start_inferior {num} {
 	gdb_run_cmd
 	gdb_test "" ".*reakpoint .*, initialized .*${srcfile}.*" "run"
 
-	set testpid($num) [get_integer_valueof "pid" -1]
-	if {$testpid($num) == -1} {
+	set tpid($num) [get_integer_valueof "pid" -1]
+	if {$tpid($num) == -1} {
 	    return -1
 	}
 
@@ -71,8 +75,11 @@ proc start_inferior {num} {
 # is killed while we're handling a killed event.
 set NUM_INFS 10
 
+# The array holding each inferior's PID, indexed by inferior number.
+array set testpid {}
+
 for {set i 1} {$i <= $NUM_INFS} {incr i} {
-    if {[start_inferior $i] < 0} {
+    if {[start_inferior $i testpid] < 0} {
 	return -1
     }
 }
@@ -125,3 +132,5 @@ for {set i 2} {$i <= $NUM_INFS} {incr i} {
 	    "continue to SIGKILL"
     }
 }
+
+}

base-commit: a05575d39a5348bd9979fc09e658a03ff22722b9
-- 
2.14.5