File gdb-testsuite-fix-possible-tcl-errors-in-gdb.threads.patch of Package gdb

From 4596ae47782b249e4989e136632037b1cef0fcb5 Mon Sep 17 00:00:00 2001
From: Guinevere Larsen <guinevere@redhat.com>
Date: Mon, 1 Sep 2025 11:48:30 -0300
Subject: [PATCH 22/25] gdb/testsuite: fix possible TCL errors in
 gdb.threads/threadcrash.exp

The test gdb.threads/threadcrash.exp, among other things, creates a list
of the threads seen in the order that the "thread apply all backtrace"
would generate them, tests that this list is the same size as GDB's
count of threads, and then loops over the list to check that each
thread has the expected backtrace.

A problem occurs because the loop iterates on GDB's internal count of
threads, rather than the size of the list, but then attempts to acces
the n-th element of the list. If the list size is smaller than GDB's
internal thread count, it'll access past the end of the list and
generate TCL errors.

This commit fixes this by using the list's length instead.

Approved-By: Tom Tromey <tom@tromey.com>
---
 gdb/testsuite/gdb.threads/threadcrash.exp | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/gdb/testsuite/gdb.threads/threadcrash.exp b/gdb/testsuite/gdb.threads/threadcrash.exp
index 6da70736983..9da3bda2a3c 100644
--- a/gdb/testsuite/gdb.threads/threadcrash.exp
+++ b/gdb/testsuite/gdb.threads/threadcrash.exp
@@ -132,8 +132,9 @@ proc do_full_test {} {
 	set pthread_kill ".*"
     }
 
-    for {set i 0} {$i < $thread_count } {incr i} {
-	set thread_num [expr [llength $test_list] - $i]
+    set loop_iterations [llength $test_list]
+    for {set i 0} {$i < $loop_iterations } {incr i} {
+	set thread_num [expr $loop_iterations - $i]
 
 	set type [lindex $test_list $i]
 	if { $type == 1 } {
-- 
2.51.0