[PULL 05/21] scripts/qemugdb: coroutine: Fix selected frame leak on error path

[Kevin Wolf <kwolf@redhat.com>]

From: Andrey Drobyshev <andrey.drobyshev@virtuozzo.com>

Currently, whenever gdb.execute() fails and throws an exception,
previously selected frame gets leaked.  I.e.:

  (gdb) frame N
  (gdb) qemu bt # throws exception
  (gdb) frame   # shows 0, not N

As a fix, wrap gdb.execute() commands in try/finally, so that selected
frame gets restored no matter what.

Fixes: 4cbf8efc5b89 ("scripts/gdb: fix 'qemu coroutine' when users selects a non topmost stack frame")
Signed-off-by: Andrey Drobyshev <andrey.drobyshev@virtuozzo.com>
Message-ID: <20260804151743.937694-2-andrey.drobyshev@virtuozzo.com>
Tested-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 scripts/qemugdb/coroutine.py | 23 +++++++++++++----------
 1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/scripts/qemugdb/coroutine.py b/scripts/qemugdb/coroutine.py
index 29f57ae84ed..d1e6722d14d 100644
--- a/scripts/qemugdb/coroutine.py
+++ b/scripts/qemugdb/coroutine.py
@@ -265,18 +265,21 @@ def dump_backtrace_live(regs):
     selected_frame = gdb.selected_frame()
     gdb.newest_frame().select()
 
-    for i in regs:
-        old[i] = gdb.parse_and_eval('(uint64_t)$%s' % i)
-
-    for i in regs:
-        gdb.execute('set $%s = %s' % (i, regs[i]))
-
-    gdb.execute('bt')
+    try:
+        for i in regs:
+            old[i] = gdb.parse_and_eval('(uint64_t)$%s' % i)
 
-    for i in regs:
-        gdb.execute('set $%s = %s' % (i, old[i]))
+        for i in regs:
+            gdb.execute('set $%s = %s' % (i, regs[i]))
 
-    selected_frame.select()
+        gdb.execute('bt')
+    finally:
+        try:
+            for i in old:
+                gdb.execute('set $%s = %s' % (i, old[i]))
+        finally:
+            # restore previously selected frame in any case
+            selected_frame.select()
 
 def bt_jmpbuf(jmpbuf, detailed=False):
     '''Backtrace a jmpbuf'''
-- 
2.56.0