[Lldb-commits] [lldb] Fix a crash when a stop hook deletes itself in its callback. (PR #160416)
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lldb-commits at lists.llvm.org
Thu Nov 6 11:43:46 PST 2025
https://github.com/jimingham updated https://github.com/llvm/llvm-project/pull/160416
>From 76644944606ed28affc01d7638b99372ccac86f7 Mon Sep 17 00:00:00 2001
From: Jim Ingham <jingham at apple.com>
Date: Tue, 23 Sep 2025 13:44:33 -0700
Subject: [PATCH 1/3] Fix a crash when a stop hook deletes itself in its
callback.
---
lldb/source/Target/Target.cpp | 8 ++++-
.../target/stop-hooks/TestStopHookScripted.py | 33 +++++++++++++++++++
.../commands/target/stop-hooks/stop_hook.py | 24 ++++++++++++++
3 files changed, 64 insertions(+), 1 deletion(-)
diff --git a/lldb/source/Target/Target.cpp b/lldb/source/Target/Target.cpp
index fa98c24606492..e94fe854f8157 100644
--- a/lldb/source/Target/Target.cpp
+++ b/lldb/source/Target/Target.cpp
@@ -3171,7 +3171,13 @@ bool Target::RunStopHooks(bool at_initial_stop) {
bool should_stop = false;
bool requested_continue = false;
- for (auto stop_entry : m_stop_hooks) {
+ // A stop hook might get deleted while running stop hooks.
+ // We have to decide what that means. We will follow the rule that deleting
+ // a stop hook while processing these stop hooks will delete it for FUTURE
+ // stops but not this stop. The easiest way to do that is to copy the
+ // stop hooks and iterate over the copy.
+ StopHookCollection stop_hooks_copy = m_stop_hooks;
+ for (auto stop_entry : stop_hooks_copy) {
StopHookSP cur_hook_sp = stop_entry.second;
if (!cur_hook_sp->IsActive())
continue;
diff --git a/lldb/test/API/commands/target/stop-hooks/TestStopHookScripted.py b/lldb/test/API/commands/target/stop-hooks/TestStopHookScripted.py
index 954cac1592435..c0e3c2a8fcf31 100644
--- a/lldb/test/API/commands/target/stop-hooks/TestStopHookScripted.py
+++ b/lldb/test/API/commands/target/stop-hooks/TestStopHookScripted.py
@@ -48,6 +48,39 @@ def test_bad_handler(self):
"Got the right error",
)
+ def test_self_deleting(self):
+ """Test that we can handle a stop hook that deletes itself"""
+ self.script_setup()
+ # Run to the first breakpoint before setting the stop hook
+ # so we don't have to figure out where it showed up in the new
+ # target.
+ (target, process, thread, bkpt) = lldbutil.run_to_source_breakpoint(
+ self, "Stop here first", self.main_source_file
+ )
+
+ # Now add our stop hook and register it:
+ result = lldb.SBCommandReturnObject()
+ command = "target stop-hook add -P stop_hook.self_deleting_stop"
+ self.interp.HandleCommand(command, result)
+ self.assertCommandReturn(result, f"Added my stop hook: {result.GetError()}")
+
+ result_str = result.GetOutput()
+ p = re.compile("Stop hook #([0-9]+) added.")
+ m = p.match(result_str)
+ current_stop_hook_id = m.group(1)
+ command = "command script add -o -f stop_hook.handle_stop_hook_id handle_id"
+ self.interp.HandleCommand(command, result)
+ self.assertCommandReturn(result, "Added my command")
+
+ command = f"handle_id {current_stop_hook_id}"
+ self.interp.HandleCommand(command, result)
+ self.assertCommandReturn(result, "Registered my stop ID")
+
+ # Now step the process and make sure the stop hook was deleted.
+ thread.StepOver()
+ self.interp.HandleCommand("target stop-hook list", result)
+ self.assertEqual(result.GetOutput().rstrip(), "No stop hooks.", "Deleted hook")
+
def test_stop_hooks_scripted(self):
"""Test that a scripted stop hook works with no specifiers"""
self.stop_hooks_scripted(5, "-I false")
diff --git a/lldb/test/API/commands/target/stop-hooks/stop_hook.py b/lldb/test/API/commands/target/stop-hooks/stop_hook.py
index cb7a4337c40d4..142c4ab4c5d89 100644
--- a/lldb/test/API/commands/target/stop-hooks/stop_hook.py
+++ b/lldb/test/API/commands/target/stop-hooks/stop_hook.py
@@ -48,3 +48,27 @@ def handle_stop(self):
class no_handle_stop:
def __init__(self, target, extra_args, dict):
print("I am okay")
+
+class self_deleting_stop:
+ def __init__(self, target, extra_args, dict):
+ self.target = target
+
+ def handle_stop(self, exe_ctx, stream):
+ interp = exe_ctx.target.debugger.GetCommandInterpreter()
+ result = lldb.SBCommandReturnObject()
+ interp.HandleCommand("handle_id", result)
+ id_str = result.GetOutput().rstrip()
+
+ command = f"target stop-hook delete {id_str}"
+ interp.HandleCommand(command, result)
+
+stop_hook_id = 0
+def handle_stop_hook_id(debugger, command, exe_ctx, result, extra_args):
+ global stop_hook_id
+ if command == "":
+ result.AppendMessage(str(stop_hook_id))
+ else:
+ stop_hook_id = int(command)
+
+
+
>From 95cec34938436d5eef25c73ce71da1bdddeef387 Mon Sep 17 00:00:00 2001
From: Jim Ingham <jingham at apple.com>
Date: Tue, 23 Sep 2025 17:20:21 -0700
Subject: [PATCH 2/3] formatting
---
lldb/source/Target/Target.cpp | 2 +-
.../commands/target/stop-hooks/TestStopHookScripted.py | 4 ++--
lldb/test/API/commands/target/stop-hooks/stop_hook.py | 9 +++++----
3 files changed, 8 insertions(+), 7 deletions(-)
diff --git a/lldb/source/Target/Target.cpp b/lldb/source/Target/Target.cpp
index e94fe854f8157..baf28c6de0ec7 100644
--- a/lldb/source/Target/Target.cpp
+++ b/lldb/source/Target/Target.cpp
@@ -3171,7 +3171,7 @@ bool Target::RunStopHooks(bool at_initial_stop) {
bool should_stop = false;
bool requested_continue = false;
- // A stop hook might get deleted while running stop hooks.
+ // A stop hook might get deleted while running stop hooks.
// We have to decide what that means. We will follow the rule that deleting
// a stop hook while processing these stop hooks will delete it for FUTURE
// stops but not this stop. The easiest way to do that is to copy the
diff --git a/lldb/test/API/commands/target/stop-hooks/TestStopHookScripted.py b/lldb/test/API/commands/target/stop-hooks/TestStopHookScripted.py
index c0e3c2a8fcf31..8e91781b87a39 100644
--- a/lldb/test/API/commands/target/stop-hooks/TestStopHookScripted.py
+++ b/lldb/test/API/commands/target/stop-hooks/TestStopHookScripted.py
@@ -63,7 +63,7 @@ def test_self_deleting(self):
command = "target stop-hook add -P stop_hook.self_deleting_stop"
self.interp.HandleCommand(command, result)
self.assertCommandReturn(result, f"Added my stop hook: {result.GetError()}")
-
+
result_str = result.GetOutput()
p = re.compile("Stop hook #([0-9]+) added.")
m = p.match(result_str)
@@ -80,7 +80,7 @@ def test_self_deleting(self):
thread.StepOver()
self.interp.HandleCommand("target stop-hook list", result)
self.assertEqual(result.GetOutput().rstrip(), "No stop hooks.", "Deleted hook")
-
+
def test_stop_hooks_scripted(self):
"""Test that a scripted stop hook works with no specifiers"""
self.stop_hooks_scripted(5, "-I false")
diff --git a/lldb/test/API/commands/target/stop-hooks/stop_hook.py b/lldb/test/API/commands/target/stop-hooks/stop_hook.py
index 142c4ab4c5d89..a41190baeadf2 100644
--- a/lldb/test/API/commands/target/stop-hooks/stop_hook.py
+++ b/lldb/test/API/commands/target/stop-hooks/stop_hook.py
@@ -49,6 +49,7 @@ class no_handle_stop:
def __init__(self, target, extra_args, dict):
print("I am okay")
+
class self_deleting_stop:
def __init__(self, target, extra_args, dict):
self.target = target
@@ -58,17 +59,17 @@ def handle_stop(self, exe_ctx, stream):
result = lldb.SBCommandReturnObject()
interp.HandleCommand("handle_id", result)
id_str = result.GetOutput().rstrip()
-
+
command = f"target stop-hook delete {id_str}"
interp.HandleCommand(command, result)
+
stop_hook_id = 0
+
+
def handle_stop_hook_id(debugger, command, exe_ctx, result, extra_args):
global stop_hook_id
if command == "":
result.AppendMessage(str(stop_hook_id))
else:
stop_hook_id = int(command)
-
-
-
>From 73ac3a038abd0c451b354b93018f56ddb1038c11 Mon Sep 17 00:00:00 2001
From: Jim Ingham <jingham at apple.com>
Date: Wed, 24 Sep 2025 16:06:04 -0700
Subject: [PATCH 3/3] Document the one-stop-hook-deletes-another behavior.
---
lldb/source/Commands/CommandObjectTarget.cpp | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/lldb/source/Commands/CommandObjectTarget.cpp b/lldb/source/Commands/CommandObjectTarget.cpp
index 940be42d1b6e3..e3f169ab4fa10 100644
--- a/lldb/source/Commands/CommandObjectTarget.cpp
+++ b/lldb/source/Commands/CommandObjectTarget.cpp
@@ -5117,6 +5117,15 @@ class CommandObjectTargetStopHookDelete : public CommandObjectParsed {
: CommandObjectParsed(interpreter, "target stop-hook delete",
"Delete a stop-hook.",
"target stop-hook delete [<idx>]") {
+ SetHelpLong(
+ R"(
+Deletes the stop hook by index.
+
+At any given stop, all enabled stop hooks that pass the stop filter will
+get a chance to run. That means if one stop-hook deletes another stop hook
+while executing, the deleted stop hook will still fire for the stop at which
+it was deleted.
+ )");
AddSimpleArgumentList(eArgTypeStopHookID, eArgRepeatStar);
}
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