38b252aa45
This PR fixes another race condition in https://github.com/llvm/llvm-project/pull/90930. The failure was found by @labath with this log: https://paste.debian.net/hidden/30235a5c/: ``` dotest_wrapper. < 15> send packet: $z0,224505,1#65 ... b-remote.async> < 22> send packet: $vCont;s:p1dcf.1dcf#4c intern-state GDBRemoteClientBase::Lock::Lock sent packet: \x03 b-remote.async> < 818> read packet: $T13thread:p1dcf.1dcf;name:a.out;threads:1dcf,1dd2;jstopinfo:5b7b226e616d65223a22612e6f7574222c22726561736f6e223a227369676e616c222c227369676e616c223a31392c22746964223a373633317d2c7b226e616d65223a22612e6f7574222c22746964223a373633347d5d;thread-pcs:0000000000224505,00007f4e4302119a;00:0000000000000000;01:0000000000000000;02:0100000000000000;03:0000000000000000;04:9084997dfc7f0000;05:a8742a0000000000;06:b084997dfc7f0000;07:6084997dfc7f0000;08:0000000000000000;09:00d7e5424e7f0000;0a:d0d9e5424e7f0000;0b:0202000000000000;0c:80cc290000000000;0d:d8cc1c434e7f0000;0e:2886997dfc7f0000;0f:0100000000000000;10:0545220000000000;11:0602000000000000;12:3300000000000000;13:0000000000000000;14:0000000000000000;15:2b00000000000000;16:80fbe5424e7f0000;17:0000000000000000;18:0000000000000000;19:0000000000000000;reason:signal;#b9 ``` It shows an async interrupt "\x03" was sent immediately after `vCont;s` single step over breakpoint at address `0x224505` (which was disabled before vCont). And the later stop was still at the original PC (0x224505) not moving forward. The investigation shows the failure happens when timeout is short and async interrupt is sent to lldb-server immediately after vCont so ptrace() resumes and then async interrupts debuggee immediately so debuggee does not get a chance to execute and move PC. So it enters stop mode immediately at original PC. `ThreadPlanStepOverBreakpoint` does not expect PC not moving and reports stop at the original place. To fix this, the PR prevents `ThreadPlanSingleThreadTimeout` from being created during `ThreadPlanStepOverBreakpoint` by introduces a new `SupportsResumeOthers()` method and `ThreadPlanStepOverBreakpoint` returns false for it. This makes sense because we should never resume threads during step over breakpoint anyway otherwise it might cause other threads to miss breakpoint. --------- Co-authored-by: jeffreytan81 <jeffreytan@fb.com>
59 lines
1.9 KiB
C++
59 lines
1.9 KiB
C++
//===-- ThreadPlanStepOverBreakpoint.h --------------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLDB_TARGET_THREADPLANSTEPOVERBREAKPOINT_H
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#define LLDB_TARGET_THREADPLANSTEPOVERBREAKPOINT_H
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#include "lldb/Target/Thread.h"
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#include "lldb/Target/ThreadPlan.h"
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namespace lldb_private {
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class ThreadPlanStepOverBreakpoint : public ThreadPlan {
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public:
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ThreadPlanStepOverBreakpoint(Thread &thread);
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~ThreadPlanStepOverBreakpoint() override;
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void GetDescription(Stream *s, lldb::DescriptionLevel level) override;
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bool ValidatePlan(Stream *error) override;
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bool ShouldStop(Event *event_ptr) override;
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bool SupportsResumeOthers() override;
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bool StopOthers() override;
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lldb::StateType GetPlanRunState() override;
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bool WillStop() override;
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void DidPop() override;
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bool MischiefManaged() override;
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void ThreadDestroyed() override;
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void SetAutoContinue(bool do_it);
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bool ShouldAutoContinue(Event *event_ptr) override;
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bool IsPlanStale() override;
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lldb::addr_t GetBreakpointLoadAddress() const { return m_breakpoint_addr; }
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protected:
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bool DoPlanExplainsStop(Event *event_ptr) override;
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bool DoWillResume(lldb::StateType resume_state, bool current_plan) override;
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void ReenableBreakpointSite();
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private:
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lldb::addr_t m_breakpoint_addr;
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lldb::user_id_t m_breakpoint_site_id;
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bool m_auto_continue;
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bool m_reenabled_breakpoint_site;
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ThreadPlanStepOverBreakpoint(const ThreadPlanStepOverBreakpoint &) = delete;
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const ThreadPlanStepOverBreakpoint &
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operator=(const ThreadPlanStepOverBreakpoint &) = delete;
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};
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} // namespace lldb_private
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#endif // LLDB_TARGET_THREADPLANSTEPOVERBREAKPOINT_H
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