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Re: [Qemu-devel] [PATCH v1 2/2] gdbstub: don't fail on vCont; C04:0; c p
From: |
Alex Bennée |
Subject: |
Re: [Qemu-devel] [PATCH v1 2/2] gdbstub: don't fail on vCont; C04:0; c packets |
Date: |
Wed, 31 May 2017 19:16:05 +0100 |
User-agent: |
mu4e 0.9.19; emacs 25.2.50.2 |
Claudio Imbrenda <address@hidden> writes:
> On Wed, 31 May 2017 19:06:29 +0200
> Greg Kurz <address@hidden> wrote:
>
>> On Wed, 31 May 2017 18:51:06 +0200
>> Claudio Imbrenda <address@hidden> wrote:
>> [...]
>> > > >
>> > > > This is strange. cpu_index() is defined as:
>> > > >
>> > > > static inline int cpu_index(CPUState *cpu)
>> > > > {
>> > > > #if defined(CONFIG_USER_ONLY)
>> > > > return cpu->host_tid;
>> > > > #else
>> > > > return cpu->cpu_index + 1;
>> > > > #endif
>> > > > }
>> > > >
>> > > > therefore it shouldn't return 0 under any circumstance,
>> > > > and
>> > >
>> > > I think it is 0 for first_cpu in user mode.
>> >
>> > in linux-user/syscall.c:
>> >
>> > info->tid = gettid();
>> > cpu->host_tid = info->tid;
>> >
>> > kernel thread-ids are system-wide unique and can't be 0
>> >
>>
>> This is correct but these lines are in clone_func(). This gets called
>> for all threads but the "main" thread which I believe to be
>> associated to first_cpu.
>
> then IMHO that is a bug and it needs to be corrected. the host_tid
> should be, well, the host tid, and not 0, which is never a valid
> tid for Linux.
>
> the current behaviour is simply the easiest for the "any CPU" case.
> Picking the last CPU or a random one would still be correct, and in
> that case there would be no way to explicitly address the first CPU.
OK I'll include a fix in the next iteration.
--
Alex Bennée
- [Qemu-devel] [PATCH v1 0/2] some gdbstub fixes for debug and vcont, Alex Bennée, 2017/05/31
- [Qemu-devel] [PATCH v1 2/2] gdbstub: don't fail on vCont; C04:0; c packets, Alex Bennée, 2017/05/31
- Re: [Qemu-devel] [PATCH v1 2/2] gdbstub: don't fail on vCont; C04:0; c packets, Greg Kurz, 2017/05/31
- Re: [Qemu-devel] [PATCH v1 2/2] gdbstub: don't fail on vCont; C04:0; c packets, Claudio Imbrenda, 2017/05/31
- Re: [Qemu-devel] [PATCH v1 2/2] gdbstub: don't fail on vCont; C04:0; c packets, Alex Bennée, 2017/05/31
- Re: [Qemu-devel] [PATCH v1 2/2] gdbstub: don't fail on vCont; C04:0; c packets, Greg Kurz, 2017/05/31
- Re: [Qemu-devel] [PATCH v1 2/2] gdbstub: don't fail on vCont; C04:0; c packets, Claudio Imbrenda, 2017/05/31
- Re: [Qemu-devel] [PATCH v1 2/2] gdbstub: don't fail on vCont; C04:0; c packets, Greg Kurz, 2017/05/31
- Re: [Qemu-devel] [PATCH v1 2/2] gdbstub: don't fail on vCont; C04:0; c packets, Claudio Imbrenda, 2017/05/31
- Re: [Qemu-devel] [PATCH v1 2/2] gdbstub: don't fail on vCont; C04:0; c packets,
Alex Bennée <=
- Re: [Qemu-devel] [PATCH v1 2/2] gdbstub: don't fail on vCont; C04:0; c packets, Greg Kurz, 2017/05/31
- Re: [Qemu-devel] [PATCH v1 2/2] gdbstub: don't fail on vCont; C04:0; c packets, Alex Bennée, 2017/05/31
[Qemu-devel] [PATCH v1 1/2] gdbstub: modernise DEBUG_GDB, Alex Bennée, 2017/05/31