From mboxrd@z Thu Jan  1 00:00:00 1970
From: ynorov@caviumnetworks.com (Yury Norov)
Date: Mon, 21 Mar 2016 21:43:12 +0300
Subject: [RFC5 PATCH v6 00/21] ILP32 for ARM64
In-Reply-To: <56EFD9B0.6080004@huawei.com>
References: <56AC38F1.2030608@huawei.com> <20160218223506.GA7816@yury-N73SV>
 <mvm8u29ukqw.fsf@hawking.suse.de>
 <20160225202855.GD16123@yury-N73SV> <56EBD84D.2060009@huawei.com>
 <20160318154918.GA1595@yury-N73SV> <56EC24EE.6020803@suse.de>
 <20160318164627.GA3201@yury-N73SV> <56EE5B6E.6030305@huawei.com>
 <56EFD9B0.6080004@huawei.com>
Message-ID: <20160321184312.GB26563@yury-N73SV>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Mon, Mar 21, 2016 at 07:23:28PM +0800, Zhangjian (Bamvor) wrote:
> >>So this most probably means that ilp32 code doesn't handle one of cloned
> >>item properly. I have already discovered a bug where child processes
> >>used parent TLS,
> >It is a kernel bug or glibc bug? Could you please explain it or show the patch?
> >The current ILP32 patches looks good to me. Recently, I backport these patches
> >to our 4.1 kernel. And I saw crash frequently even if I only do a single print
> >or infinite loop. There is some small changes about tls register after 4.1. I
> >am not sure if it is a similar issue. It is great if you have some suggestions/
> >ideas.
> My issue is because I forget to change is_compat_task to
> is_a32_compat_task in arch/arm64/kernel/process.c such piece of code
> is delete after commit d00a3810c162 ("arm64: context-switch user tls
> register tpidr_el0 for compat tasks). It is not exist in upstream
> kernel, never mind.
> 
> Meanwhile, I found that it seem that there is another is_compat_task
> in tls_thread_flush. Is it relative the issue you mentioned?
> 
> ```
> diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
> index 432b094..9ab968c 100644
> --- a/arch/arm64/kernel/process.c
> +++ b/arch/arm64/kernel/process.c
> @@ -209,7 +209,7 @@ static void tls_thread_flush(void)
>  {
>         asm ("msr tpidr_el0, xzr");
> 
> -       if (is_compat_task()) {
> +       if (is_a32_compat_task()) {
>                 current->thread.tp_value = 0;
> 
>                 /*
> ```
> 
> Regards
> 
> Bamvor

Hi,

This fix looks correct, though doesn't fix issue.
Thank you.

Yury.