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Date: Fri, 16 Sep 2016 14:57:54 +0200
From: Ingo Molnar <mingo@kernel.org>
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: tip-bot for Andy Lutomirski <tipbot@zytor.com>,
        linux-tip-commits@vger.kernel.org, luto@kernel.org, hpa@zytor.com,
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Subject: Re: [tip:x86/asm] x86/dumpstack: Pin the target stack when dumping it
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* Josh Poimboeuf <jpoimboe@redhat.com> wrote:

> On Fri, Sep 16, 2016 at 06:55:57AM -0500, Josh Poimboeuf wrote:
> > On Fri, Sep 16, 2016 at 02:17:46AM -0700, tip-bot for Andy Lutomirski wrote:
> > > Commit-ID:  1959a60182f48879635812a03a99c02231ea8677
> > > Gitweb:     http://git.kernel.org/tip/1959a60182f48879635812a03a99c02231ea8677
> > > Author:     Andy Lutomirski <luto@kernel.org>
> > > AuthorDate: Thu, 15 Sep 2016 22:45:45 -0700
> > > Committer:  Ingo Molnar <mingo@kernel.org>
> > > CommitDate: Fri, 16 Sep 2016 09:18:53 +0200
> > > 
> > > x86/dumpstack: Pin the target stack when dumping it
> > > 
> > > Specifically, pin the stack in save_stack_trace_tsk() and
> > > show_trace_log_lvl().
> > > 
> > > This will prevent a crash if the target task dies before or while
> > > dumping its stack once we start freeing task stacks early.
> > 
> > This causes a hang:
> 
> The problem is that show_stack_log_lvl() can be called with a NULL
> task_struct pointer to indicate 'current'.

Could you please send a quick fix that addresses the hang by turning the NULL into 
'current' or so?

> No idea why that convention exists -- IMO we should just require the
> caller to pass 'current' directly.

For hysterical raisins I believe. It appears just a single caller passes 
non-current. Feel free to change this.

Thanks,

	Ingo