Re: [PATCH v4 05/15] lockdep: Make check_prev_add can use a separate stack_trace

From	Byungchul Park <byungchul.park@lge.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH v4 05/15] lockdep: Make check_prev_add can use a separate stack_trace
Date	2017-01-13 03:50 +0100
Message-ID	<sZ06d-3zV-1@gated-at.bofh.it> (permalink)
References	<sMlLb-7BJ-3@gated-at.bofh.it> <sMlLc-7BJ-27@gated-at.bofh.it> <sYQgy-66R-13@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Thu, Jan 12, 2017 at 05:16:43PM +0100, Peter Zijlstra wrote:
> On Fri, Dec 09, 2016 at 02:12:01PM +0900, Byungchul Park wrote:
> > check_prev_add() saves a stack trace of the current. But crossrelease
> > feature needs to use a separate stack trace of another context in
> > check_prev_add(). So make it use a separate stack trace instead of one
> > of the current.
> > 
> 
> So I was thinking, can't we make check_prevs_add() create the stack
> trace unconditionally but record if we used it or not, and then return
> the entries when unused. All that is serialized by graph_lock anyway and
> that way we already pass a stack into check_prev_add() so we can easily
> pass in a different one.
> 
> I think that removes a bunch of tricky and avoids all the new tricky.

Looks very good.

Thread

Re: [PATCH v4 05/15] lockdep: Make check_prev_add can use a separate  stack_trace Peter Zijlstra <peterz@infradead.org> - 2017-01-12 17:20 +0100
  Re: [PATCH v4 05/15] lockdep: Make check_prev_add can use a separate  stack_trace Byungchul Park <byungchul.park@lge.com> - 2017-01-13 03:50 +0100
  [PATCH] lockdep: Make a stack_trace instance passed to check_prev_add as an arg Byungchul Park <byungchul.park@lge.com> - 2017-01-13 05:10 +0100
    Re: [PATCH] lockdep: Make a stack_trace instance passed to  check_prev_add as an arg Byungchul Park <byungchul.park@lge.com> - 2017-01-13 05:40 +0100
  Re: [PATCH v4 05/15] lockdep: Make check_prev_add can use a separate  stack_trace Byungchul Park <byungchul.park@lge.com> - 2017-01-13 11:20 +0100
    [PATCH 2/2] lockdep: Pass a callback arg to check_prev_add() to handle stack_trace Byungchul Park <byungchul.park@lge.com> - 2017-01-13 11:20 +0100

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