Re: [PATCH] lockdep: Show up to three levels for a deadlock scenario

From: Dhaval Giani
Date: Tue Dec 19 2017 - 11:54:49 EST


On 2017-12-19 11:52 AM, Steven Rostedt wrote:
> On Tue, 19 Dec 2017 17:46:19 +0100
> Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>
>
>> It really isn't that hard, Its mostly a question of TL;DR.
>>
>> #0 is useless and should be thrown out
>> #1 shows where we take #1 while holding #0
>> ..
>> #n shows where we take #n while holding #n-1
>>
>> And the bottom callstack shows where we take #0 while holding #n. Which
>> gets you a nice circle in your graph, which spells deadlock.
>>
>> Plenty people have shown they get this stuff.
>
>
> Then I suggest that you can either take my patch to improve the
> visual or remove the visual completely, as nobody cares about it.
>

I prefer the former. As Steven has mentioned elsewhere, people find
lockdep output hard to follow (enough that he has given talks :) )

Dhaval