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Re: [PATCH 4/5] Fix deadlock in _int_free consistency check

From: Andreas Schwab <schwab at suse dot de>
To: Florian Weimer <fweimer at redhat dot com>
Cc: Wilco Dijkstra <Wilco dot Dijkstra at arm dot com>, "libc-alpha\@sourceware.org" <libc-alpha at sourceware dot org>, nd <nd at arm dot com>
Date: Thu, 12 Oct 2017 12:16:44 +0200
Subject: Re: [PATCH 4/5] Fix deadlock in _int_free consistency check
Authentication-results: sourceware.org; auth=none
References: <DB6PR0801MB20537B594B5629491605CD74834B0@DB6PR0801MB2053.eurprd08.prod.outlook.com> <bcdc56b5-b872-b81e-2e71-f9d6be260fff@redhat.com>

On Okt 12 2017, Florian Weimer <fweimer@redhat.com> wrote:

> On 10/12/2017 11:35 AM, Wilco Dijkstra wrote:
>> This patch fixes a deadlock in the fastbin consistency check.
>> If we fail the fast check due to concurrent modifications to
>> the next chunk or system_mem, we should not lock if we already
>> have the arena lock.  Simplify the check to make it obviously
>> correct.
>
> I don't think the subject line is correct.  What is the deadlock?  I don't
> see it.

The problem is that commit 24cffce736 inverted the condition on
have_lock, which is wrong.

Andreas.

-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
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"And now for something completely different."

Follow-Ups:
- Re: [PATCH 4/5] Fix deadlock in _int_free consistency check
  - From: Florian Weimer

References:
- [PATCH 4/5] Fix deadlock in _int_free consistency check
  - From: Wilco Dijkstra
- Re: [PATCH 4/5] Fix deadlock in _int_free consistency check
  - From: Florian Weimer

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