linux-kernel - Re: RCU tests for Maple Tree

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20210517163048.7zcg2435lsvg25ef@revolver>
Date:   Mon, 17 May 2021 16:30:53 +0000
From:   Liam Howlett <liam.howlett@...cle.com>
To:     "Paul E. McKenney" <paulmck@...nel.org>
CC:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>
Subject: Re: RCU tests for Maple Tree

* Paul E. McKenney <paulmck@...nel.org> [210517 11:40]:
> Hello, Liam!
> 
> Apologies for my being so slow here, but just wanted to double-check my
> understanding of this code.
> 
> There appear to be two tests that execute from run_check_rcu():
> 
> o	rcu_loop().  This appears to have RCU readers scanning the tree
> 	while an updater is adding a single range.  (Or replacing it,
> 	as the case might be.)
> 
> o	rcu_val().  This appears to have RCU readers repeatedly reading a
> 	given value while an updater is adding/replacing a single range.
> 	The test complains if no one sees the new value.
> 
> These tests appear to be the only use of threads, though perhaps the
> test harness has some way of creating threads that I missed.
> 
> Are there other tests that I should be looking for?

No, those are the only ones I'm running with threads right now.  I think
all RCU tests are run from check_rcu() iirc.  This did yield results of
failures that had to be addressed so I'm somewhat confident that it's
actually working.

>From your wording I'm gathering I need to increase this by a lot more
test cases?

Thanks,
Liam