linux-kernel - Re: [RFC][PATCH 3/3] Do not use rqhash when merges disabled

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: Windows password security audit tool. GUI, reports in PDF.

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

Date:	Wed, 23 Apr 2008 20:59:30 -0400
From:	"Alan D. Brunelle" <Alan.Brunelle@...com>
To:	Aaron Carroll <aaronc@...ato.unsw.edu.au>
Cc:	linux-kernel@...r.kernel.org, Jens Axboe <jens.axboe@...cle.com>
Subject: Re: [RFC][PATCH 3/3] Do not use rqhash when merges disabled

Aaron Carroll wrote:
> Hi Alan,
> 
> Alan D. Brunelle wrote:
>> --- a/block/elevator.c
>> +++ b/block/elevator.c
>> @@ -313,7 +313,7 @@ static inline void __elv_rqhash_del(struct request
>> *rq)
>>  
>>  static void elv_rqhash_del(struct request_queue *q, struct request *rq)
>>  {
>> -    if (ELV_ON_HASH(rq))
>> +    if (!blk_queue_nomerges(q) && ELV_ON_HASH(rq))
>>          __elv_rqhash_del(rq);
>>  }
> 
> If you switch the nomerges tunable while requests are in flight, it is
> possible that
> a request is put into the rqhash table but not removed here, leading to
> the BUG_ON
> in elv_dequeue_request() triggering.  ELV_ON_HASH needs to be checked
> regardless of
> the nomerges state.
> 
> 
> -- Aaron
> 
> 

Hi Aaron -

Good catch - that was a last minute addition, the ELV_ON_HASH should be
sufficient without the check for blk_queue_nomerges, right?

Alan
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/