Re: [PATCH] blk-mq: Clear out elevator private data

2018-04-18 Thread Paolo Valente
> Il giorno 17 apr 2018, alle ore 23:42, Kees Cook ha > scritto: > > Some elevators may not correctly check rq->rq_flags & RQF_ELVPRIV, and > may attempt to read rq->elv fields. When requests got reused, this > caused BFQ to think it already had a bfqq (rq->elv.priv[1]) allocated. Hi Kees, wh

Re: [PATCH] blk-mq: Clear out elevator private data

2018-04-17 Thread Jens Axboe
On 4/17/18 4:57 PM, Kees Cook wrote: > On Tue, Apr 17, 2018 at 2:45 PM, Jens Axboe wrote: >> On 4/17/18 3:42 PM, Kees Cook wrote: >>> Some elevators may not correctly check rq->rq_flags & RQF_ELVPRIV, and >>> may attempt to read rq->elv fields. When requests got reused, this >>> caused BFQ to thin

Re: [PATCH] blk-mq: Clear out elevator private data

2018-04-17 Thread Kees Cook
On Tue, Apr 17, 2018 at 2:45 PM, Jens Axboe wrote: > On 4/17/18 3:42 PM, Kees Cook wrote: >> Some elevators may not correctly check rq->rq_flags & RQF_ELVPRIV, and >> may attempt to read rq->elv fields. When requests got reused, this >> caused BFQ to think it already had a bfqq (rq->elv.priv[1]) a

Re: [PATCH] blk-mq: Clear out elevator private data

2018-04-17 Thread Jens Axboe
On 4/17/18 3:42 PM, Kees Cook wrote: > Some elevators may not correctly check rq->rq_flags & RQF_ELVPRIV, and > may attempt to read rq->elv fields. When requests got reused, this > caused BFQ to think it already had a bfqq (rq->elv.priv[1]) allocated. > This could lead to odd behaviors like having

[PATCH] blk-mq: Clear out elevator private data

2018-04-17 Thread Kees Cook
Some elevators may not correctly check rq->rq_flags & RQF_ELVPRIV, and may attempt to read rq->elv fields. When requests got reused, this caused BFQ to think it already had a bfqq (rq->elv.priv[1]) allocated. This could lead to odd behaviors like having the sense buffer address slowly start increme