| Message ID | 1411031071-40390-2-git-send-email-dahi@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 09/18/2014 11:04 AM, David Hildenbrand wrote: > This patch should fix the bug reported in https://lkml.org/lkml/2014/9/11/249. > > We have to initialize at least the atomic_flags and the cmd_flags when > allocating storage for the requests. > > Otherwise blk_mq_timeout_check() might dereference uninitialized pointers when > racing with the creation of a request. > > Also move the reset of cmd_flags for the initializing code to the point where a > request is freed. So we will never end up with pending flush request indicators > that might trigger dereferences of invalid pointers in blk_mq_timeout_check(). > > Cc: stable@vger.kernel.org > Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> So far our testers were not able to reproduce the problem with this patch applied, we will continue testing over weekend. I will give an ACK/NACK on monday then. Thanks > --- > block/blk-mq.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/block/blk-mq.c b/block/blk-mq.c > index 383ea0c..eed6340 100644 > --- a/block/blk-mq.c > +++ b/block/blk-mq.c > @@ -203,7 +203,6 @@ __blk_mq_alloc_request(struct blk_mq_alloc_data *data, int rw) > if (tag != BLK_MQ_TAG_FAIL) { > rq = data->hctx->tags->rqs[tag]; > > - rq->cmd_flags = 0; > if (blk_mq_tag_busy(data->hctx)) { > rq->cmd_flags = REQ_MQ_INFLIGHT; > atomic_inc(&data->hctx->nr_active); > @@ -258,6 +257,7 @@ static void __blk_mq_free_request(struct blk_mq_hw_ctx *hctx, > > if (rq->cmd_flags & REQ_MQ_INFLIGHT) > atomic_dec(&hctx->nr_active); > + rq->cmd_flags = 0; > > clear_bit(REQ_ATOM_STARTED, &rq->atomic_flags); > blk_mq_put_tag(hctx, tag, &ctx->last_tag); > @@ -1404,6 +1404,8 @@ static struct blk_mq_tags *blk_mq_init_rq_map(struct blk_mq_tag_set *set, > left -= to_do * rq_size; > for (j = 0; j < to_do; j++) { > tags->rqs[i] = p; > + tags->rqs[i]->atomic_flags = 0; > + tags->rqs[i]->cmd_flags = 0; > if (set->ops->init_request) { > if (set->ops->init_request(set->driver_data, > tags->rqs[i], hctx_idx, i, > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 09/18/2014 11:04 AM, David Hildenbrand wrote: > This patch should fix the bug reported in https://lkml.org/lkml/2014/9/11/249. > > We have to initialize at least the atomic_flags and the cmd_flags when > allocating storage for the requests. > > Otherwise blk_mq_timeout_check() might dereference uninitialized pointers when > racing with the creation of a request. > > Also move the reset of cmd_flags for the initializing code to the point where a > request is freed. So we will never end up with pending flush request indicators > that might trigger dereferences of invalid pointers in blk_mq_timeout_check(). > > Cc: stable@vger.kernel.org > Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Can you please add Reported-by: Paulo De Rezende Pinatti <ppinatti@linux.vnet.ibm.com> Tested-by: Paulo De Rezende Pinatti <ppinatti@linux.vnet.ibm.com> as Paulo did the testing work? We thing this patch is fine and should go upstream. Christian > --- > block/blk-mq.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/block/blk-mq.c b/block/blk-mq.c > index 383ea0c..eed6340 100644 > --- a/block/blk-mq.c > +++ b/block/blk-mq.c > @@ -203,7 +203,6 @@ __blk_mq_alloc_request(struct blk_mq_alloc_data *data, int rw) > if (tag != BLK_MQ_TAG_FAIL) { > rq = data->hctx->tags->rqs[tag]; > > - rq->cmd_flags = 0; > if (blk_mq_tag_busy(data->hctx)) { > rq->cmd_flags = REQ_MQ_INFLIGHT; > atomic_inc(&data->hctx->nr_active); > @@ -258,6 +257,7 @@ static void __blk_mq_free_request(struct blk_mq_hw_ctx *hctx, > > if (rq->cmd_flags & REQ_MQ_INFLIGHT) > atomic_dec(&hctx->nr_active); > + rq->cmd_flags = 0; > > clear_bit(REQ_ATOM_STARTED, &rq->atomic_flags); > blk_mq_put_tag(hctx, tag, &ctx->last_tag); > @@ -1404,6 +1404,8 @@ static struct blk_mq_tags *blk_mq_init_rq_map(struct blk_mq_tag_set *set, > left -= to_do * rq_size; > for (j = 0; j < to_do; j++) { > tags->rqs[i] = p; > + tags->rqs[i]->atomic_flags = 0; > + tags->rqs[i]->cmd_flags = 0; > if (set->ops->init_request) { > if (set->ops->init_request(set->driver_data, > tags->rqs[i], hctx_idx, i, > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 2014-09-22 08:15, Christian Borntraeger wrote: > On 09/18/2014 11:04 AM, David Hildenbrand wrote: >> This patch should fix the bug reported in https://lkml.org/lkml/2014/9/11/249. >> >> We have to initialize at least the atomic_flags and the cmd_flags when >> allocating storage for the requests. >> >> Otherwise blk_mq_timeout_check() might dereference uninitialized pointers when >> racing with the creation of a request. >> >> Also move the reset of cmd_flags for the initializing code to the point where a >> request is freed. So we will never end up with pending flush request indicators >> that might trigger dereferences of invalid pointers in blk_mq_timeout_check(). >> >> Cc: stable@vger.kernel.org >> Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> > > Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> > > Can you please add > Reported-by: Paulo De Rezende Pinatti <ppinatti@linux.vnet.ibm.com> > Tested-by: Paulo De Rezende Pinatti <ppinatti@linux.vnet.ibm.com> > > as Paulo did the testing work? > > We thing this patch is fine and should go upstream. I might have to pick'n rebase the series, in which case I'll add it. But I already queued it up last week, so if I don't, then I can't easily add it. I wish the git notes wasn't such a horrible and unusable hack, so we had a chance to annotate commits without having to rewrite history...
diff --git a/block/blk-mq.c b/block/blk-mq.c index 383ea0c..eed6340 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -203,7 +203,6 @@ __blk_mq_alloc_request(struct blk_mq_alloc_data *data, int rw) if (tag != BLK_MQ_TAG_FAIL) { rq = data->hctx->tags->rqs[tag]; - rq->cmd_flags = 0; if (blk_mq_tag_busy(data->hctx)) { rq->cmd_flags = REQ_MQ_INFLIGHT; atomic_inc(&data->hctx->nr_active); @@ -258,6 +257,7 @@ static void __blk_mq_free_request(struct blk_mq_hw_ctx *hctx, if (rq->cmd_flags & REQ_MQ_INFLIGHT) atomic_dec(&hctx->nr_active); + rq->cmd_flags = 0; clear_bit(REQ_ATOM_STARTED, &rq->atomic_flags); blk_mq_put_tag(hctx, tag, &ctx->last_tag); @@ -1404,6 +1404,8 @@ static struct blk_mq_tags *blk_mq_init_rq_map(struct blk_mq_tag_set *set, left -= to_do * rq_size; for (j = 0; j < to_do; j++) { tags->rqs[i] = p; + tags->rqs[i]->atomic_flags = 0; + tags->rqs[i]->cmd_flags = 0; if (set->ops->init_request) { if (set->ops->init_request(set->driver_data, tags->rqs[i], hctx_idx, i,
This patch should fix the bug reported in https://lkml.org/lkml/2014/9/11/249. We have to initialize at least the atomic_flags and the cmd_flags when allocating storage for the requests. Otherwise blk_mq_timeout_check() might dereference uninitialized pointers when racing with the creation of a request. Also move the reset of cmd_flags for the initializing code to the point where a request is freed. So we will never end up with pending flush request indicators that might trigger dereferences of invalid pointers in blk_mq_timeout_check(). Cc: stable@vger.kernel.org Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> --- block/blk-mq.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)