| Message ID | 1472500919-14631-3-git-send-email-eric.desrochers@canonical.com |
|---|---|
| State | New |
| Headers | show |
On Mon, Aug 29, 2016 at 04:01:59PM -0400, Eric Desrochers wrote: > From: Thomas Gleixner <tglx@linutronix.de> > > BugLink: https://bugs.launchpad.net/bugs/1572630 > > queue_for_each_ctx() iterates over per_cpu variables under the assumption that > the possible cpu mask cannot have holes. That's wrong as all cpumasks can have > holes. In case there are holes the iteration ends up accessing uninitialized > memory and crashing as a result. > > Replace the macro by a proper for_each_possible_cpu() loop and drop the unused > macro blk_ctx_sum() which references queue_for_each_ctx(). > > Reported-by: Xiong Zhou <jencce.kernel@gmail.com> > Signed-off-by: Thomas Gleixner <tglx@linutronix.de> > Signed-off-by: Jens Axboe <axboe@fb.com> > (cherry picked from commit 897bb0c7f1ea82d7cc882b19790b5e1df00ffc29) > Signed-off-by: Eric Desrochers <eric.desrochers@canonical.com> > --- > block/blk-mq-sysfs.c | 5 ++++- > block/blk-mq.c | 3 ++- > include/linux/blk-mq.h | 14 -------------- > 3 files changed, 6 insertions(+), 16 deletions(-) > > diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c > index 1cf1878..8d41163 100644 > --- a/block/blk-mq-sysfs.c > +++ b/block/blk-mq-sysfs.c > @@ -413,14 +413,17 @@ static void blk_mq_sysfs_init(struct request_queue *q) > struct blk_mq_hw_ctx *hctx; > struct blk_mq_ctx *ctx; > int i; > + int cpu; > This is technically a 'backport' since it isn't a clean cherry-pick. I see in the upstream patch that i was removed as we no longer have the queue_for_each_hw_ctx loop. --chris > kobject_init(&q->mq_kobj, &blk_mq_ktype); > > queue_for_each_hw_ctx(q, hctx, i) > kobject_init(&hctx->kobj, &blk_mq_hw_ktype); > > - queue_for_each_ctx(q, ctx, i) > + for_each_possible_cpu(cpu) { > + ctx = per_cpu_ptr(q->queue_ctx, cpu); > kobject_init(&ctx->kobj, &blk_mq_ctx_ktype); > + } > } > > int blk_mq_register_disk(struct gendisk *disk) > diff --git a/block/blk-mq.c b/block/blk-mq.c > index 32598d2..92b7800 100644 > --- a/block/blk-mq.c > +++ b/block/blk-mq.c > @@ -1822,11 +1822,12 @@ static void blk_mq_map_swqueue(struct request_queue *q, > /* > * Map software to hardware queues > */ > - queue_for_each_ctx(q, ctx, i) { > + for_each_possible_cpu(i) { > /* If the cpu isn't online, the cpu is mapped to first hctx */ > if (!cpumask_test_cpu(i, online_mask)) > continue; > > + ctx = per_cpu_ptr(q->queue_ctx, i); > hctx = q->mq_ops->map_queue(q, i); > cpumask_set_cpu(i, hctx->cpumask); > ctx->index_hw = hctx->nr_ctx; > diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h > index 7fc9296..a8756cd 100644 > --- a/include/linux/blk-mq.h > +++ b/include/linux/blk-mq.h > @@ -261,22 +261,8 @@ static inline void *blk_mq_rq_to_pdu(struct request *rq) > for ((i) = 0; (i) < (q)->nr_hw_queues && \ > ({ hctx = (q)->queue_hw_ctx[i]; 1; }); (i)++) > > -#define queue_for_each_ctx(q, ctx, i) \ > - for ((i) = 0; (i) < (q)->nr_queues && \ > - ({ ctx = per_cpu_ptr((q)->queue_ctx, (i)); 1; }); (i)++) > - > #define hctx_for_each_ctx(hctx, ctx, i) \ > for ((i) = 0; (i) < (hctx)->nr_ctx && \ > ({ ctx = (hctx)->ctxs[(i)]; 1; }); (i)++) > > -#define blk_ctx_sum(q, sum) \ > -({ \ > - struct blk_mq_ctx *__x; \ > - unsigned int __ret = 0, __i; \ > - \ > - queue_for_each_ctx((q), __x, __i) \ > - __ret += sum; \ > - __ret; \ > -}) > - > #endif > -- > 2.7.4 > > > -- > kernel-team mailing list > kernel-team@lists.ubuntu.com > https://lists.ubuntu.com/mailman/listinfo/kernel-team
diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c index 1cf1878..8d41163 100644 --- a/block/blk-mq-sysfs.c +++ b/block/blk-mq-sysfs.c @@ -413,14 +413,17 @@ static void blk_mq_sysfs_init(struct request_queue *q) struct blk_mq_hw_ctx *hctx; struct blk_mq_ctx *ctx; int i; + int cpu; kobject_init(&q->mq_kobj, &blk_mq_ktype); queue_for_each_hw_ctx(q, hctx, i) kobject_init(&hctx->kobj, &blk_mq_hw_ktype); - queue_for_each_ctx(q, ctx, i) + for_each_possible_cpu(cpu) { + ctx = per_cpu_ptr(q->queue_ctx, cpu); kobject_init(&ctx->kobj, &blk_mq_ctx_ktype); + } } int blk_mq_register_disk(struct gendisk *disk) diff --git a/block/blk-mq.c b/block/blk-mq.c index 32598d2..92b7800 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1822,11 +1822,12 @@ static void blk_mq_map_swqueue(struct request_queue *q, /* * Map software to hardware queues */ - queue_for_each_ctx(q, ctx, i) { + for_each_possible_cpu(i) { /* If the cpu isn't online, the cpu is mapped to first hctx */ if (!cpumask_test_cpu(i, online_mask)) continue; + ctx = per_cpu_ptr(q->queue_ctx, i); hctx = q->mq_ops->map_queue(q, i); cpumask_set_cpu(i, hctx->cpumask); ctx->index_hw = hctx->nr_ctx; diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h index 7fc9296..a8756cd 100644 --- a/include/linux/blk-mq.h +++ b/include/linux/blk-mq.h @@ -261,22 +261,8 @@ static inline void *blk_mq_rq_to_pdu(struct request *rq) for ((i) = 0; (i) < (q)->nr_hw_queues && \ ({ hctx = (q)->queue_hw_ctx[i]; 1; }); (i)++) -#define queue_for_each_ctx(q, ctx, i) \ - for ((i) = 0; (i) < (q)->nr_queues && \ - ({ ctx = per_cpu_ptr((q)->queue_ctx, (i)); 1; }); (i)++) - #define hctx_for_each_ctx(hctx, ctx, i) \ for ((i) = 0; (i) < (hctx)->nr_ctx && \ ({ ctx = (hctx)->ctxs[(i)]; 1; }); (i)++) -#define blk_ctx_sum(q, sum) \ -({ \ - struct blk_mq_ctx *__x; \ - unsigned int __ret = 0, __i; \ - \ - queue_for_each_ctx((q), __x, __i) \ - __ret += sum; \ - __ret; \ -}) - #endif