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authorThomas Gleixner <tglx@linutronix.de>2016-03-19 11:30:33 +0100
committerJens Axboe <axboe@fb.com>2016-03-20 09:34:02 -0600
commit897bb0c7f1ea82d7cc882b19790b5e1df00ffc29 (patch)
tree97b9ef1ba99b9c0f76ca57e398a55fa124ec3f7e /block
parent5173cb814b36439a9d9537016965e75798b9f130 (diff)
downloadlinux-sh-897bb0c7f1ea82d7cc882b19790b5e1df00ffc29.tar.gz
blk-mq: Use proper cpumask iterator
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>
Diffstat (limited to 'block')
-rw-r--r--block/blk-mq-sysfs.c6
-rw-r--r--block/blk-mq.c3
2 files changed, 6 insertions, 3 deletions
diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c
index 431fdda21737..4ea4dd8a1eed 100644
--- a/block/blk-mq-sysfs.c
+++ b/block/blk-mq-sysfs.c
@@ -416,12 +416,14 @@ void blk_mq_hctx_kobj_init(struct blk_mq_hw_ctx *hctx)
static void blk_mq_sysfs_init(struct request_queue *q)
{
struct blk_mq_ctx *ctx;
- int i;
+ int cpu;
kobject_init(&q->mq_kobj, &blk_mq_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 050f7a13021b..1699baf39b78 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1798,11 +1798,12 @@ 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);