This patch fixes a use-after-free that was introduced via patch
"blk-mq: fix hctx/ctx kobject use-after-free" (commit
76d697d10769; kernel v3.19-rc4) and fixes the following crash:
general protection fault: 0000 [#1] SMP
Workqueue: srp_remove srp_remove_work [ib_srp]
task: ffff88083530c880 ti: ffff880835774000 task.ti: ffff880835774000
[<ffffffff8125a43c>] blk_mq_tag_wakeup_all+0x1c/0x90
RDI: 6b6b6b6b6b6b6b6b
Call Trace:
[<ffffffff8125792e>] blk_mq_wake_waiters+0x4e/0x80
[<ffffffff81247e86>] blk_set_queue_dying+0x26/0x90
[<ffffffff8124abe5>] blk_cleanup_queue+0x35/0x250
[<ffffffffa001ce4a>] __scsi_remove_device+0x5a/0xe0 [scsi_mod]
[<ffffffffa001b48f>] scsi_forget_host+0x6f/0x80 [scsi_mod]
[<ffffffffa000d646>] scsi_remove_host+0x86/0x140 [scsi_mod]
[<ffffffffa0884c0b>] srp_remove_work+0x9b/0x210 [ib_srp]
[<ffffffff8106ff48>] process_one_work+0x1d8/0x780
[<ffffffff8107060b>] worker_thread+0x11b/0x460
[<ffffffff81075c8f>] kthread+0xef/0x110
[<ffffffff814dbdac>] ret_from_fork+0x7c/0xb0
Signed-off-by: Bart Van Assche <bart.vanass...@sandisk.com>
Cc: Ming Lei <ming....@canonical.com>
Cc: Sasha Levin <sasha.le...@oracle.com>
Cc: Christoph Hellwig <h...@lst.de>
---
block/blk-mq-sysfs.c | 15 +++++----------
block/blk-mq.c | 12 +++++++-----
2 files changed, 12 insertions(+), 15 deletions(-)
diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c
index 6774a0e..921f7cf 100644
--- a/block/blk-mq-sysfs.c
+++ b/block/blk-mq-sysfs.c
@@ -19,6 +19,8 @@ static void blk_mq_sysfs_release(struct kobject *kobj)
q = container_of(kobj, struct request_queue, mq_kobj);
free_percpu(q->queue_ctx);
+ kfree(q->queue_hw_ctx);
+ q->queue_hw_ctx = NULL;
}
static void blk_mq_ctx_release(struct kobject *kobj)
@@ -34,6 +36,7 @@ static void blk_mq_hctx_release(struct kobject *kobj)
struct blk_mq_hw_ctx *hctx;
hctx = container_of(kobj, struct blk_mq_hw_ctx, kobj);
+ kfree(hctx->ctxs);
kfree(hctx);
}
@@ -388,21 +391,13 @@ void blk_mq_unregister_disk(struct gendisk *disk)
{
struct request_queue *q = disk->queue;
struct blk_mq_hw_ctx *hctx;
- struct blk_mq_ctx *ctx;
- int i, j;
+ int i;
- queue_for_each_hw_ctx(q, hctx, i) {
+ queue_for_each_hw_ctx(q, hctx, i)
blk_mq_unregister_hctx(hctx);
- hctx_for_each_ctx(hctx, ctx, j)
- kobject_put(&ctx->kobj);
-
- kobject_put(&hctx->kobj);
- }
-
kobject_uevent(&q->mq_kobj, KOBJ_REMOVE);
kobject_del(&q->mq_kobj);
- kobject_put(&q->mq_kobj);
kobject_put(&disk_to_dev(disk)->kobj);
}
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 9ee3b87..6d007a4 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1604,7 +1604,8 @@ static void blk_mq_exit_hctx(struct request_queue *q,
struct blk_mq_tag_set *set,
struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx)
{
- unsigned flush_start_tag = set->queue_depth;
+ struct blk_mq_ctx *ctx;
+ unsigned j, flush_start_tag = set->queue_depth;
blk_mq_tag_idle(hctx);
@@ -1618,8 +1619,10 @@ static void blk_mq_exit_hctx(struct request_queue *q,
blk_mq_unregister_cpu_notifier(&hctx->cpu_notifier);
blk_free_flush_queue(hctx->fq);
- kfree(hctx->ctxs);
blk_mq_free_bitmap(&hctx->ctx_map);
+ hctx_for_each_ctx(hctx, ctx, j)
+ kobject_put(&ctx->kobj);
+ kobject_put(&hctx->kobj);
}
static void blk_mq_exit_hw_queues(struct request_queue *q,
@@ -2000,10 +2003,9 @@ void blk_mq_free_queue(struct request_queue *q)
percpu_ref_exit(&q->mq_usage_counter);
- kfree(q->queue_hw_ctx);
- kfree(q->mq_map);
+ kobject_put(&q->mq_kobj);
- q->queue_hw_ctx = NULL;
+ kfree(q->mq_map);
q->mq_map = NULL;
mutex_lock(&all_q_mutex);
--
2.1.2
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