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block: fix memory leaks on unplugging block device

All objects, which are allocated in blk_mq_register_disk, must be
released in blk_mq_unregister_disk.

I use a KVM virtual machine and virtio disk to reproduce this issue.

kmemleak: 18 new suspected memory leaks (see /sys/kernel/debug/kmemleak)
$ cat /sys/kernel/debug/kmemleak | head -n 30
unreferenced object 0xffff8800b6636150 (size 8):
  comm "kworker/0:2", pid 65, jiffies 4294809903 (age 86.358s)
  hex dump (first 8 bytes):
    76 69 72 74 69 6f 34 00                          virtio4.
  backtrace:
    [<ffffffff8165d41e>] kmemleak_alloc+0x4e/0xb0
    [<ffffffff8118cfc5>] __kmalloc_track_caller+0xf5/0x260
    [<ffffffff81155b11>] kstrdup+0x31/0x60
    [<ffffffff812242be>] sysfs_new_dirent+0x2e/0x140
    [<ffffffff81224678>] create_dir+0x38/0xe0
    [<ffffffff812249e3>] sysfs_create_dir_ns+0x73/0xc0
    [<ffffffff8130dfa9>] kobject_add_internal+0xc9/0x340
    [<ffffffff8130e535>] kobject_add+0x65/0xb0
    [<ffffffff813f34f8>] device_add+0x128/0x660
    [<ffffffff813f3a4a>] device_register+0x1a/0x20
    [<ffffffff813ae6f8>] register_virtio_device+0x98/0xe0
    [<ffffffff813b0cce>] virtio_pci_probe+0x12e/0x1c0
    [<ffffffff81340675>] local_pci_probe+0x45/0xa0
    [<ffffffff81341a51>] pci_device_probe+0x121/0x130
    [<ffffffff813f67f7>] driver_probe_device+0x87/0x390
    [<ffffffff813f6b3b>] __device_attach+0x3b/0x40
unreferenced object 0xffff8800b65aa1d8 (size 144):

Fixes: 320ae51fee (blk-mq: new multi-queue block IO queueing mechanism)
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
master
Andrey Vagin 8 years ago
committed by Jens Axboe
parent
commit
8515736604
  1. 13
      block/blk-mq-sysfs.c

13
block/blk-mq-sysfs.c

@ -335,9 +335,22 @@ static struct kobj_type blk_mq_hw_ktype = {
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;
queue_for_each_hw_ctx(q, hctx, i) {
hctx_for_each_ctx(hctx, ctx, j) {
kobject_del(&ctx->kobj);
kobject_put(&ctx->kobj);
}
kobject_del(&hctx->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);
}

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