aoe: avoid potential deadlock at set_capacity
[ Upstream commit e169bd4fb2b36c4b2bee63c35c740c85daeb2e86 ] Move set_capacity() outside of the section procected by (&d->lock). To avoid possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- [1] lock(&bdev->bd_size_lock); local_irq_disable(); [2] lock(&d->lock); [3] lock(&bdev->bd_size_lock); <Interrupt> [4] lock(&d->lock); *** DEADLOCK *** Where [1](&bdev->bd_size_lock) hold by zram_add()->set_capacity(). [2]lock(&d->lock) hold by aoeblk_gdalloc(). And aoeblk_gdalloc() is trying to acquire [3](&bdev->bd_size_lock) at set_capacity() call. In this situation an attempt to acquire [4]lock(&d->lock) from aoecmd_cfg_rsp() will lead to deadlock. So the simplest solution is breaking lock dependency [2](&d->lock) -> [3](&bdev->bd_size_lock) by moving set_capacity() outside. Signed-off-by: Maksim Kiselev <bigunclemax@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20240124072436.3745720-2-bigunclemax@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
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@ -333,6 +333,7 @@ aoeblk_gdalloc(void *vp)
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struct gendisk *gd;
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mempool_t *mp;
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struct blk_mq_tag_set *set;
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sector_t ssize;
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ulong flags;
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int late = 0;
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int err;
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@ -395,7 +396,7 @@ aoeblk_gdalloc(void *vp)
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gd->minors = AOE_PARTITIONS;
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gd->fops = &aoe_bdops;
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gd->private_data = d;
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set_capacity(gd, d->ssize);
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ssize = d->ssize;
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snprintf(gd->disk_name, sizeof gd->disk_name, "etherd/e%ld.%d",
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d->aoemajor, d->aoeminor);
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@ -404,6 +405,8 @@ aoeblk_gdalloc(void *vp)
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spin_unlock_irqrestore(&d->lock, flags);
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set_capacity(gd, ssize);
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err = device_add_disk(NULL, gd, aoe_attr_groups);
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if (err)
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goto out_disk_cleanup;
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