CVE-2024-26775: Improper Locking

In the Linux kernel, the following vulnerability has been resolved:

aoe: avoid potential deadlock at set_capacity

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.