title: aoe: avoid potential deadlock at set_capacity
description: 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.
affected:
{
product: Linux
vendor: Linux
defaultStatus: unaffected
repo: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
versions:
version: 1da177e4c3f4, lessThan: 2d623c94fbba, status: affected, versionType: git
version: 1da177e4c3f4, lessThan: 673629018ba0, status: affected, versionType: git
version: 1da177e4c3f4, lessThan: 19a77b271638, status: affected, versionType: git
version: 1da177e4c3f4, lessThan: e169bd4fb2b3, status: affected, versionType: git
}
{
product: Linux
vendor: Linux
defaultStatus: affected
repo: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
versions:
version: 6.1.80, lessThanOrEqual: 6.1.*, status: unaffected, versionType: custom
version: 6.6.19, lessThanOrEqual: 6.6.*, status: unaffected, versionType: custom
version: 6.7.7, lessThanOrEqual: 6.7.*, status: unaffected, versionType: custom
version: 6.8, lessThanOrEqual: *, status: unaffected, versionType: original_commit_for_fix
}
