On 7/8/21 5:52 AM, Saubhik Mukherjee wrote:

vtpm_module_init calls vtpmx_init which calls misc_register. The file
operations callbacks are registered. So, vtpmx_fops_ioctl can execute in
parallel with rest of vtpm_module_init. vtpmx_fops_ioctl calls
vtpmx_ioc_new_dev, which calls vtpm_proxy_create_device, which calls
vtpm_proxy_work_start, which could read uninitialized workqueue.

To avoid this, create workqueue before vtpmx init.

Found by Linux Driver Verification project (linuxtesting.org).

Fixes: 6f99612e2500 ("tpm: Proxy driver for supporting multiple emulated TPMs")
Signed-off-by: Saubhik Mukherjee <redacted>

Tested-by: Stefan Berger <stefanb@linux.ibm.com>