On Tue, Jun 29, 2021 at 08:27:00PM +0300, Jarkko Sakkinen wrote:
> On Wed, Jun 23, 2021 at 06:52:26PM +0530, 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).
> >
> > Signed-off-by: Saubhik Mukherjee <saubhik.mukherjee@xxxxxxxxx>
> > ---
> > drivers/char/tpm/tpm_vtpm_proxy.c | 19 +++++++++----------
> > 1 file changed, 9 insertions(+), 10 deletions(-)
> >
> > diff --git a/drivers/char/tpm/tpm_vtpm_proxy.c b/drivers/char/tpm/tpm_vtpm_proxy.c
> > index 91c772e38bb5..225dfa026a8f 100644
> > --- a/drivers/char/tpm/tpm_vtpm_proxy.c
> > +++ b/drivers/char/tpm/tpm_vtpm_proxy.c
> > @@ -697,23 +697,22 @@ static int __init vtpm_module_init(void)
> > {
> > int rc;
> >
> > - rc = vtpmx_init();
> > - if (rc) {
> > - pr_err("couldn't create vtpmx device\n");
> > - return rc;
> > - }
> > -
> > workqueue = create_workqueue("tpm-vtpm");
> > if (!workqueue) {
> > pr_err("couldn't create workqueue\n");
> > - rc = -ENOMEM;
> > - goto err_vtpmx_cleanup;
> > + return -ENOMEM;
> > + }
> > +
> > + rc = vtpmx_init();
> > + if (rc) {
> > + pr_err("couldn't create vtpmx device\n");
> > + goto err_destroy_workqueue;
> > }
> >
> > return 0;
> >
> > -err_vtpmx_cleanup:
> > - vtpmx_cleanup();
> > +err_destroy_workqueue:
> > + destroy_workqueue(workqueue);
> >
> > return rc;
> > }
> > --
> > 2.30.2
> >
> >
>
> Reviewed-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
Taking reviewed-by back.
You're lacking fixes tag. Please re-send with one.
/Jarkko
