lkml.org 
[lkml]   [2021]   [Jun]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] char: tpm: vtpm_proxy: Fix race in init
From
Date
On 6/30/21 2:35 AM, Jarkko Sakkinen wrote:
> 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@gmail.com>
>>> ---
>>> 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@kernel.org>
>
> Taking reviewed-by back.
>
> You're lacking fixes tag. Please re-send with one.
>
> /Jarkko
>

Thank you for noticing. I sent the patch containing the Fixes tag in
reply to your last message. (https://lkml.org/lkml/2021/6/30/104)

\
 
 \ /
  Last update: 2021-06-30 09:25    [W:0.069 / U:0.172 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site