Messages in this thread | | | Subject | Re: [PATCH] char: tpm: vtpm_proxy: Fix race in init | From | Saubhik Mukherjee <> | Date | Wed, 30 Jun 2021 12:54:30 +0530 |
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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)
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