From: Saubhik Mukherjee <saubhik.mukherjee@gmail.com>
To: peterhuewe@gmx.de, jarkko@kernel.org, jgg@ziepe.ca
Cc: Saubhik Mukherjee <saubhik.mukherjee@gmail.com>,
linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org,
ldv-project@linuxtesting.org, andrianov@ispras.ru
Subject: [PATCH] char: tpm: vtpm_proxy: Fix race in init
Date: Wed, 23 Jun 2021 18:52:26 +0530 [thread overview]
Message-ID: <20210623132226.140341-1-saubhik.mukherjee@gmail.com> (raw)
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
next reply other threads:[~2021-06-23 13:22 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-23 13:22 Saubhik Mukherjee [this message]
2021-06-29 17:27 ` [PATCH] char: tpm: vtpm_proxy: Fix race in init Jarkko Sakkinen
2021-06-29 21:05 ` Jarkko Sakkinen
2021-06-30 7:14 ` Saubhik Mukherjee
2021-07-02 6:37 ` Jarkko Sakkinen
2021-06-30 7:24 ` Saubhik Mukherjee
2021-07-02 6:38 ` Jarkko Sakkinen
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