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Message-ID: <280ee5e5.4936.18ee4d93bae.Coremail.congei42@163.com>
Date: Tue, 16 Apr 2024 11:00:25 +0800 (CST)
From: sicong <congei42@....com>
To: johan@...nel.org, elder@...nel.org, gregkh@...uxfoundation.org
Cc: greybus-dev@...ts.linaro.org, linux-kernel@...r.kernel.org
Subject: Bug report: greybus/interface.c: use-after-free bug in
gb_interface_release due to race condition
greybus/interface.c: use-after-free bug in gb_interface_release due to
race condition.
In gb_interface_create, &intf->mode_switch_completion is bound with
gb_interface_mode_switch_work. Then it will be started by
gb_interface_request_mode_switch. Here is the code.
if (!queue_work(system_long_wq, &intf->mode_switch_work)) {
...
}
If we call gb_interface_release to make cleanup, there may be an
unfinished work. This function will call kfree to free the object
"intf". However, if gb_interface_mode_switch_work is scheduled to
run after kfree, it may cause use-after-free error as
gb_interface_mode_switch_work will use the object "intf".
The possible execution flow that may lead to the issue is as follows:
CPU0 CPU1
| gb_interface_create
| gb_interface_request_mode_switch
gb_interface_release |
kfree(intf) (free) |
| gb_interface_mode_switch_work
| mutex_lock(&intf->mutex) (use)
This bug may be fixed by adding the following code before kfree.
cancel_work_sync(&intf->mode_switch_work);
Best regards,
Sicong Huang
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