5.4-stable review patch. If anyone has any objections, please let me know.
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From: Sicong Huang congei42@163.com
commit 5c9c5d7f26acc2c669c1dcf57d1bb43ee99220ce upstream.
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 relevant 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)
Fix it by canceling the work before kfree.
Signed-off-by: Sicong Huang congei42@163.com Link: https://lore.kernel.org/r/20240416080313.92306-1-congei42@163.com Cc: Ronnie Sahlberg rsahlberg@ciq.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/greybus/interface.c | 1 + 1 file changed, 1 insertion(+)
--- a/drivers/greybus/interface.c +++ b/drivers/greybus/interface.c @@ -694,6 +694,7 @@ static void gb_interface_release(struct
trace_gb_interface_release(intf);
+ cancel_work_sync(&intf->mode_switch_work); kfree(intf); }