On Wed, Jan 19, 2022 at 06:49:33PM +0100, Lars Persson wrote:
The addition of a shutdown hook by commit f25889f93184 ("optee: fix tee out of memory failure seen during kexec reboot") introduced a kernel shutdown regression that can be triggered after running the xtest suites.
Once the shutdown hook is called it is not possible to communicate any more with the supplicant process because the system is not scheduling task any longer. Thus if the optee driver shutdown path receives a supplicant RPC request from the OP-TEE we will deadlock the kernel's shutdown.
This unexpected event will in fact occur after the xtest suite has been run. It seems some cached SHM kept alive a context object which in turn kept alive a session towards a PTA or TA. Closing the session results in a socket RPC command being sent back from OP-TEE.
This sequence of events is captured by a 5.15 kernel annotated with extra prints:
Calling OPTEE_SMC_DISABLE_SHM_CACHE OPTEE_SMC_DISABLE_SHM_CACHE returned 0 freeing SHM ptr 0xFFFFFF8001079380 Calling OPTEE_SMC_DISABLE_SHM_CACHE OPTEE_SMC_DISABLE_SHM_CACHE returned 0 freeing SHM ptr 0xFFFFFF8001CC5580 Calling OPTEE_SMC_DISABLE_SHM_CACHE OPTEE_SMC_DISABLE_SHM_CACHE returned 0 freeing SHM ptr 0xFFFFFF8006308A80 Calling OPTEE_SMC_DISABLE_SHM_CACHE OPTEE_SMC_DISABLE_SHM_CACHE returned 0 freeing SHM ptr 0xFFFFFF8006308B00 optee: optee_handle_rpc: a0=0XFFFF0000 a1=0XA0 a2=0X0 optee: optee_handle_rpc: a0=0XFFFF0005 a1=0XFFFFFF80 a2=0X61E6500 optee: handle_rpc_func_cmd: cmd = 0XA optee_supp_thrd_req: func=0XA
Introduce a shutdown state in the optee device object to return an immediate error to all RPC requests in the shutdown path.
Fixes: f25889f93184 ("optee: fix tee out of memory failure seen during kexec reboot Signed-off-by: Lars Persson larper@axis.com
drivers/tee/optee/optee_private.h | 1 + drivers/tee/optee/smc_abi.c | 5 ++++- drivers/tee/optee/supp.c | 8 ++++++++ 3 files changed, 13 insertions(+), 1 deletion(-)
diff --git a/drivers/tee/optee/optee_private.h b/drivers/tee/optee/optee_private.h index 46f74ab07c7e..83380974ff44 100644 --- a/drivers/tee/optee/optee_private.h +++ b/drivers/tee/optee/optee_private.h @@ -164,6 +164,7 @@ struct optee { bool scan_bus_done; struct workqueue_struct *scan_bus_wq; struct work_struct scan_bus_work;
- bool shutting_down;
Please move this to right after "bool scan_bus_done" above to avoid unnecessary extra padding.
Thanks, Jens