From 121c18244d67ae06db1979a27157ffe164855d83 Mon Sep 17 00:00:00 2001
From: Sumit Garg <sumit.garg@linaro.org>
Date: Tue, 4 Feb 2025 13:04:18 +0530
Subject: [PATCH] tee: optee: Fix supplicant wait loop
commit 70b0d6b0a199c5a3ee6c72f5e61681ed6f759612 upstream.
OP-TEE supplicant is a user-space daemon and it's possible for it
be hung or crashed or killed in the middle of processing an OP-TEE
RPC call. It becomes more complicated when there is incorrect shutdown
ordering of the supplicant process vs the OP-TEE client application which
can eventually lead to system hang-up waiting for the closure of the
client application.
Allow the client process waiting in kernel for supplicant response to
be killed rather than indefinitely waiting in an unkillable state. Also,
a normal uninterruptible wait should not have resulted in the hung-task
watchdog getting triggered, but the endless loop would.
This fixes issues observed during system reboot/shutdown when supplicant
got hung for some reason or gets crashed/killed which lead to client
getting hung in an unkillable state. It in turn lead to system being in
hung up state requiring hard power off/on to recover.
Fixes: 4fb0a5eb364d ("tee: add OP-TEE driver")
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Cc: stable@vger.kernel.org
Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Jens Wiklander <jens.wiklander@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/tee/optee/supp.c | 35 ++++++++---------------------------
1 file changed, 8 insertions(+), 27 deletions(-)
diff --git a/drivers/tee/optee/supp.c b/drivers/tee/optee/supp.c
index 322a543b8c278..d0f397c902420 100644
--- a/drivers/tee/optee/supp.c
+++ b/drivers/tee/optee/supp.c
@@ -80,7 +80,6 @@ u32 optee_supp_thrd_req(struct tee_context *ctx, u32 func, size_t num_params,
struct optee *optee = tee_get_drvdata(ctx->teedev);
struct optee_supp *supp = &optee->supp;
struct optee_supp_req *req;
- bool interruptable;
u32 ret;
/*
@@ -111,36 +110,18 @@ u32 optee_supp_thrd_req(struct tee_context *ctx, u32 func, size_t num_params,
/*
* Wait for supplicant to process and return result, once we've
* returned from wait_for_completion(&req->c) successfully we have
- * exclusive access again.
+ * exclusive access again. Allow the wait to be killable such that
+ * the wait doesn't turn into an indefinite state if the supplicant
+ * gets hung for some reason.
*/
- while (wait_for_completion_interruptible(&req->c)) {
+ if (wait_for_completion_killable(&req->c)) {
mutex_lock(&supp->mutex);
- interruptable = !supp->ctx;
- if (interruptable) {
- /*
- * There's no supplicant available and since the
- * supp->mutex currently is held none can
- * become available until the mutex released
- * again.
- *
- * Interrupting an RPC to supplicant is only
- * allowed as a way of slightly improving the user
- * experience in case the supplicant hasn't been
- * started yet. During normal operation the supplicant
- * will serve all requests in a timely manner and
- * interrupting then wouldn't make sense.
- */
- if (req->in_queue) {
- list_del(&req->link);
- req->in_queue = false;
- }
+ if (req->in_queue) {
+ list_del(&req->link);
+ req->in_queue = false;
}
mutex_unlock(&supp->mutex);
-
- if (interruptable) {
- req->ret = TEEC_ERROR_COMMUNICATION;
- break;
- }
+ req->ret = TEEC_ERROR_COMMUNICATION;
}
ret = req->ret;
--
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