From 2af18f8e36b277730527cacc2256b1332f56aa28 Mon Sep 17 00:00:00 2001 From: Sudeep Holla Date: Tue, 28 Apr 2026 19:33:31 +0100 Subject: [PATCH] firmware: arm_ffa: Keep framework RX release under lock The framework notification handler drops rx_lock before issuing FFA_RX_RELEASE, leaving a window where another RX-buffer user can start a new FF-A transaction before ownership has actually been returned to firmware. Move the FFA_RX_RELEASE calls so they execute while rx_lock is still held on both the kmemdup() failure path and the normal success path. While doing that, switch the handler to scoped_guard() to keep the critical section explicit. Fixes: 285a5ea0f542 ("firmware: arm_ffa: Add support for handling framework notifications") Link: https://patch.msgid.link/20260428-ffa_fixes-v2-7-8595ae450034@kernel.org Signed-off-by: Sudeep Holla --- drivers/firmware/arm_ffa/driver.c | 29 +++++++++++++---------------- 1 file changed, 13 insertions(+), 16 deletions(-) diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c index 33b417e78684..d1e70866a425 100644 --- a/drivers/firmware/arm_ffa/driver.c +++ b/drivers/firmware/arm_ffa/driver.c @@ -1492,25 +1492,22 @@ static void handle_fwk_notif_callbacks(u32 bitmap) if (!(bitmap & FRAMEWORK_NOTIFY_RX_BUFFER_FULL)) return; - mutex_lock(&drv_info->rx_lock); + scoped_guard(mutex, &drv_info->rx_lock) { + msg = drv_info->rx_buffer; + buf = kmemdup((void *)msg + msg->offset, msg->size, GFP_KERNEL); + if (!buf) { + ffa_rx_release(); + return; + } - msg = drv_info->rx_buffer; - buf = kmemdup((void *)msg + msg->offset, msg->size, GFP_KERNEL); - if (!buf) { - mutex_unlock(&drv_info->rx_lock); - return; + target = SENDER_ID(msg->send_recv_id); + if (msg->offset >= sizeof(*msg)) + uuid_copy(&uuid, &msg->uuid); + else + uuid_copy(&uuid, &uuid_null); + ffa_rx_release(); } - target = SENDER_ID(msg->send_recv_id); - if (msg->offset >= sizeof(*msg)) - uuid_copy(&uuid, &msg->uuid); - else - uuid_copy(&uuid, &uuid_null); - - mutex_unlock(&drv_info->rx_lock); - - ffa_rx_release(); - read_lock(&drv_info->notify_lock); cb_info = notifier_hnode_get_by_vmid_uuid(notify_id, target, &uuid); read_unlock(&drv_info->notify_lock);