From a833d31ad867103ba72a0b73f3606f4ab8601719 Mon Sep 17 00:00:00 2001 From: Sudeep Holla Date: Wed, 28 May 2025 09:49:41 +0100 Subject: firmware: arm_ffa: Fix memory leak by freeing notifier callback node Commit e0573444edbf ("firmware: arm_ffa: Add interfaces to request notification callbacks") adds support for notifier callbacks by allocating and inserting a callback node into a hashtable during registration of notifiers. However, during unregistration, the code only removes the node from the hashtable without freeing the associated memory, resulting in a memory leak. Resolve the memory leak issue by ensuring the allocated notifier callback node is properly freed after it is removed from the hashtable entry. Fixes: e0573444edbf ("firmware: arm_ffa: Add interfaces to request notification callbacks") Message-Id: <20250528-ffa_notif_fix-v1-1-5ed7bc7f8437@arm.com> Reviewed-by: Jens Wiklander Signed-off-by: Sudeep Holla --- drivers/firmware/arm_ffa/driver.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c index fe55613a8ea9..6f75cdf29720 100644 --- a/drivers/firmware/arm_ffa/driver.c +++ b/drivers/firmware/arm_ffa/driver.c @@ -1284,6 +1284,7 @@ update_notifier_cb(struct ffa_device *dev, int notify_id, void *cb, hash_add(drv_info->notifier_hash, &cb_info->hnode, notify_id); } else { hash_del(&cb_info->hnode); + kfree(cb_info); } return 0; -- cgit v1.2.3 From 27e850c88df0e25474a8caeb2903e2e90b62c1dc Mon Sep 17 00:00:00 2001 From: Sudeep Holla Date: Wed, 28 May 2025 09:49:42 +0100 Subject: firmware: arm_ffa: Move memory allocation outside the mutex locking The notifier callback node allocation is currently done while holding the notify_lock mutex. While this is safe even if memory allocation may sleep, we need to move the allocation outside the locked region in preparation to move from using muxtes to rwlocks. Move the memory allocation to avoid potential sleeping in atomic context once the locks are moved from mutex to rwlocks. Fixes: e0573444edbf ("firmware: arm_ffa: Add interfaces to request notification callbacks") Message-Id: <20250528-ffa_notif_fix-v1-2-5ed7bc7f8437@arm.com> Reviewed-by: Jens Wiklander Signed-off-by: Sudeep Holla --- drivers/firmware/arm_ffa/driver.c | 48 +++++++++++++++++++-------------------- 1 file changed, 24 insertions(+), 24 deletions(-) diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c index 6f75cdf29720..44eecb786e67 100644 --- a/drivers/firmware/arm_ffa/driver.c +++ b/drivers/firmware/arm_ffa/driver.c @@ -1250,13 +1250,12 @@ notifier_hnode_get_by_type(u16 notify_id, enum notify_type type) return NULL; } -static int -update_notifier_cb(struct ffa_device *dev, int notify_id, void *cb, - void *cb_data, bool is_registration, bool is_framework) +static int update_notifier_cb(struct ffa_device *dev, int notify_id, + struct notifier_cb_info *cb, bool is_framework) { struct notifier_cb_info *cb_info = NULL; enum notify_type type = ffa_notify_type_get(dev->vm_id); - bool cb_found; + bool cb_found, is_registration = !!cb; if (is_framework) cb_info = notifier_hnode_get_by_vmid_uuid(notify_id, dev->vm_id, @@ -1270,18 +1269,7 @@ update_notifier_cb(struct ffa_device *dev, int notify_id, void *cb, return -EINVAL; if (is_registration) { - cb_info = kzalloc(sizeof(*cb_info), GFP_KERNEL); - if (!cb_info) - return -ENOMEM; - - cb_info->dev = dev; - cb_info->cb_data = cb_data; - if (is_framework) - cb_info->fwk_cb = cb; - else - cb_info->cb = cb; - - hash_add(drv_info->notifier_hash, &cb_info->hnode, notify_id); + hash_add(drv_info->notifier_hash, &cb->hnode, notify_id); } else { hash_del(&cb_info->hnode); kfree(cb_info); @@ -1303,8 +1291,7 @@ static int __ffa_notify_relinquish(struct ffa_device *dev, int notify_id, mutex_lock(&drv_info->notify_lock); - rc = update_notifier_cb(dev, notify_id, NULL, NULL, false, - is_framework); + rc = update_notifier_cb(dev, notify_id, NULL, is_framework); if (rc) { pr_err("Could not unregister notification callback\n"); mutex_unlock(&drv_info->notify_lock); @@ -1335,6 +1322,7 @@ static int __ffa_notify_request(struct ffa_device *dev, bool is_per_vcpu, { int rc; u32 flags = 0; + struct notifier_cb_info *cb_info = NULL; if (ffa_notifications_disabled()) return -EOPNOTSUPP; @@ -1342,6 +1330,17 @@ static int __ffa_notify_request(struct ffa_device *dev, bool is_per_vcpu, if (notify_id >= FFA_MAX_NOTIFICATIONS) return -EINVAL; + cb_info = kzalloc(sizeof(*cb_info), GFP_KERNEL); + if (!cb_info) + return -ENOMEM; + + cb_info->dev = dev; + cb_info->cb_data = cb_data; + if (is_framework) + cb_info->fwk_cb = cb; + else + cb_info->cb = cb; + mutex_lock(&drv_info->notify_lock); if (!is_framework) { @@ -1349,21 +1348,22 @@ static int __ffa_notify_request(struct ffa_device *dev, bool is_per_vcpu, flags = PER_VCPU_NOTIFICATION_FLAG; rc = ffa_notification_bind(dev->vm_id, BIT(notify_id), flags); - if (rc) { - mutex_unlock(&drv_info->notify_lock); - return rc; - } + if (rc) + goto out_unlock_free; } - rc = update_notifier_cb(dev, notify_id, cb, cb_data, true, - is_framework); + rc = update_notifier_cb(dev, notify_id, cb_info, is_framework); if (rc) { pr_err("Failed to register callback for %d - %d\n", notify_id, rc); if (!is_framework) ffa_notification_unbind(dev->vm_id, BIT(notify_id)); } + +out_unlock_free: mutex_unlock(&drv_info->notify_lock); + if (rc) + kfree(cb_info); return rc; } -- cgit v1.2.3 From 9ca7a421229bbdfbe2e1e628cff5cfa782720a10 Mon Sep 17 00:00:00 2001 From: Sudeep Holla Date: Wed, 28 May 2025 09:49:43 +0100 Subject: firmware: arm_ffa: Replace mutex with rwlock to avoid sleep in atomic context MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The current use of a mutex to protect the notifier hashtable accesses can lead to issues in the atomic context. It results in the below kernel warnings: | BUG: sleeping function called from invalid context at kernel/locking/mutex.c:258 | in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 9, name: kworker/0:0 | preempt_count: 1, expected: 0 | RCU nest depth: 0, expected: 0 | CPU: 0 UID: 0 PID: 9 Comm: kworker/0:0 Not tainted 6.14.0 #4 | Workqueue: ffa_pcpu_irq_notification notif_pcpu_irq_work_fn | Call trace: | show_stack+0x18/0x24 (C) | dump_stack_lvl+0x78/0x90 | dump_stack+0x18/0x24 | __might_resched+0x114/0x170 | __might_sleep+0x48/0x98 | mutex_lock+0x24/0x80 | handle_notif_callbacks+0x54/0xe0 | notif_get_and_handle+0x40/0x88 | generic_exec_single+0x80/0xc0 | smp_call_function_single+0xfc/0x1a0 | notif_pcpu_irq_work_fn+0x2c/0x38 | process_one_work+0x14c/0x2b4 | worker_thread+0x2e4/0x3e0 | kthread+0x13c/0x210 | ret_from_fork+0x10/0x20 To address this, replace the mutex with an rwlock to protect the notifier hashtable accesses. This ensures that read-side locking does not sleep and multiple readers can acquire the lock concurrently, avoiding unnecessary contention and potential deadlocks. Writer access remains exclusive, preserving correctness. This change resolves warnings from lockdep about potential sleep in atomic context. Cc: Jens Wiklander Reported-by: Jérôme Forissier Closes: https://github.com/OP-TEE/optee_os/issues/7394 Fixes: e0573444edbf ("firmware: arm_ffa: Add interfaces to request notification callbacks") Message-Id: <20250528-ffa_notif_fix-v1-3-5ed7bc7f8437@arm.com> Reviewed-by: Jens Wiklander Tested-by: Jens Wiklander Signed-off-by: Sudeep Holla --- drivers/firmware/arm_ffa/driver.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c index 44eecb786e67..37eb2e6c2f9f 100644 --- a/drivers/firmware/arm_ffa/driver.c +++ b/drivers/firmware/arm_ffa/driver.c @@ -110,7 +110,7 @@ struct ffa_drv_info { struct work_struct sched_recv_irq_work; struct xarray partition_info; DECLARE_HASHTABLE(notifier_hash, ilog2(FFA_MAX_NOTIFICATIONS)); - struct mutex notify_lock; /* lock to protect notifier hashtable */ + rwlock_t notify_lock; /* lock to protect notifier hashtable */ }; static struct ffa_drv_info *drv_info; @@ -1289,19 +1289,19 @@ static int __ffa_notify_relinquish(struct ffa_device *dev, int notify_id, if (notify_id >= FFA_MAX_NOTIFICATIONS) return -EINVAL; - mutex_lock(&drv_info->notify_lock); + write_lock(&drv_info->notify_lock); rc = update_notifier_cb(dev, notify_id, NULL, is_framework); if (rc) { pr_err("Could not unregister notification callback\n"); - mutex_unlock(&drv_info->notify_lock); + write_unlock(&drv_info->notify_lock); return rc; } if (!is_framework) rc = ffa_notification_unbind(dev->vm_id, BIT(notify_id)); - mutex_unlock(&drv_info->notify_lock); + write_unlock(&drv_info->notify_lock); return rc; } @@ -1341,7 +1341,7 @@ static int __ffa_notify_request(struct ffa_device *dev, bool is_per_vcpu, else cb_info->cb = cb; - mutex_lock(&drv_info->notify_lock); + write_lock(&drv_info->notify_lock); if (!is_framework) { if (is_per_vcpu) @@ -1361,7 +1361,7 @@ static int __ffa_notify_request(struct ffa_device *dev, bool is_per_vcpu, } out_unlock_free: - mutex_unlock(&drv_info->notify_lock); + write_unlock(&drv_info->notify_lock); if (rc) kfree(cb_info); @@ -1407,9 +1407,9 @@ static void handle_notif_callbacks(u64 bitmap, enum notify_type type) if (!(bitmap & 1)) continue; - mutex_lock(&drv_info->notify_lock); + read_lock(&drv_info->notify_lock); cb_info = notifier_hnode_get_by_type(notify_id, type); - mutex_unlock(&drv_info->notify_lock); + read_unlock(&drv_info->notify_lock); if (cb_info && cb_info->cb) cb_info->cb(notify_id, cb_info->cb_data); @@ -1447,9 +1447,9 @@ static void handle_fwk_notif_callbacks(u32 bitmap) ffa_rx_release(); - mutex_lock(&drv_info->notify_lock); + read_lock(&drv_info->notify_lock); cb_info = notifier_hnode_get_by_vmid_uuid(notify_id, target, &uuid); - mutex_unlock(&drv_info->notify_lock); + read_unlock(&drv_info->notify_lock); if (cb_info && cb_info->fwk_cb) cb_info->fwk_cb(notify_id, cb_info->cb_data, buf); @@ -1974,7 +1974,7 @@ static void ffa_notifications_setup(void) goto cleanup; hash_init(drv_info->notifier_hash); - mutex_init(&drv_info->notify_lock); + rwlock_init(&drv_info->notify_lock); drv_info->notif_enabled = true; return; -- cgit v1.2.3 From 4c46a471be12216347ba707f8eadadbf5d68e698 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Tue, 3 Jun 2025 16:38:53 +0530 Subject: firmware: arm_ffa: Fix the missing entry in struct ffa_indirect_msg_hdr As per the spec, one 32 bit reserved entry is missing here, add it. Signed-off-by: Viresh Kumar Fixes: 910cc1acc9b4 ("firmware: arm_ffa: Add support for passing UUID in FFA_MSG_SEND2") Reviewed-by: Bertrand Marquis Message-Id: <28a624fbf416975de4fbe08cfbf7c2db89cb630e.1748948911.git.viresh.kumar@linaro.org> Signed-off-by: Sudeep Holla --- include/linux/arm_ffa.h | 1 + 1 file changed, 1 insertion(+) diff --git a/include/linux/arm_ffa.h b/include/linux/arm_ffa.h index 5bded24dc24f..e1634897e159 100644 --- a/include/linux/arm_ffa.h +++ b/include/linux/arm_ffa.h @@ -283,6 +283,7 @@ struct ffa_indirect_msg_hdr { u32 offset; u32 send_recv_id; u32 size; + u32 res1; uuid_t uuid; }; -- cgit v1.2.3