From 34729f18667de94de2b95d7fa1f980e7020f3425 Mon Sep 17 00:00:00 2001 From: Li Li Date: Wed, 23 Nov 2022 12:16:54 -0800 Subject: [PATCH] BACKPORT: binder: return pending info for frozen async txns An async transaction to a frozen process will still be successfully put in the queue. But this pending async transaction won't be processed until the target process is unfrozen at an unspecified time in the future. Pass this important information back to the user space caller by returning BR_TRANSACTION_PENDING_FROZEN. Change-Id: I14a07cb4200b6c46f006ced28d1f367b3e67007a Signed-off-by: Li Li Acked-by: Carlos Llamas Link: https://lore.kernel.org/r/20221123201654.589322-2-dualli@chromium.org Signed-off-by: Greg Kroah-Hartman --- drivers/android/binder.c | 33 +++++++++++++++++++++++------ include/uapi/linux/android/binder.h | 7 +++++- 2 files changed, 33 insertions(+), 7 deletions(-) diff --git a/drivers/android/binder.c b/drivers/android/binder.c index 2f122dedcde9..bbf99d55afbc 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -190,7 +190,7 @@ enum binder_stat_types { }; struct binder_stats { - atomic_t br[_IOC_NR(BR_ONEWAY_SPAM_SUSPECT) + 1]; + atomic_t br[_IOC_NR(BR_TRANSACTION_PENDING_FROZEN) + 1]; atomic_t bc[_IOC_NR(BC_REPLY_SG) + 1]; atomic_t obj_created[BINDER_STAT_COUNT]; atomic_t obj_deleted[BINDER_STAT_COUNT]; @@ -244,6 +244,7 @@ struct binder_work { enum binder_work_type { BINDER_WORK_TRANSACTION = 1, BINDER_WORK_TRANSACTION_COMPLETE, + BINDER_WORK_TRANSACTION_PENDING, BINDER_WORK_TRANSACTION_ONEWAY_SPAM_SUSPECT, BINDER_WORK_RETURN_ERROR, BINDER_WORK_NODE, @@ -2928,7 +2929,10 @@ binder_find_outdated_transaction_ilocked(struct binder_transaction *t, * * Return: 0 if the transaction was successfully queued * BR_DEAD_REPLY if the target process or thread is dead - * BR_FROZEN_REPLY if the target process or thread is frozen + * BR_FROZEN_REPLY if the target process or thread is frozen and + * the sync transaction was rejected + * BR_TRANSACTION_PENDING_FROZEN if the target process is frozen + * and the async transaction was successfully queued */ static int binder_proc_transaction(struct binder_transaction *t, struct binder_proc *proc, @@ -2939,6 +2943,7 @@ static int binder_proc_transaction(struct binder_transaction *t, bool oneway = !!(t->flags & TF_ONE_WAY); bool pending_async = false; struct binder_transaction *t_outdated = NULL; + bool frozen = false; BUG_ON(!node); binder_node_lock(node); @@ -2956,11 +2961,12 @@ static int binder_proc_transaction(struct binder_transaction *t, binder_inner_proc_lock(proc); if (proc->is_frozen) { + frozen = true; proc->sync_recv |= !oneway; proc->async_recv |= oneway; } - if ((proc->is_frozen && !oneway) || proc->is_dead || + if ((frozen && !oneway) || proc->is_dead || (thread && thread->is_dead)) { bool proc_is_dead = proc->is_dead || (thread && thread->is_dead); @@ -2979,7 +2985,7 @@ static int binder_proc_transaction(struct binder_transaction *t, } else if (!pending_async) { binder_enqueue_work_ilocked(&t->work, &proc->todo); } else { - if ((t->flags & TF_UPDATE_TXN) && proc->is_frozen) { + if ((t->flags & TF_UPDATE_TXN) && frozen) { t_outdated = binder_find_outdated_transaction_ilocked(t, &node->async_todo); if (t_outdated) { @@ -3016,6 +3022,9 @@ static int binder_proc_transaction(struct binder_transaction *t, binder_stats_deleted(BINDER_STAT_TRANSACTION); } + if (oneway && frozen) + return BR_TRANSACTION_PENDING_FROZEN; + return 0; } @@ -3718,9 +3727,17 @@ static void binder_transaction(struct binder_proc *proc, } else { BUG_ON(target_node == NULL); BUG_ON(t->buffer->async_transaction != 1); - binder_enqueue_thread_work(thread, tcomplete); return_error = binder_proc_transaction(t, target_proc, NULL); - if (return_error) + /* + * Let the caller know when async transaction reaches a frozen + * process and is put in a pending queue, waiting for the target + * process to be unfrozen. + */ + if (return_error == BR_TRANSACTION_PENDING_FROZEN) + tcomplete->type = BINDER_WORK_TRANSACTION_PENDING; + binder_enqueue_thread_work(thread, tcomplete); + if (return_error && + return_error != BR_TRANSACTION_PENDING_FROZEN) goto err_dead_proc_or_thread; } if (target_thread) @@ -4463,10 +4480,13 @@ retry: binder_stat_br(proc, thread, e->cmd); } break; case BINDER_WORK_TRANSACTION_COMPLETE: + case BINDER_WORK_TRANSACTION_PENDING: case BINDER_WORK_TRANSACTION_ONEWAY_SPAM_SUSPECT: { if (proc->oneway_spam_detection_enabled && w->type == BINDER_WORK_TRANSACTION_ONEWAY_SPAM_SUSPECT) cmd = BR_ONEWAY_SPAM_SUSPECT; + else if (w->type == BINDER_WORK_TRANSACTION_PENDING) + cmd = BR_TRANSACTION_PENDING_FROZEN; else cmd = BR_TRANSACTION_COMPLETE; binder_inner_proc_unlock(proc); @@ -6184,6 +6204,7 @@ static const char * const binder_return_strings[] = { "BR_FAILED_REPLY", "BR_FROZEN_REPLY", "BR_ONEWAY_SPAM_SUSPECT", + "BR_TRANSACTION_PENDING_FROZEN" }; static const char * const binder_command_strings[] = { diff --git a/include/uapi/linux/android/binder.h b/include/uapi/linux/android/binder.h index 258cbf773943..608fb64828ca 100644 --- a/include/uapi/linux/android/binder.h +++ b/include/uapi/linux/android/binder.h @@ -503,7 +503,7 @@ enum binder_driver_return_protocol { BR_FROZEN_REPLY = _IO('r', 18), /* - * The target of the last transaction (either a bcTRANSACTION or + * The target of the last sync transaction (either a bcTRANSACTION or * a bcATTEMPT_ACQUIRE) is frozen. No parameters. */ @@ -513,6 +513,11 @@ enum binder_driver_return_protocol { * asynchronous transaction makes the allocated async buffer size exceed * detection threshold. No parameters. */ + + BR_TRANSACTION_PENDING_FROZEN = _IO('r', 20), + /* + * The target of the last async transaction is frozen. No parameters. + */ }; enum binder_driver_command_protocol {