From a2b18708ee14baec4ef9c0fba96070bba14d0081 Mon Sep 17 00:00:00 2001 From: Todd Kjos Date: Wed, 5 Jul 2017 13:46:01 -0700 Subject: Revert "android: binder: Sanity check at binder ioctl" This reverts commit a906d6931f3ccaf7de805643190765ddd7378e27. The patch introduced a race in the binder driver. An attempt to fix the race was submitted in "[PATCH v2] android: binder: fix dangling pointer comparison", however the conclusion in the discussion for that patch was that the original patch should be reverted. The reversion is being done as part of the fine-grained locking patchset since the patch would need to be refactored when proc->vmm_vm_mm is removed from struct binder_proc and added in the binder allocator. Signed-off-by: Todd Kjos Cc: stable # 4.6+ Signed-off-by: Greg Kroah-Hartman --- drivers/android/binder.c | 5 ----- 1 file changed, 5 deletions(-) (limited to 'drivers/android/binder.c') diff --git a/drivers/android/binder.c b/drivers/android/binder.c index aae4d8d4be36..157bd3e49ff4 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -3247,10 +3247,6 @@ static long binder_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) /*pr_info("binder_ioctl: %d:%d %x %lx\n", proc->pid, current->pid, cmd, arg);*/ - if (unlikely(current->mm != proc->vma_vm_mm)) { - pr_err("current mm mismatch proc mm\n"); - return -EINVAL; - } trace_binder_ioctl(cmd, arg); ret = wait_event_interruptible(binder_user_error_wait, binder_stop_on_user_error < 2); @@ -3466,7 +3462,6 @@ static int binder_open(struct inode *nodp, struct file *filp) return -ENOMEM; get_task_struct(current); proc->tsk = current; - proc->vma_vm_mm = current->mm; INIT_LIST_HEAD(&proc->todo); init_waitqueue_head(&proc->wait); proc->default_priority = task_nice(current); -- cgit v1.2.1 From c4ea41ba195d01c9af66fb28711a16cc97caa9c5 Mon Sep 17 00:00:00 2001 From: Todd Kjos Date: Thu, 29 Jun 2017 12:01:36 -0700 Subject: binder: use group leader instead of open thread The binder allocator assumes that the thread that called binder_open will never die for the lifetime of that proc. That thread is normally the group_leader, however it may not be. Use the group_leader instead of current. Signed-off-by: Todd Kjos Cc: stable # 4.4+ Signed-off-by: Greg Kroah-Hartman --- drivers/android/binder.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/android/binder.c') diff --git a/drivers/android/binder.c b/drivers/android/binder.c index 157bd3e49ff4..9393924ae8e8 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -3460,8 +3460,8 @@ static int binder_open(struct inode *nodp, struct file *filp) proc = kzalloc(sizeof(*proc), GFP_KERNEL); if (proc == NULL) return -ENOMEM; - get_task_struct(current); - proc->tsk = current; + get_task_struct(current->group_leader); + proc->tsk = current->group_leader; INIT_LIST_HEAD(&proc->todo); init_waitqueue_head(&proc->wait); proc->default_priority = task_nice(current); -- cgit v1.2.1 From 00b40d613352c623aaae88a44e5ded7c912909d7 Mon Sep 17 00:00:00 2001 From: Riley Andrews Date: Thu, 29 Jun 2017 12:01:37 -0700 Subject: binder: Use wake up hint for synchronous transactions. Use wake_up_interruptible_sync() to hint to the scheduler binder transactions are synchronous wakeups. Disable preemption while waking to avoid ping-ponging on the binder lock. Signed-off-by: Todd Kjos Signed-off-by: Omprakash Dhyade Cc: stable # 4.4+ Signed-off-by: Greg Kroah-Hartman --- drivers/android/binder.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'drivers/android/binder.c') diff --git a/drivers/android/binder.c b/drivers/android/binder.c index 9393924ae8e8..f7665c31feca 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -2200,8 +2200,12 @@ static void binder_transaction(struct binder_proc *proc, list_add_tail(&t->work.entry, target_list); tcomplete->type = BINDER_WORK_TRANSACTION_COMPLETE; list_add_tail(&tcomplete->entry, &thread->todo); - if (target_wait) - wake_up_interruptible(target_wait); + if (target_wait) { + if (reply || !(t->flags & TF_ONE_WAY)) + wake_up_interruptible_sync(target_wait); + else + wake_up_interruptible(target_wait); + } return; err_translate_failed: -- cgit v1.2.1