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https://github.com/FEX-Emu/linux.git
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binder: protect binder_ref with outer lock
Use proc->outer_lock to protect the binder_ref structure. The outer lock allows functions operating on the binder_ref to do nested acquires of node and inner locks as necessary to attach refs to nodes atomically. Binder refs must never be accesssed without holding the outer lock. Signed-off-by: Todd Kjos <tkjos@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Todd Kjos
Greg Kroah-Hartman
parent
b3e6861283
commit
2c1838dc68
@ -475,7 +475,9 @@ enum binder_deferred_state {
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* this proc ordered by node->ptr
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* (protected by @inner_lock)
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* @refs_by_desc: rbtree of refs ordered by ref->desc
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* (protected by @outer_lock)
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* @refs_by_node: rbtree of refs ordered by ref->node
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* (protected by @outer_lock)
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* @pid PID of group_leader of process
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* (invariant after initialized)
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* @tsk task_struct for group_leader of process
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@ -1269,8 +1271,8 @@ static void binder_put_node(struct binder_node *node)
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binder_dec_node_tmpref(node);
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}
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static struct binder_ref *binder_get_ref(struct binder_proc *proc,
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u32 desc, bool need_strong_ref)
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static struct binder_ref *binder_get_ref_olocked(struct binder_proc *proc,
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u32 desc, bool need_strong_ref)
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{
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struct rb_node *n = proc->refs_by_desc.rb_node;
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struct binder_ref *ref;
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@ -1293,7 +1295,7 @@ static struct binder_ref *binder_get_ref(struct binder_proc *proc,
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}
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/**
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* binder_get_ref_for_node() - get the ref associated with given node
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* binder_get_ref_for_node_olocked() - get the ref associated with given node
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* @proc: binder_proc that owns the ref
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* @node: binder_node of target
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* @new_ref: newly allocated binder_ref to be initialized or %NULL
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@ -1310,9 +1312,10 @@ static struct binder_ref *binder_get_ref(struct binder_proc *proc,
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* new_ref. new_ref must be kfree'd by the caller in
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* this case.
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*/
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static struct binder_ref *binder_get_ref_for_node(struct binder_proc *proc,
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struct binder_node *node,
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struct binder_ref *new_ref)
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static struct binder_ref *binder_get_ref_for_node_olocked(
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struct binder_proc *proc,
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struct binder_node *node,
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struct binder_ref *new_ref)
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{
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struct binder_context *context = proc->context;
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struct rb_node **p = &proc->refs_by_node.rb_node;
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@ -1375,7 +1378,7 @@ static struct binder_ref *binder_get_ref_for_node(struct binder_proc *proc,
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return new_ref;
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}
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static void binder_cleanup_ref(struct binder_ref *ref)
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static void binder_cleanup_ref_olocked(struct binder_ref *ref)
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{
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bool delete_node = false;
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@ -1418,17 +1421,17 @@ static void binder_cleanup_ref(struct binder_ref *ref)
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}
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/**
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* binder_inc_ref() - increment the ref for given handle
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* binder_inc_ref_olocked() - increment the ref for given handle
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* @ref: ref to be incremented
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* @strong: if true, strong increment, else weak
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* @target_list: list to queue node work on
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*
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* Increment the ref.
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* Increment the ref. @ref->proc->outer_lock must be held on entry
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*
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* Return: 0, if successful, else errno
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*/
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static int binder_inc_ref(struct binder_ref *ref, int strong,
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struct list_head *target_list)
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static int binder_inc_ref_olocked(struct binder_ref *ref, int strong,
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struct list_head *target_list)
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{
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int ret;
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@ -1457,12 +1460,9 @@ static int binder_inc_ref(struct binder_ref *ref, int strong,
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*
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* Decrement the ref.
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*
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* TODO: kfree is avoided here since an upcoming patch
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* will put this under a lock.
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*
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* Return: true if ref is cleaned up and ready to be freed
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*/
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static bool binder_dec_ref(struct binder_ref *ref, int strong)
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static bool binder_dec_ref_olocked(struct binder_ref *ref, int strong)
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{
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if (strong) {
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if (ref->data.strong == 0) {
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@ -1486,13 +1486,7 @@ static bool binder_dec_ref(struct binder_ref *ref, int strong)
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ref->data.weak--;
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}
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if (ref->data.strong == 0 && ref->data.weak == 0) {
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binder_cleanup_ref(ref);
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/*
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* TODO: we could kfree(ref) here, but an upcoming
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* patch will call this with a lock held, so we
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* return an indication that the ref should be
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* freed.
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*/
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binder_cleanup_ref_olocked(ref);
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return true;
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}
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return false;
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@ -1517,7 +1511,8 @@ static struct binder_node *binder_get_node_from_ref(
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struct binder_node *node;
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struct binder_ref *ref;
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ref = binder_get_ref(proc, desc, need_strong_ref);
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binder_proc_lock(proc);
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ref = binder_get_ref_olocked(proc, desc, need_strong_ref);
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if (!ref)
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goto err_no_ref;
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node = ref->node;
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@ -1528,10 +1523,12 @@ static struct binder_node *binder_get_node_from_ref(
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binder_inc_node_tmpref(node);
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if (rdata)
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*rdata = ref->data;
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binder_proc_unlock(proc);
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return node;
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err_no_ref:
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binder_proc_unlock(proc);
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return NULL;
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}
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@ -1571,24 +1568,27 @@ static int binder_update_ref_for_handle(struct binder_proc *proc,
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struct binder_ref *ref;
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bool delete_ref = false;
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ref = binder_get_ref(proc, desc, strong);
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binder_proc_lock(proc);
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ref = binder_get_ref_olocked(proc, desc, strong);
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if (!ref) {
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ret = -EINVAL;
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goto err_no_ref;
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}
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if (increment)
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ret = binder_inc_ref(ref, strong, NULL);
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ret = binder_inc_ref_olocked(ref, strong, NULL);
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else
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delete_ref = binder_dec_ref(ref, strong);
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delete_ref = binder_dec_ref_olocked(ref, strong);
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if (rdata)
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*rdata = ref->data;
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binder_proc_unlock(proc);
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if (delete_ref)
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binder_free_ref(ref);
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return ret;
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err_no_ref:
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binder_proc_unlock(proc);
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return ret;
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}
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@ -1633,15 +1633,19 @@ static int binder_inc_ref_for_node(struct binder_proc *proc,
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struct binder_ref *new_ref = NULL;
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int ret = 0;
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ref = binder_get_ref_for_node(proc, node, NULL);
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binder_proc_lock(proc);
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ref = binder_get_ref_for_node_olocked(proc, node, NULL);
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if (!ref) {
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binder_proc_unlock(proc);
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new_ref = kzalloc(sizeof(*ref), GFP_KERNEL);
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if (!new_ref)
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return -ENOMEM;
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ref = binder_get_ref_for_node(proc, node, new_ref);
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binder_proc_lock(proc);
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ref = binder_get_ref_for_node_olocked(proc, node, new_ref);
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}
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ret = binder_inc_ref(ref, strong, target_list);
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ret = binder_inc_ref_olocked(ref, strong, target_list);
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*rdata = ref->data;
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binder_proc_unlock(proc);
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if (new_ref && ref != new_ref)
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/*
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* Another thread created the ref first so
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@ -2497,11 +2501,14 @@ static void binder_transaction(struct binder_proc *proc,
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* stays alive until the transaction is
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* done.
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*/
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ref = binder_get_ref(proc, tr->target.handle, true);
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binder_proc_lock(proc);
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ref = binder_get_ref_olocked(proc, tr->target.handle,
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true);
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if (ref) {
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binder_inc_node(ref->node, 1, 0, NULL);
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target_node = ref->node;
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}
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binder_proc_unlock(proc);
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if (target_node == NULL) {
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binder_user_error("%d:%d got transaction to invalid handle\n",
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proc->pid, thread->pid);
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@ -3277,7 +3284,7 @@ static int binder_thread_write(struct binder_proc *proc,
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uint32_t target;
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binder_uintptr_t cookie;
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struct binder_ref *ref;
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struct binder_ref_death *death;
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struct binder_ref_death *death = NULL;
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if (get_user(target, (uint32_t __user *)ptr))
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return -EFAULT;
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@ -3285,7 +3292,29 @@ static int binder_thread_write(struct binder_proc *proc,
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if (get_user(cookie, (binder_uintptr_t __user *)ptr))
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return -EFAULT;
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ptr += sizeof(binder_uintptr_t);
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ref = binder_get_ref(proc, target, false);
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if (cmd == BC_REQUEST_DEATH_NOTIFICATION) {
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/*
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* Allocate memory for death notification
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* before taking lock
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*/
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death = kzalloc(sizeof(*death), GFP_KERNEL);
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if (death == NULL) {
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WARN_ON(thread->return_error.cmd !=
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BR_OK);
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thread->return_error.cmd = BR_ERROR;
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binder_enqueue_work(
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thread->proc,
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&thread->return_error.work,
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&thread->todo);
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binder_debug(
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BINDER_DEBUG_FAILED_TRANSACTION,
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"%d:%d BC_REQUEST_DEATH_NOTIFICATION failed\n",
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proc->pid, thread->pid);
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break;
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}
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}
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binder_proc_lock(proc);
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ref = binder_get_ref_olocked(proc, target, false);
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if (ref == NULL) {
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binder_user_error("%d:%d %s invalid ref %d\n",
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proc->pid, thread->pid,
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@ -3293,6 +3322,8 @@ static int binder_thread_write(struct binder_proc *proc,
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"BC_REQUEST_DEATH_NOTIFICATION" :
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"BC_CLEAR_DEATH_NOTIFICATION",
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target);
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binder_proc_unlock(proc);
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kfree(death);
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break;
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}
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@ -3310,20 +3341,8 @@ static int binder_thread_write(struct binder_proc *proc,
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if (ref->death) {
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binder_user_error("%d:%d BC_REQUEST_DEATH_NOTIFICATION death notification already set\n",
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proc->pid, thread->pid);
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break;
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}
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death = kzalloc(sizeof(*death), GFP_KERNEL);
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if (death == NULL) {
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WARN_ON(thread->return_error.cmd !=
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BR_OK);
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thread->return_error.cmd = BR_ERROR;
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binder_enqueue_work(
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thread->proc,
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&thread->return_error.work,
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&thread->todo);
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binder_debug(BINDER_DEBUG_FAILED_TRANSACTION,
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"%d:%d BC_REQUEST_DEATH_NOTIFICATION failed\n",
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proc->pid, thread->pid);
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binder_proc_unlock(proc);
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kfree(death);
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break;
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}
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binder_stats_created(BINDER_STAT_DEATH);
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@ -3356,6 +3375,7 @@ static int binder_thread_write(struct binder_proc *proc,
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binder_user_error("%d:%d BC_CLEAR_DEATH_NOTIFICATION death notification not active\n",
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proc->pid, thread->pid);
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binder_node_unlock(ref->node);
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binder_proc_unlock(proc);
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break;
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}
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death = ref->death;
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@ -3365,6 +3385,7 @@ static int binder_thread_write(struct binder_proc *proc,
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(u64)death->cookie,
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(u64)cookie);
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binder_node_unlock(ref->node);
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binder_proc_unlock(proc);
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break;
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}
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ref->death = NULL;
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@ -3391,6 +3412,7 @@ static int binder_thread_write(struct binder_proc *proc,
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binder_inner_proc_unlock(proc);
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binder_node_unlock(ref->node);
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}
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binder_proc_unlock(proc);
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} break;
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case BC_DEAD_BINDER_DONE: {
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struct binder_work *w;
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@ -4601,14 +4623,18 @@ static void binder_deferred_release(struct binder_proc *proc)
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binder_inner_proc_unlock(proc);
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outgoing_refs = 0;
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binder_proc_lock(proc);
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while ((n = rb_first(&proc->refs_by_desc))) {
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struct binder_ref *ref;
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ref = rb_entry(n, struct binder_ref, rb_node_desc);
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outgoing_refs++;
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binder_cleanup_ref(ref);
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binder_cleanup_ref_olocked(ref);
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binder_proc_unlock(proc);
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binder_free_ref(ref);
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binder_proc_lock(proc);
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}
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binder_proc_unlock(proc);
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binder_release_work(proc, &proc->todo);
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binder_release_work(proc, &proc->delivered_death);
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@ -4816,8 +4842,10 @@ static void print_binder_node_nilocked(struct seq_file *m,
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}
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}
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static void print_binder_ref(struct seq_file *m, struct binder_ref *ref)
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static void print_binder_ref_olocked(struct seq_file *m,
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struct binder_ref *ref)
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{
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WARN_ON(!spin_is_locked(&ref->proc->outer_lock));
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binder_node_lock(ref->node);
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seq_printf(m, " ref %d: desc %d %snode %d s %d w %d d %pK\n",
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ref->data.debug_id, ref->data.desc,
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@ -4869,11 +4897,14 @@ static void print_binder_proc(struct seq_file *m,
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binder_put_node(last_node);
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if (print_all) {
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binder_proc_lock(proc);
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for (n = rb_first(&proc->refs_by_desc);
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n != NULL;
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n = rb_next(n))
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print_binder_ref(m, rb_entry(n, struct binder_ref,
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rb_node_desc));
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print_binder_ref_olocked(m, rb_entry(n,
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struct binder_ref,
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rb_node_desc));
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binder_proc_unlock(proc);
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}
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binder_alloc_print_allocated(m, &proc->alloc);
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binder_inner_proc_lock(proc);
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@ -5013,6 +5044,7 @@ static void print_binder_proc_stats(struct seq_file *m,
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count = 0;
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strong = 0;
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weak = 0;
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binder_proc_lock(proc);
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for (n = rb_first(&proc->refs_by_desc); n != NULL; n = rb_next(n)) {
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struct binder_ref *ref = rb_entry(n, struct binder_ref,
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rb_node_desc);
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@ -5020,6 +5052,7 @@ static void print_binder_proc_stats(struct seq_file *m,
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strong += ref->data.strong;
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weak += ref->data.weak;
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}
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binder_proc_unlock(proc);
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seq_printf(m, " refs: %d s %d w %d\n", count, strong, weak);
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count = binder_alloc_get_allocated_count(&proc->alloc);
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