commit d73020787e8730575b91bb010f0895571887970b
author Steven Moreland <smoreland@google.com> Sat May 15 01:32:04 2021 +0000
committer Steven Moreland <smoreland@google.com> Tue May 18 00:37:29 2021 +0000
tree 8f49da981b4f59f50922a843cde952babe69ffd1
parent 35626658834a9b4edcb47a09ca8b7e33d65c2e10

Revert^2 "libbinder: binder RPC - using getCalling* aborts"

15e2835588ce3a8e318c01230bda2c113a16f761

Broken code? Now you know!

Fixes: 186647790
Test: binderRpcTest (on host and device)

Change-Id: I994b007b76d68771519dc8279534616ec60e9d71

libs/binder/RpcState.cpp

diff --git a/libs/binder/RpcState.cpp b/libs/binder/RpcState.cpp
index 2ba9fa2..230de6f 100644
--- a/libs/binder/RpcState.cpp
+++ b/libs/binder/RpcState.cpp
@@ -18,7 +18,9 @@
 
 #include "RpcState.h"
 
+#include <android-base/scopeguard.h>
 #include <binder/BpBinder.h>
+#include <binder/IPCThreadState.h>
 #include <binder/RpcServer.h>
 
 #include "Debug.h"
@@ -28,6 +30,8 @@
 
 namespace android {
 
+using base::ScopeGuard;
+
 RpcState::RpcState() {}
 RpcState::~RpcState() {}
 
@@ -470,6 +474,21 @@
 
 status_t RpcState::processServerCommand(const base::unique_fd& fd, const sp<RpcSession>& session,
                                         const RpcWireHeader& command) {
+    IPCThreadState* kernelBinderState = IPCThreadState::selfOrNull();
+    IPCThreadState::SpGuard spGuard{
+            .address = __builtin_frame_address(0),
+            .context = "processing binder RPC command",
+    };
+    const IPCThreadState::SpGuard* origGuard;
+    if (kernelBinderState != nullptr) {
+        origGuard = kernelBinderState->pushGetCallingSpGuard(&spGuard);
+    }
+    ScopeGuard guardUnguard = [&]() {
+        if (kernelBinderState != nullptr) {
+            kernelBinderState->restoreGetCallingSpGuard(origGuard);
+        }
+    };
+
     switch (command.command) {
         case RPC_COMMAND_TRANSACT:
             return processTransact(fd, session, command);