Prevent app fuse from indefinitely trying if it gets ENOBUFS
When there is not enough memory to allocate the appfuse socket,
ENOBUFS error could occur repeatly, and the retry will not be ended.
Limit the retry count to prevent infinite repetition.
Limited this to take only 5 seconds which is still quite high but still
better than running indefinitely. We can reduce this further later on.
Test: Manual
Bug: 312503249
Bug: 369519866
Change-Id: I928b7b5e6d0a53831c2b35d48aeb9440e8f6564a
diff --git a/libappfuse/FuseBuffer.cc b/libappfuse/FuseBuffer.cc
index 1915f22..269f300 100644
--- a/libappfuse/FuseBuffer.cc
+++ b/libappfuse/FuseBuffer.cc
@@ -35,6 +35,8 @@
namespace {
constexpr useconds_t kRetrySleepForWriting = 1000; // 1 ms
+// This makes the total wait time to allocate a buffer 5 seconds
+const int kNumberOfRetriesForWriting = 5000;
template <typename T>
bool CheckHeaderLength(const FuseMessage<T>* self, const char* name, size_t max_size) {
@@ -92,6 +94,7 @@
const char* const buf = reinterpret_cast<const char*>(self);
const auto& header = static_cast<const T*>(self)->header;
+ int retry = kNumberOfRetriesForWriting;
while (true) {
int result;
@@ -110,8 +113,14 @@
case ENOBUFS:
// When returning ENOBUFS, epoll still reports the FD is writable. Just usleep
// and retry again.
- usleep(kRetrySleepForWriting);
- continue;
+ if (retry > 0) {
+ usleep(kRetrySleepForWriting);
+ retry--;
+ continue;
+ } else {
+ LOG(ERROR) << "Failed to write a FUSE message: ENOBUFS retries are failed";
+ return ResultOrAgain::kFailure;
+ }
case EAGAIN:
return ResultOrAgain::kAgain;
default: