Can you try if the following code can produce any meaningful results? I suggest you try this once in your original binary and then create a simple program calling the following code only (and only linking the .proto file without anything else in your project). If both fail (segfault), it might be a bug in protobuf generated code. If only the former fails, the problem should be somewhere else in your project (memory corruption bugs most likely).
LOG(INFO) << fm.GetDescriptor()->DebugString(); Note that you shouldn't change the generated code. It won't work. On Thu, May 22, 2014 at 9:28 AM, <[email protected]> wrote: > I am still experiencing this problem. Any help is highly appreciated, I > tried everything. > > The problem only occurs if bad data is fed to the parseFromString() > function. The following code crashes with a segmentation fault if > readBuffer contains bad data (currently, the content of > http://www.google.com). If readBuffer contains well-formed GTFS-realtime > data, everything works as expected: > > if (!(fm.ParseFromString(readBuffer))) { > LOG(WARNING) << "Failed to parse realtime GTFS."; > return; > } > > This is the line in the gtfs-realtime.pb.cc (in method > protobuf_AssignDesc_headers_2fprotobuf_2fgtfs_2drealtime_2eproto()) that > causes the crash: > > const ::google::protobuf::FileDescriptor* file = > ::google::protobuf::DescriptorPool::generated_pool()->FindFileByName( > "headers/protobuf/gtfs-realtime.proto"); > > For some reason, it tries to read the original .proto file if bad data is > received. I tried changing this line to an absolute path, but the problem > persists. The gtfs-realtime.proto file resides in headers/protobuf. protoc > is called like this: > > protoc -I=headers/protobuf --cpp_out=. > headers/protobuf/gtfs-realtime.proto > > I tried several locations for -cpp_out, but it didnt help. > > This is the valgrind output after the crash: > > ==4015== Invalid read of size 8 > ==4015== at 0x5108FF2: > google::protobuf::DescriptorPool::FindFileByName(std::string const&) const > (in /usr/lib/x86_64-linux-gnu/libprotobuf.so.8.0.0) > ==4015== by 0x47F3F4: > transit_realtime::protobuf_AssignDesc_gtfs_2drealtime_2eproto() (in > /home/patrick/repos/trajserver/trajhttpserv) > ==4015== by 0x50DC2CF: > google::protobuf::internal::FunctionClosure0::Run() (in > /usr/lib/x86_64-linux-gnu/libprotobuf.so.8.0.0) > ==4015== by 0x50DC4F0: google::protobuf::GoogleOnceInitImpl(long*, > google::protobuf::Closure*) (in > /usr/lib/x86_64-linux-gnu/libprotobuf.so.8.0.0) > ==4015== by 0x474444: transit_realtime::FeedMessage::GetMetadata() > const (in /home/patrick/repos/trajserver/trajhttpserv) > ==4015== by 0x513FF6F: google::protobuf::Message::GetTypeName() const > (in /usr/lib/x86_64-linux-gnu/libprotobuf.so.8.0.0) > ==4015== by 0x50EB090: ??? (in > /usr/lib/x86_64-linux-gnu/libprotobuf.so.8.0.0) > ==4015== by 0x50EB891: > google::protobuf::MessageLite::ParseFromString(std::string const&) (in > /usr/lib/x86_64-linux-gnu/libprotobuf.so.8.0.0) > ==4015== by 0x442E83: GtfsRealTimeReader::getTripUpdates() (in > /home/patrick/repos/trajserver/trajhttpserv) > ==4015== by 0x4824AB: > updateRealtimeReaders(std::vector<GtfsRealTimeReader, > std::allocator<GtfsRealTimeReader> >*, unsigned int) (in > /home/patrick/repos/trajserver/trajhttpserv) > ==4015== Address 0x0 is not stack'd, malloc'd or (recently) free'd > ==4015== > [22/05/2014 15:21:02,241645] FATAL: CRASH HANDLED; Application has crashed > due to [SIGSEGV] signal > > > Again, this crash happens every time I try to parse some random string as > a GTFS-realtime protobuf feed. > > I reproduced the segfault on three different machines: a Ubuntu 13.10 > machine with libprotoc 2.4.1, a Ubuntu 14.04 machine with libprotoc 2.5.0 > and a Debian machine with libprotoc 2.4.1. I tried different c++ version, > Ii tried -O1, -O2, -O3, I tried fixing the gtfs-realtime.pb.cc line by > hand, I played around with the protoc parameters, I compiled and installed > libprotoc 2.5.0 by hand on all 3 machines, I tried parsing the feed from a > stream and from a string, I created an application that only reads > http://www.google.com and feeds it to parseFromString() function - the > behaviour is always exactly the same: no problem on well-formed data, > segfault on bad data. > > I am using the original gtfs-realtime.proto file from the GTFS realtime > page. > > Anyone? > > > Am Freitag, 2. Mai 2014 15:29:48 UTC+2 schrieb [email protected]: > >> Hi, >> >> I am using a straightforward C++ client to fetch GTFS-realtime feeds. >> Feeds are read into a string with libcurl and than parsed: >> >> GOOGLE_PROTOBUF_VERIFY_VERSION; >> FeedMessage fm; >> >> /** fetching realtime feed with libcurl into readBuffer **/ >> >> if (!fm.ParseFromString(readBuffer)) { // this line crashes >> LOG(ERROR) << "Failed to parse realtime GTFS."; >> return; >> } >> >> I experience random segfault crashes during parsing. All of them oocure >> while parsing a very specific feed. The segfault is caused by >> >> google::protobuf::DescriptorPool::FindFileByName >> >> Backtrace: >> >> Program received signal SIGSEGV, Segmentation fault. >> #0 0x00007ffff7901f3e in >> google::protobuf::DescriptorPool::FindFileByName(std::string >> const&) const () from /usr/lib/libprotobuf.so.7 >> #1 0x000000000047e045 in transit_realtime::protobuf_ >> AssignDesc_headers_2fprotobuf_2fgtfs_2drealtime_2eproto() () at >> headers/protobuf/gtfs-realtime.pb.cc:80 >> #2 0x00007ffff7683400 in pthread_once () >> at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_once.S:104 >> #3 0x0000000000471593 in transit_realtime::FeedMessage::GetMetadata() >> const >> () at /usr/include/google/protobuf/stubs/once.h:115 >> #4 0x00007ffff7932274 in google::protobuf::Message::GetTypeName() const >> () >> from /usr/lib/libprotobuf.so.7 >> #5 0x00007ffff78e2f17 in ?? () from /usr/lib/libprotobuf.so.7 >> #6 0x00007ffff78e3714 in >> google::protobuf::MessageLite::ParseFromString(std::string >> const&) () from /usr/lib/libprotobuf.so.7 >> >> >> Since the segfaults are _always_ caused by the same feed, I strongly >> suspect that it is bad data that causes the crash. The random nature of the >> crashes could be explained by the feed returning a bad message every few >> few hours. Nevertheless, for bad data, ParseFromString() should return >> false, and not crash completely. >> >> I am using g++ 4.8.1 with -O3 -g -std=c++0x >> protoc --version returns "libprotoc 2.4.1" >> >> Thanks for any help :) >> >> >> >> >> >> >> -- > You received this message because you are subscribed to the Google Groups > "Protocol Buffers" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/protobuf. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Protocol Buffers" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/protobuf. 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