Merge pull request #130 from AlphaDaze/datarace

Add data race detector plugin

dbm.h

@@ -274,6 +274,9 @@ struct dbm_thread_s {
   int pending_signals[_NSIG];
   uint32_t is_signal_pending;
   void *pstack;
+
+  // Can be utilised to trasnfer data to child thread
+  void *shared_parent_data;
 };
 
 typedef enum {

makefile

@@ -10,6 +10,8 @@
 #PLUGINS+=plugins/memcheck/memcheck.S plugins/memcheck/memcheck.c plugins/memcheck/naive_stdlib.c
 #PLUGINS+=plugins/follow_exec.c
 #PLUGINS+=plugins/hotspot.c
+#PLUGINS+=plugins/datarace/datarace.c plugins/datarace/detectors/fasttrack.c
+#PLUGINS+=plugins/datarace/datarace.c plugins/datarace/detectors/djit.c
 
 OPTS= -DDBM_LINK_UNCOND_IMM
 OPTS+=-DDBM_INLINE_UNCOND_IMM
@@ -87,6 +89,12 @@ pie:
 $(or $(OUTPUT_FILE),dbm): $(HEADERS) $(SOURCES) $(PLUGINS)
 	$(CC) $(CFLAGS) $(LDFLAGS) $(OPTS) $(INCLUDES) -o $@ $(SOURCES) $(PLUGINS) $(PIE) $(LIBS) $(PLUGIN_ARGS)
 
+datarace_ft:
+	PLUGINS="plugins/datarace/datarace.c plugins/datarace/detectors/fasttrack.c" CFLAGS="-DFASTTRACK" OUTPUT_FILE=mambo_datarace_ft make
+
+datarace_djit:
+	PLUGINS="plugins/datarace/datarace.c plugins/datarace/detectors/djit.c" CFLAGS="-DDJIT" OUTPUT_FILE=mambo_datarace_djit make
+
 cachesim:
 	PLUGINS="plugins/cachesim/cachesim.c plugins/cachesim/cachesim.S plugins/cachesim/cachesim_model.c" OUTPUT_FILE=mambo_cachesim make
 

plugins/datarace/README.md

@@ -0,0 +1,45 @@
+MAMBO datarace
+==============
+
+This instrumentation plugin for [MAMBO](https://github.com/beehive-lab/mambo) detects possible data races with relatively low performance overhead for programs that utilise POSIX pthreads. This is still experimental software, please report any bugs using GitHub's [issue tracker](https://github.com/beehive-lab/mambo/issues). Any improvements and fixes are also welcome with a [pull request.](https://github.com/beehive-lab/mambo/pulls)
+
+
+Building
+---------
+
+    git clone https://github.com/beehive-lab/mambo.git
+    cd mambo
+    make datarace_ft
+
+Usage
+------
+
+
+To run an application under MAMBO datarace, simply prefix the command with a call to `mambo_datarace_ft`. For example to execute `lscpu`, from the mambo source directory run:
+
+    ./mambo_datarace_ft /usr/bin/lscpu
+
+> **Note:** Underlying programs must be compiled with the `-no-pie` flag (can be linked statically or dynamically) OR must be dynamically linked with library at /usr/ and mambo compiled with `NO_PIE_ENABLE` disabled in [datarace.h](datarace.h). See limitations at the bottom for more information.
+
+
+Configuration
+-------------
+
+#### FastTrack and Djit+
+
+There are two separate algorithms to choose from for the datarace detector: [FastTrack](https://dl.acm.org/doi/abs/10.1145/1543135.1542490) and [DJIT+](https://dl.acm.org/doi/abs/10.1145/781498.781529). Both algorithms utilise the happens-before relationship. FastTrack is known to be an improvement over DJIT+ implementations by carrying out a happens-before comparison in O(1) for the majority of the cases compared to DJIT+'s O(n).
+
+> To compile and use the DJIT+ implementation, use `make datarace_djit` and run with `./mambo_datarace_djit`.
+
+#### Further configuration
+
+Further algorithms can be implemented using the handling functions for the various thread operations at the beginning of [datarace.c](datarace.c). Details of the implementation are also included at the top of the file for easier modification.
+
+[datarace.h](datarace.h) contains an option `no-pie` option enabled by default, to properly ignore libc. More debug information can also be enabled.
+
+Limitations
+------------
+
+The number of supported threads must be specified with `VC_INITIAL_SZ` in [detector.h](./detectors/detector.h) before compilation. It would be better to set this value to something like 4 or 8, and have it dynamically grow. This will require handling VC clocks of various sizes. Some work has been done for this feature in [fasttrack.c](./detectors/fasttrack.c) and commented out as a TODO to complete.
+
+Currently libc is ignored by not processing any reads/writes to addresses above `0x7000000000` which require the underlying program to be compiled with `no-pie`. A workaround involves dynamically linking to libc and not processing code within the /usr/ directory for data races. There is likely a better solution to this however. Please don't hesitate to open a [pull request](https://github.com/beehive-lab/mambo/pulls) for a fix or any other improvement.