On Darwin, sigprocmask changes the signal mask for the entire process. This has some unwanted consequences, because e.g. internal_start_thread wants to disable signals only in the current thread (to make the new thread inherit the signal mask), which is currently broken on Darwin. This patch switches to pthread_sigmask.
Differential Revision: https://reviews.llvm.org/D35016
llvm-svn: 307212
This patch allows the Swift compiler to emit calls to `__tsan_external_write` before starting any modifying access, which will cause TSan to detect races on arrays, dictionaries and other classes defined in non-instrumented modules. Races on collections from the Swift standard library and user-defined structs and a frequent cause of subtle bugs and it's important that TSan detects those on top of existing LLVM IR instrumentation, which already detects races in direct memory accesses.
Differential Revision: https://reviews.llvm.org/D31630
llvm-svn: 302050
We need to make sure that the "external" API isn't dup'ing all data races into a single one (because the stack might look the same) and suppressing all external races. This works now, so just adding a test for that.
Differential Revision: https://reviews.llvm.org/D31734
llvm-svn: 301011
On Darwin, the setting ignore_noninstrumented_modules is used to suppress false positives in code that users don't have control of. The recently added "external" API (which can be used to detect races on objects provided by system libraries, but the race is actually user's fault) ignores this flag and it can report issues in non-instrumented modules. This patch fixes that.
Differential Revision: https://reviews.llvm.org/D31553
llvm-svn: 301000
This patch make sure we don't report deadlocks and other bug types when we're inside an interceptor that was called from a noninstrumented module (when ignore_noninstrumented_modules=1 is set). Adding a testcase that shows that deadlock detection still works on Darwin (to make sure we're not silencing too many reports).
Differential Revision: https://reviews.llvm.org/D31449
llvm-svn: 300998
We seem to assume that OS-provided thread IDs are either uptr or int, neither of which is true on Darwin. This introduces a tid_t type, which holds a OS-provided thread ID (gettid on Linux, pthread_threadid_np on Darwin, pthread_self on FreeBSD).
Differential Revision: https://reviews.llvm.org/D31774
llvm-svn: 300473
TSan reports a false positive when using xpc_connection_cancel. We're missing a happens-before edge from xpc_connection_cancel to the event handler on the same connection.
Differential Revision: https://reviews.llvm.org/D31475
llvm-svn: 299086
While it's usually a bug to call GCD APIs, such as dispatch_after, with NULL as a queue, this often "somehow" works and TSan should maintain binary compatibility with existing code. This patch makes sure we don't try to call Acquire and Release on NULL queues, and add one such testcase for dispatch_after.
Differential Revision: https://reviews.llvm.org/D31355
llvm-svn: 298820
This patch allows a non-instrumented library to call into TSan runtime, and tell us about "readonly" and "modifying" accesses to an arbitrary "object" and provide the caller and tag (type of object). This allows TSan to detect violations of API threading contracts where "read-only" methods can be called simulatenously from multiple threads, while modifying methods must be exclusive.
Differential Revision: https://reviews.llvm.org/D28836
llvm-svn: 293885
When dealing with GCD worker threads, TSan currently prints weird things like "created by thread T-1" and "[failed to restore the stack]" in reports. This patch avoids that and instead prints "Thread T3 (...) is a GCD worker thread".
Differential Revision: https://reviews.llvm.org/D29103
llvm-svn: 293882
Currently, os_id of the main thread contains the PID instead of a thread ID. Let's fix this.
Differential Revision: https://reviews.llvm.org/D29106
llvm-svn: 293201
TSan recently got the "ignore_noninstrumented_modules" flag, which disables tracking of read and writes that come from noninstrumented modules (via interceptors). This is a way of suppressing false positives coming from system libraries and other noninstrumented code. This patch turns this on by default on Darwin, where it's supposed to replace the previous solution, "ignore_interceptors_accesses", which disables tracking in *all* interceptors. The new approach should re-enable TSan's ability to find races via interceptors on Darwin.
Differential Revision: https://reviews.llvm.org/D29041
llvm-svn: 292981
On Darwin, we currently use 'ignore_interceptors_accesses', which is a heavy-weight solution that simply turns of race detection in all interceptors. This was done to suppress false positives coming from system libraries (non-instrumented code), but it also silences a lot of real races. This patch implements an alternative approach that should allow us to enable interceptors and report races coming from them, but only if they are called directly from instrumented code.
The patch matches the caller PC in each interceptors. For non-instrumented code, we call ThreadIgnoreBegin.
The assumption here is that the number of instrumented modules is low. Most likely there's only one (the instrumented main executable) and all the other modules are system libraries (non-instrumented).
Differential Revision: https://reviews.llvm.org/D28264
llvm-svn: 291631
We already have an interceptor for __shared_weak_count::__release_shared, this patch handles __shared_count::__release_shared in the same way. This should get rid of TSan false positives when using std::future.
Differential Revision: https://reviews.llvm.org/D27797
llvm-svn: 289831
GCD queues can be suspended and resumed with dispatch_suspend and dispatch_resume. We need to add synchronization between the call to dispatch_resume and any subsequent executions of blocks in the queue that was resumed. We already have an Acquire(q) before the block executes, so this patch just adds the Release(q) in an interceptor of dispatch_resume.
Differential Revision: https://reviews.llvm.org/D27112
llvm-svn: 287902
Although rare, atomic accesses to floating-point types seem to be valid, i.e. `%a = load atomic float ...`. The TSan instrumentation pass however tries to emit inttoptr, which is incorrect, we should use a bitcast here. Anyway, IRBuilder already has a convenient helper function for this.
Differential Revision: https://reviews.llvm.org/D26266
llvm-svn: 286136
GCD (libdispatch) has a concept of “target queues”: Each queue has either an implicit or explicit target queue, where the task is handed over to when it’s time to execute it. For example, a concurrent queue can have a serial target queue (effectively making the first queue serial), or multiple queues can have the same serial target queue (which means tasks in all the queues are mutually excluded). Thus we need to acquire-release semantics on the full “chain” of target queues.
This patch changes the way we Acquire() and Release() when executing tasks in queues. Now we’ll walk the chain of target queues and synchronize on each queue that is serial (or when dealing with a barrier block). This should avoid false positives when using dispatch_set_target_queue().
Differential Revision: https://reviews.llvm.org/D25835
llvm-svn: 285613
This patch adds a wrapper for call_once, which uses an already-compiled helper __call_once with an atomic release which is invisible to TSan. To avoid false positives, the interceptor performs an explicit atomic release in the callback wrapper.
Differential Revision: https://reviews.llvm.org/D24188
llvm-svn: 280920
The system implementation of OSAtomicTestAndClear returns the original bit, but the TSan interceptor has a bug which always returns zero from the function. This patch fixes this and adds a test.
Differential Revision: https://reviews.llvm.org/D23061
llvm-svn: 277461
On Darwin, there are some apps that rely on realloc(nullptr, 0) returning a valid pointer. TSan currently returns nullptr in this case, let's fix it to avoid breaking binary compatibility.
Differential Revision: https://reviews.llvm.org/D22800
llvm-svn: 277458
This patch adds interceptors for dispatch_io_*, dispatch_read and dispatch_write functions. This avoids false positives when using GCD IO. Adding several test cases.
Differential Revision: http://reviews.llvm.org/D21889
llvm-svn: 275071
These test in this change are objc++, but are built using %clang, not %clangxx.
The reason this works is the driver has been adding -lc++ for sanitizer enabled
builds. By making these tests use %clangxx, they no longer depend on the driver
linking to c++. Doing so will allow us to prevent overlinking of libc++ for
applications.
llvm-svn: 274989
This patch adds synchronization between the creation of the GCD data object and destructor’s execution. It’s far from perfect, because ideally we’d want to synchronize the destruction of the last reference (via dispatch_release) and the destructor’s execution, but intercepting objc_release is problematic.
Differential Revision: http://reviews.llvm.org/D21990
llvm-svn: 274749
We already have interceptors for dispatch_source API (e.g. dispatch_source_set_event_handler), but they currently only handle submission synchronization. We also need to synchronize based on the target queue (serial, concurrent), in other words, we need to use dispatch_callback_wrap. This patch implements that.
Differential Revision: http://reviews.llvm.org/D21999
llvm-svn: 274619
In the patch that introduced support for GCD barrier blocks, I removed releasing a group when leaving it (in dispatch_group_leave). However, this is necessary to synchronize leaving a group and a notification callback (dispatch_group_notify). Adding this back, simplifying dispatch_group_notify_f and adding a test case.
Differential Revision: http://reviews.llvm.org/D21927
llvm-svn: 274549
Because we use SCOPED_TSAN_INTERCEPTOR in the dispatch_once interceptor, the original dispatch_once can also be sometimes called (when ignores are enabled or when thr->is_inited is false). However the original dispatch_once function doesn’t expect to find “2” in the storage and it will spin forever (but we use “2” to indicate that the initialization is already done, so no waiting is necessary). This patch makes sure we never call the original dispatch_once.
Differential Revision: http://reviews.llvm.org/D21976
llvm-svn: 274548
The dispatch_group_async interceptor actually extends the lifetime of the executed block. This means the destructor of the block (and captured variables) is called *after* dispatch_group_leave, which changes the semantics of dispatch_group_async. This patch fixes that.
Differential Revision: http://reviews.llvm.org/D21816
llvm-svn: 274117
Adding support for GCD barrier blocks in concurrent queues. This uses two sync object in the same way as read-write locks do. This also simplifies the use of dispatch groups (the notifications act as barrier blocks).
Differential Revision: http://reviews.llvm.org/D21604
llvm-svn: 273893
There is a "well-known" TSan false positive when using C++ weak_ptr/shared_ptr and code in destructors, e.g. described at <https://llvm.org/bugs/show_bug.cgi?id=22324>. The "standard" solution is to build and use a TSan-instrumented version of libcxx, which is not trivial for end-users. This patch tries a different approach (on OS X): It adds an interceptor for the specific function in libc++.dylib, which implements the atomic operation that needs to be visible to TSan.
Differential Revision: http://reviews.llvm.org/D21609
llvm-svn: 273806
We're missing interceptors for dispatch_after and dispatch_after_f. Let's add them to avoid false positives. Added a test case.
Differential Revision: http://reviews.llvm.org/D20426
llvm-svn: 270071
Kuba Mracek