Issue 1304005: fix races in CrashGenerator::CreateChildCrash (Closed)
Descriptionfix races in CrashGenerator::CreateChildCrash The current CreateChildCrash logic is racy when it comes to creating a crash dump for two reasons: The main thread that calls kill() on a different thread is guaranteed the signal will be *queued* when it returns, but not *delivered*. If the kernel doesn't automatically schedule the receiving thread, but instead lets the main thread run to the exit() call, then the signal never triggers a coredump and the whole process simply exits. The main thread is using kill() to try to deliver a signal to a specific thread, but that function is for sending signals to a process. That means the kernel is free to deliver the signal to any thread in the process and not just the one requested. This manifests itself as the pr_pid in the coredump not being the one expected. Instead, we must use tkill() with the tid (which we already took care of gathering) to deliver to a specific thread. These are a lot easier to see on a UMP system as contention is heavier. BUG=chromium:207918 TEST=`dumper_unittest` still passes, and doesn't flake out in a UMP system TEST=`linux_client_unittest` still passes R=benchan@chromium.org Committed: https://code.google.com/p/google-breakpad/source/detail?r=1299 Patch Set 1 #Patch Set 2 : #
Total comments: 10
Patch Set 3 : #
MessagesTotal messages: 9
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