diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/client/linux/handler/exception_handler.cc | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/src/client/linux/handler/exception_handler.cc b/src/client/linux/handler/exception_handler.cc index 55834e01..49aea360 100644 --- a/src/client/linux/handler/exception_handler.cc +++ b/src/client/linux/handler/exception_handler.cc @@ -549,6 +549,13 @@ bool ExceptionHandler::WriteMinidump(const string& dump_path, return eh.WriteMinidump(); } +// In order to making using EBP to calculate the desired value for ESP +// a valid operation, ensure that this function is compiled with a +// frame pointer using the following attribute. This attribute +// is supported on GCC but not on clang. +#if defined(__i386__) && defined(__GNUC__) && !defined(__clang__) +__attribute__((optimize("no-omit-frame-pointer"))) +#endif bool ExceptionHandler::WriteMinidump() { if (!IsOutOfProcess() && !minidump_descriptor_.IsFD()) { // Update the path of the minidump so that this can be called multiple times @@ -570,6 +577,29 @@ bool ExceptionHandler::WriteMinidump() { int getcontext_result = getcontext(&context.context); if (getcontext_result) return false; + +#if defined(__i386__) + // In CPUFillFromUContext in minidumpwriter.cc the stack pointer is retrieved + // from REG_UESP instead of from REG_ESP. REG_UESP is the user stack pointer + // and it only makes sense when running in kernel mode with a different stack + // pointer. When WriteMiniDump is called during normal processing REG_UESP is + // zero which leads to bad minidump files. + if (!context.context.uc_mcontext.gregs[REG_UESP]) { + // If REG_UESP is set to REG_ESP then that includes the stack space for the + // CrashContext object in this function, which is about 128 KB. Since the + // Linux dumper only records 32 KB of stack this would mean that nothing + // useful would be recorded. A better option is to set REG_UESP to REG_EBP, + // perhaps with a small negative offset in case there is any code that + // objects to them being equal. + context.context.uc_mcontext.gregs[REG_UESP] = + context.context.uc_mcontext.gregs[REG_EBP] - 16; + // The stack saving is based off of REG_ESP so it must be set to match the + // new REG_UESP. + context.context.uc_mcontext.gregs[REG_ESP] = + context.context.uc_mcontext.gregs[REG_UESP]; + } +#endif + #if !defined(__ARM_EABI__) // FPU state is not part of ARM EABI ucontext_t. memcpy(&context.float_state, context.context.uc_mcontext.fpregs, |