From: "Andi Kleen" Ported from i386/Linus Fix another TF corner case. Need to do the special TF handling for all signals to make debuggers happy Signed-off-by: Andi Kleen Signed-off-by: Andrew Morton --- 25-akpm/arch/x86_64/kernel/signal.c | 12 ++++++++++++ 1 files changed, 12 insertions(+) diff -puN arch/x86_64/kernel/signal.c~x86_64-fix-interaction-of-single-stepping-with-debuggers arch/x86_64/kernel/signal.c --- 25/arch/x86_64/kernel/signal.c~x86_64-fix-interaction-of-single-stepping-with-debuggers Thu Apr 7 15:10:49 2005 +++ 25-akpm/arch/x86_64/kernel/signal.c Thu Apr 7 15:10:49 2005 @@ -368,6 +368,18 @@ handle_signal(unsigned long sig, siginfo } } + /* + * If TF is set due to a debugger (PT_DTRACE), clear the TF + * flag so that register information in the sigcontext is + * correct. + */ + if (unlikely(regs->eflags & TF_MASK)) { + if (likely(current->ptrace & PT_DTRACE)) { + current->ptrace &= ~PT_DTRACE; + regs->eflags &= ~TF_MASK; + } + } + #ifdef CONFIG_IA32_EMULATION if (test_thread_flag(TIF_IA32)) { if (ka->sa.sa_flags & SA_SIGINFO) _