[PATCH] x86_64: Fix interaction of single stepping with debuggers
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 <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/x86_64/kernel/signal.c b/arch/x86_64/kernel/signal.c
index 4ff0f01..7760224 100644
--- a/arch/x86_64/kernel/signal.c
+++ b/arch/x86_64/kernel/signal.c
@@ -368,6 +368,18 @@
}
}
+ /*
+ * 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)