Linus,
please pull the latest perf-urgent-for-linus git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git
perf-urgent-for-linus
A single fix clearing the TF bit when a fault is single stepped.
Thanks,
tglx
------------------>
Masami Hiramatsu (1):
kprobes/x86: Clear TF bit in fault on single-stepping
arch/x86/kernel/kprobes/core.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index 38cf7a741250..7847e5c0e0b5 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -961,7 +961,19 @@ int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
* normal page fault.
*/
regs->ip = (unsigned long)cur->addr;
+ /*
+ * Trap flag (TF) has been set here because this fault
+ * happened where the single stepping will be done.
+ * So clear it by resetting the current kprobe:
+ */
+ regs->flags &= ~X86_EFLAGS_TF;
+
+ /*
+ * If the TF flag was set before the kprobe hit,
+ * don't touch it:
+ */
regs->flags |= kcb->kprobe_old_flags;
+
if (kcb->kprobe_status == KPROBE_REENTER)
restore_previous_kprobe(kcb);
else
