---

yaml --- r: 104384 b: refs/heads/master c: 380fdd7 h: refs/heads/master v: v3
git-mirror · Jul 16, 2008 · ba222d2 · ba222d2
1 parent 9eb4f0f
commit ba222d2
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Showing 4 changed files with 25 additions and 2 deletions.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: d4d67150165df8bf1cc05e532f6efca96f907cab
+refs/heads/master: 380fdd7585a4c2f41b48925eba85c0654b7b858b
diff --git a/trunk/arch/x86/kernel/ptrace.c b/trunk/arch/x86/kernel/ptrace.c
@@ -1416,6 +1416,16 @@ asmregparm long syscall_trace_enter(struct pt_regs *regs)
 {
 	long ret = 0;
 
+	/*
+	 * If we stepped into a sysenter/syscall insn, it trapped in
+	 * kernel mode; do_debug() cleared TF and set TIF_SINGLESTEP.
+	 * If user-mode had set TF itself, then it's still clear from
+	 * do_debug() and we need to set it again to restore the user
+	 * state.  If we entered on the slow path, TF was already set.
+	 */
+	if (test_thread_flag(TIF_SINGLESTEP))
+		regs->flags |= X86_EFLAGS_TF;
+
 	/* do the secure computing check first */
 	secure_computing(regs->orig_ax);
 

diff --git a/trunk/arch/x86/kernel/step.c b/trunk/arch/x86/kernel/step.c
@@ -107,6 +107,19 @@ static int enable_single_step(struct task_struct *child)
 	struct pt_regs *regs = task_pt_regs(child);
 	unsigned long oflags;
 
+	/*
+	 * If we stepped into a sysenter/syscall insn, it trapped in
+	 * kernel mode; do_debug() cleared TF and set TIF_SINGLESTEP.
+	 * If user-mode had set TF itself, then it's still clear from
+	 * do_debug() and we need to set it again to restore the user
+	 * state so we don't wrongly set TIF_FORCED_TF below.
+	 * If enable_single_step() was used last and that is what
+	 * set TIF_SINGLESTEP, then both TF and TIF_FORCED_TF are
+	 * already set and our bookkeeping is fine.
+	 */
+	if (unlikely(test_tsk_thread_flag(child, TIF_SINGLESTEP)))
+		regs->flags |= X86_EFLAGS_TF;
+
 	/*
 	 * Always set TIF_SINGLESTEP - this guarantees that
 	 * we single-step system calls etc..  This will also

diff --git a/trunk/include/asm-x86/thread_info.h b/trunk/include/asm-x86/thread_info.h
@@ -118,7 +118,7 @@ struct thread_info {
 /* work to do in syscall_trace_enter() */
 #define _TIF_WORK_SYSCALL_ENTRY	\
 	(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_EMU | \
-	 _TIF_SYSCALL_AUDIT | _TIF_SECCOMP)
+	 _TIF_SYSCALL_AUDIT | _TIF_SECCOMP | _TIF_SINGLESTEP)
 
 /* work to do in syscall_trace_leave() */
 #define _TIF_WORK_SYSCALL_EXIT	\