1 files changed, 36 insertions, 31 deletions

diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index 7079ddaf0731..017d937639fe 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -509,14 +509,14 @@ static int genregs_get(struct task_struct *target,
 {
 	if (kbuf) {
 		unsigned long *k = kbuf;
-		while (count > 0) {
+		while (count >= sizeof(*k)) {
 			*k++ = getreg(target, pos);
 			count -= sizeof(*k);
 			pos += sizeof(*k);
 		}
 	} else {
 		unsigned long __user *u = ubuf;
-		while (count > 0) {
+		while (count >= sizeof(*u)) {
 			if (__put_user(getreg(target, pos), u++))
 				return -EFAULT;
 			count -= sizeof(*u);
@@ -535,14 +535,14 @@ static int genregs_set(struct task_struct *target,
 	int ret = 0;
 	if (kbuf) {
 		const unsigned long *k = kbuf;
-		while (count > 0 && !ret) {
+		while (count >= sizeof(*k) && !ret) {
 			ret = putreg(target, pos, *k++);
 			count -= sizeof(*k);
 			pos += sizeof(*k);
 		}
 	} else {
 		const unsigned long  __user *u = ubuf;
-		while (count > 0 && !ret) {
+		while (count >= sizeof(*u) && !ret) {
 			unsigned long word;
 			ret = __get_user(word, u++);
 			if (ret)
@@ -1458,14 +1458,14 @@ static int genregs32_get(struct task_struct *target,
 {
 	if (kbuf) {
 		compat_ulong_t *k = kbuf;
-		while (count > 0) {
+		while (count >= sizeof(*k)) {
 			getreg32(target, pos, k++);
 			count -= sizeof(*k);
 			pos += sizeof(*k);
 		}
 	} else {
 		compat_ulong_t __user *u = ubuf;
-		while (count > 0) {
+		while (count >= sizeof(*u)) {
 			compat_ulong_t word;
 			getreg32(target, pos, &word);
 			if (__put_user(word, u++))
@@ -1486,14 +1486,14 @@ static int genregs32_set(struct task_struct *target,
 	int ret = 0;
 	if (kbuf) {
 		const compat_ulong_t *k = kbuf;
-		while (count > 0 && !ret) {
+		while (count >= sizeof(*k) && !ret) {
 			ret = putreg32(target, pos, *k++);
 			count -= sizeof(*k);
 			pos += sizeof(*k);
 		}
 	} else {
 		const compat_ulong_t __user *u = ubuf;
-		while (count > 0 && !ret) {
+		while (count >= sizeof(*u) && !ret) {
 			compat_ulong_t word;
 			ret = __get_user(word, u++);
 			if (ret)
@@ -1676,21 +1676,33 @@ const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 #endif
 }
 
-void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs,
-					 int error_code, int si_code)
+static void fill_sigtrap_info(struct task_struct *tsk,
+				struct pt_regs *regs,
+				int error_code, int si_code,
+				struct siginfo *info)
 {
-	struct siginfo info;
-
 	tsk->thread.trap_no = 1;
 	tsk->thread.error_code = error_code;
 
-	memset(&info, 0, sizeof(info));
-	info.si_signo = SIGTRAP;
-	info.si_code = si_code;
+	memset(info, 0, sizeof(*info));
+	info->si_signo = SIGTRAP;
+	info->si_code = si_code;
+	info->si_addr = user_mode_vm(regs) ? (void __user *)regs->ip : NULL;
+}
 
-	/* User-mode ip? */
-	info.si_addr = user_mode_vm(regs) ? (void __user *) regs->ip : NULL;
+void user_single_step_siginfo(struct task_struct *tsk,
+				struct pt_regs *regs,
+				struct siginfo *info)
+{
+	fill_sigtrap_info(tsk, regs, 0, TRAP_BRKPT, info);
+}
 
+void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs,
+					 int error_code, int si_code)
+{
+	struct siginfo info;
+
+	fill_sigtrap_info(tsk, regs, error_code, si_code, &info);
 	/* Send us the fake SIGTRAP */
 	force_sig_info(SIGTRAP, &info, tsk);
 }
@@ -1755,29 +1767,22 @@ asmregparm long syscall_trace_enter(struct pt_regs *regs)
 
 asmregparm void syscall_trace_leave(struct pt_regs *regs)
 {
+	bool step;
+
 	if (unlikely(current->audit_context))
 		audit_syscall_exit(AUDITSC_RESULT(regs->ax), regs->ax);
 
 	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
 		trace_sys_exit(regs, regs->ax);
 
-	if (test_thread_flag(TIF_SYSCALL_TRACE))
-		tracehook_report_syscall_exit(regs, 0);
-
 	/*
 	 * If TIF_SYSCALL_EMU is set, we only get here because of
 	 * TIF_SINGLESTEP (i.e. this is PTRACE_SYSEMU_SINGLESTEP).
 	 * We already reported this syscall instruction in
-	 * syscall_trace_enter(), so don't do any more now.
-	 */
-	if (unlikely(test_thread_flag(TIF_SYSCALL_EMU)))
-		return;
-
-	/*
-	 * If we are single-stepping, synthesize a trap to follow the
-	 * system call instruction.
+	 * syscall_trace_enter().
 	 */
-	if (test_thread_flag(TIF_SINGLESTEP) &&
-	    tracehook_consider_fatal_signal(current, SIGTRAP))
-		send_sigtrap(current, regs, 0, TRAP_BRKPT);
+	step = unlikely(test_thread_flag(TIF_SINGLESTEP)) &&
+			!test_thread_flag(TIF_SYSCALL_EMU);
+	if (step || test_thread_flag(TIF_SYSCALL_TRACE))
+		tracehook_report_syscall_exit(regs, step);
 }