Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm…

…/linux/kernel/git/tip/tip

Pull rseq fixes from Thomas Gleixer:
 "A pile of rseq related fixups:

   - Prevent infinite recursion when delivering SIGSEGV

   - Remove the abort of rseq critical section on fork() as syscalls
     inside rseq critical sections are explicitely forbidden. So no
     point in doing the abort on the child.

   - Align the rseq structure on 32 bytes in the ARM selftest code.

   - Fix file permissions of the test script"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  rseq: Avoid infinite recursion when delivering SIGSEGV
  rseq/cleanup: Do not abort rseq c.s. in child on fork()
  rseq/selftests/arm: Align 'struct rseq_cs' on 32 bytes
  rseq/selftests: Make run_param_test.sh executable

arch/arm/kernel/signal.c

@@ -544,7 +544,7 @@ static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
 	 * Increment event counter and perform fixup for the pre-signal
 	 * frame.
 	 */
-	rseq_signal_deliver(regs);
+	rseq_signal_deliver(ksig, regs);
 
 	/*
 	 * Set up the stack frame
@@ -666,7 +666,7 @@ do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall)
 			} else {
 				clear_thread_flag(TIF_NOTIFY_RESUME);
 				tracehook_notify_resume(regs);
-				rseq_handle_notify_resume(regs);
+				rseq_handle_notify_resume(NULL, regs);
 			}
 		}
 		local_irq_disable();

arch/powerpc/kernel/signal.c

@@ -134,7 +134,7 @@ static void do_signal(struct task_struct *tsk)
 	/* Re-enable the breakpoints for the signal stack */
 	thread_change_pc(tsk, tsk->thread.regs);
 
-	rseq_signal_deliver(tsk->thread.regs);
+	rseq_signal_deliver(&ksig, tsk->thread.regs);
 
 	if (is32) {
         	if (ksig.ka.sa.sa_flags & SA_SIGINFO)
@@ -170,7 +170,7 @@ void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags)
 	if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 		clear_thread_flag(TIF_NOTIFY_RESUME);
 		tracehook_notify_resume(regs);
-		rseq_handle_notify_resume(regs);
+		rseq_handle_notify_resume(NULL, regs);
 	}
 
 	user_enter();

arch/x86/entry/common.c

@@ -164,7 +164,7 @@ static void exit_to_usermode_loop(struct pt_regs *regs, u32 cached_flags)
 		if (cached_flags & _TIF_NOTIFY_RESUME) {
 			clear_thread_flag(TIF_NOTIFY_RESUME);
 			tracehook_notify_resume(regs);
-			rseq_handle_notify_resume(regs);
+			rseq_handle_notify_resume(NULL, regs);
 		}
 
 		if (cached_flags & _TIF_USER_RETURN_NOTIFY)

arch/x86/kernel/signal.c

@@ -692,7 +692,7 @@ setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs)
 	 * Increment event counter and perform fixup for the pre-signal
 	 * frame.
 	 */
-	rseq_signal_deliver(regs);
+	rseq_signal_deliver(ksig, regs);
 
 	/* Set up the stack frame */
 	if (is_ia32_frame(ksig)) {

include/linux/sched.h

@@ -1799,20 +1799,22 @@ static inline void rseq_set_notify_resume(struct task_struct *t)
 		set_tsk_thread_flag(t, TIF_NOTIFY_RESUME);
 }
 
-void __rseq_handle_notify_resume(struct pt_regs *regs);
+void __rseq_handle_notify_resume(struct ksignal *sig, struct pt_regs *regs);
 
-static inline void rseq_handle_notify_resume(struct pt_regs *regs)
+static inline void rseq_handle_notify_resume(struct ksignal *ksig,
+					     struct pt_regs *regs)
 {
 	if (current->rseq)
-		__rseq_handle_notify_resume(regs);
+		__rseq_handle_notify_resume(ksig, regs);
 }
 
-static inline void rseq_signal_deliver(struct pt_regs *regs)
+static inline void rseq_signal_deliver(struct ksignal *ksig,
+				       struct pt_regs *regs)
 {
 	preempt_disable();
 	__set_bit(RSEQ_EVENT_SIGNAL_BIT, &current->rseq_event_mask);
 	preempt_enable();
-	rseq_handle_notify_resume(regs);
+	rseq_handle_notify_resume(ksig, regs);
 }
 
 /* rseq_preempt() requires preemption to be disabled. */
@@ -1831,9 +1833,7 @@ static inline void rseq_migrate(struct task_struct *t)
 
 /*
  * If parent process has a registered restartable sequences area, the
- * child inherits. Only applies when forking a process, not a thread. In
- * case a parent fork() in the middle of a restartable sequence, set the
- * resume notifier to force the child to retry.
+ * child inherits. Only applies when forking a process, not a thread.
  */
 static inline void rseq_fork(struct task_struct *t, unsigned long clone_flags)
 {
@@ -1847,7 +1847,6 @@ static inline void rseq_fork(struct task_struct *t, unsigned long clone_flags)
 		t->rseq_len = current->rseq_len;
 		t->rseq_sig = current->rseq_sig;
 		t->rseq_event_mask = current->rseq_event_mask;
-		rseq_preempt(t);
 	}
 }
 
@@ -1864,10 +1863,12 @@ static inline void rseq_execve(struct task_struct *t)
 static inline void rseq_set_notify_resume(struct task_struct *t)
 {
 }
-static inline void rseq_handle_notify_resume(struct pt_regs *regs)
+static inline void rseq_handle_notify_resume(struct ksignal *ksig,
+					     struct pt_regs *regs)
 {
 }
-static inline void rseq_signal_deliver(struct pt_regs *regs)
+static inline void rseq_signal_deliver(struct ksignal *ksig,
+				       struct pt_regs *regs)
 {
 }
 static inline void rseq_preempt(struct task_struct *t)

kernel/rseq.c

@@ -251,10 +251,10 @@ static int rseq_ip_fixup(struct pt_regs *regs)
  * respect to other threads scheduled on the same CPU, and with respect
  * to signal handlers.
  */
-void __rseq_handle_notify_resume(struct pt_regs *regs)
+void __rseq_handle_notify_resume(struct ksignal *ksig, struct pt_regs *regs)
 {
 	struct task_struct *t = current;
-	int ret;
+	int ret, sig;
 
 	if (unlikely(t->flags & PF_EXITING))
 		return;
@@ -268,7 +268,8 @@ void __rseq_handle_notify_resume(struct pt_regs *regs)
 	return;
 
 error:
-	force_sig(SIGSEGV, t);
+	sig = ksig ? ksig->sig : 0;
+	force_sigsegv(sig, t);
 }
 
 #ifdef CONFIG_DEBUG_RSEQ

tools/testing/selftests/rseq/rseq-arm.h

@@ -57,6 +57,7 @@ do {									\
 #define __RSEQ_ASM_DEFINE_ABORT(table_label, label, teardown,		\
 				abort_label, version, flags,		\
 				start_ip, post_commit_offset, abort_ip)	\
+		".balign 32\n\t"					\
 		__rseq_str(table_label) ":\n\t"				\
 		".word " __rseq_str(version) ", " __rseq_str(flags) "\n\t" \
 		".word " __rseq_str(start_ip) ", 0x0, " __rseq_str(post_commit_offset) ", 0x0, " __rseq_str(abort_ip) ", 0x0\n\t" \