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

8 files changed, 23 insertions, 20 deletions

diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c
index f09e9d66d605..dec130e7078c 100644
--- a/arch/arm/kernel/signal.c
+++ b/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();
diff --git a/arch/powerpc/kernel/signal.c b/arch/powerpc/kernel/signal.c
index 17fe4339ba59..b3e8db376ecd 100644
--- a/arch/powerpc/kernel/signal.c
+++ b/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();
diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index 92190879b228..3b2490b81918 100644
--- a/arch/x86/entry/common.c
+++ b/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)
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index 445ca11ff863..92a3b312a53c 100644
--- a/arch/x86/kernel/signal.c
+++ b/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)) {
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 87bf02d93a27..9256118bd40c 100644
--- a/include/linux/sched.h
+++ b/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)
diff --git a/kernel/rseq.c b/kernel/rseq.c
index ae306f90c514..22b6acf1ad63 100644
--- a/kernel/rseq.c
+++ b/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
diff --git a/tools/testing/selftests/rseq/rseq-arm.h b/tools/testing/selftests/rseq/rseq-arm.h
index 3b055f9aeaab..3cea19877227 100644
--- a/tools/testing/selftests/rseq/rseq-arm.h
+++ b/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" \
diff --git a/tools/testing/selftests/rseq/run_param_test.sh b/tools/testing/selftests/rseq/run_param_test.sh
index 3acd6d75ff9f..3acd6d75ff9f 100644..100755
--- a/tools/testing/selftests/rseq/run_param_test.sh
+++ b/tools/testing/selftests/rseq/run_param_test.sh