sparc: Prevent no-handler signal syscall restart recursion.

Explicitly clear the "in-syscall" bit when we have no signal
handler and back up the program counters to back up the system
call.

Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 7 insertions, 1 deletions

diff --git a/arch/sparc/kernel/signal32.c b/arch/sparc/kernel/signal32.c
index 643a354795cc..75fad425e249 100644
--- a/arch/sparc/kernel/signal32.c
+++ b/arch/sparc/kernel/signal32.c
@@ -616,7 +616,7 @@ static int setup_frame32(struct k_sigaction *ka, struct pt_regs *regs,
 
                 flush_signal_insns(address);
         }
-        return;
+        return 0;
 
 sigill:
         do_exit(SIGILL);
@@ -840,12 +840,14 @@ void do_signal32(sigset_t *oldset, struct pt_regs * regs,
                 regs->u_regs[UREG_I0] = orig_i0;
                 regs->tpc -= 4;
                 regs->tnpc -= 4;
+                pt_regs_clear_syscall(regs);
         }
         if (restart_syscall &&
             regs->u_regs[UREG_I0] == ERESTART_RESTARTBLOCK) {
                 regs->u_regs[UREG_G1] = __NR_restart_syscall;
                 regs->tpc -= 4;
                 regs->tnpc -= 4;
+                pt_regs_clear_syscall(regs);
         }
 
         /* If there's no signal to deliver, we just put the saved sigmask
diff --git a/arch/sparc/kernel/signal_32.c b/arch/sparc/kernel/signal_32.c
index 99c85e99bbcf..5e5c5fd03783 100644
--- a/arch/sparc/kernel/signal_32.c
+++ b/arch/sparc/kernel/signal_32.c
@@ -580,12 +580,14 @@ static void do_signal(struct pt_regs *regs, unsigned long orig_i0)
                 regs->u_regs[UREG_I0] = orig_i0;
                 regs->pc -= 4;
                 regs->npc -= 4;
+                pt_regs_clear_syscall(regs);
         }
         if (restart_syscall &&
             regs->u_regs[UREG_I0] == ERESTART_RESTARTBLOCK) {
                 regs->u_regs[UREG_G1] = __NR_restart_syscall;
                 regs->pc -= 4;
                 regs->npc -= 4;
+                pt_regs_clear_syscall(regs);
         }
 
         /* if there's no signal to deliver, we just put the saved sigmask
diff --git a/arch/sparc/kernel/signal_64.c b/arch/sparc/kernel/signal_64.c
index 3f19e673e2cd..006fe4515886 100644
--- a/arch/sparc/kernel/signal_64.c
+++ b/arch/sparc/kernel/signal_64.c
@@ -600,12 +600,14 @@ static void do_signal(struct pt_regs *regs, unsigned long orig_i0)
                 regs->u_regs[UREG_I0] = orig_i0;
                 regs->tpc -= 4;
                 regs->tnpc -= 4;
+                pt_regs_clear_syscall(regs);
         }
         if (restart_syscall &&
             regs->u_regs[UREG_I0] == ERESTART_RESTARTBLOCK) {
                 regs->u_regs[UREG_G1] = __NR_restart_syscall;
                 regs->tpc -= 4;
                 regs->tnpc -= 4;
+                pt_regs_clear_syscall(regs);
         }
 
         /* If there's no signal to deliver, we just put the saved sigmask