Merge branch 'for-curr' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc

Pull ARC fix from Vineet Gupta:
 "Chrisitian found/fixed issue with SA_SIGINFO based signal handler
  corrupting the user space registers post after signal handling"

* 'for-curr' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc:
  ARC: Fix signal frame management for SA_SIGINFO

1 files changed, 13 insertions, 12 deletions

diff --git a/arch/arc/kernel/signal.c b/arch/arc/kernel/signal.c
index ee6ef2f60a28..7e95e1a86510 100644
--- a/arch/arc/kernel/signal.c
+++ b/arch/arc/kernel/signal.c
@@ -101,7 +101,6 @@ SYSCALL_DEFINE0(rt_sigreturn)
 {
         struct rt_sigframe __user *sf;
         unsigned int magic;
-        int err;
         struct pt_regs *regs = current_pt_regs();
 
         /* Always make any pending restarted system calls return -EINTR */
@@ -119,15 +118,16 @@ SYSCALL_DEFINE0(rt_sigreturn)
         if (!access_ok(VERIFY_READ, sf, sizeof(*sf)))
                 goto badframe;
 
-        err = restore_usr_regs(regs, sf);
-        err |= __get_user(magic, &sf->sigret_magic);
-        if (err)
+        if (__get_user(magic, &sf->sigret_magic))
                 goto badframe;
 
         if (unlikely(is_do_ss_needed(magic)))
                 if (restore_altstack(&sf->uc.uc_stack))
                         goto badframe;
 
+        if (restore_usr_regs(regs, sf))
+                goto badframe;
+
         /* Don't restart from sigreturn */
         syscall_wont_restart(regs);
 
@@ -191,6 +191,15 @@ setup_rt_frame(int signo, struct k_sigaction *ka, siginfo_t *info,
                 return 1;
 
         /*
+         * w/o SA_SIGINFO, struct ucontext is partially populated (only
+         * uc_mcontext/uc_sigmask) for kernel's normal user state preservation
+         * during signal handler execution. This works for SA_SIGINFO as well
+         * although the semantics are now overloaded (the same reg state can be
+         * inspected by userland: but are they allowed to fiddle with it ?
+         */
+        err |= stash_usr_regs(sf, regs, set);
+
+        /*
          * SA_SIGINFO requires 3 args to signal handler:
          *  #1: sig-no (common to any handler)
          *  #2: struct siginfo
@@ -213,14 +222,6 @@ setup_rt_frame(int signo, struct k_sigaction *ka, siginfo_t *info,
                 magic = MAGIC_SIGALTSTK;
         }
 
-        /*
-         * w/o SA_SIGINFO, struct ucontext is partially populated (only
-         * uc_mcontext/uc_sigmask) for kernel's normal user state preservation
-         * during signal handler execution. This works for SA_SIGINFO as well
-         * although the semantics are now overloaded (the same reg state can be
-         * inspected by userland: but are they allowed to fiddle with it ?
-         */
-        err |= stash_usr_regs(sf, regs, set);
         err |= __put_user(magic, &sf->sigret_magic);
         if (err)
                 return err;