m68k: If we fail to set sigframe up, just leave regs alone...

Same principle as with the previous patch - do not destroy the
state if sigframe setup fails.  Incidentally, it's actually
_less_ work - we don't need to go through adjust_stack dance
on failure if we don't touch regs->stkadj until we know we'd
written sigframe out.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>

diff --git a/arch/m68k/kernel/signal.c b/arch/m68k/kernel/signal.c
index a6dd61418e76bc49a6b60efd1c93484025c0fb20..16ea319d1ed53a134a93dd8f35dfb21f29a304f2 100644 (file)
--- a/arch/m68k/kernel/signal.c
+++ b/arch/m68k/kernel/signal.c
@@ -761,10 +761,8 @@ static int setup_frame (int sig, struct k_sigaction *ka,
 
        frame = get_sigframe(ka, regs, sizeof(*frame) + fsize);
 
-       if (fsize) {
+       if (fsize)
                err |= copy_to_user (frame + 1, regs + 1, fsize);
-               regs->stkadj = fsize;
-       }
 
        err |= __put_user((current_thread_info()->exec_domain
                           && current_thread_info()->exec_domain->signal_invmap
@@ -794,11 +792,21 @@ static int setup_frame (int sig, struct k_sigaction *ka,
 
        push_cache ((unsigned long) &frame->retcode);
 
-       /* Set up registers for signal handler */
+       /*
+        * Set up registers for signal handler.  All the state we are about
+        * to destroy is successfully copied to sigframe.
+        */
        wrusp ((unsigned long) frame);
        regs->pc = (unsigned long) ka->sa.sa_handler;
 
-adjust_stack:
+       /*
+        * This is subtle; if we build more than one sigframe, all but the
+        * first one will see frame format 0 and have fsize == 0, so we won't
+        * screw stkadj.
+        */
+       if (fsize)
+               regs->stkadj = fsize;
+
        /* Prepare to skip over the extra stuff in the exception frame.  */
        if (regs->stkadj) {
                struct pt_regs *tregs =
@@ -813,11 +821,11 @@ adjust_stack:
                tregs->pc = regs->pc;
                tregs->sr = regs->sr;
        }
-       return err;
+       return 0;
 
 give_sigsegv:
        force_sigsegv(sig, current);
-       goto adjust_stack;
+       return err;
 }
 
 static int setup_rt_frame (int sig, struct k_sigaction *ka, siginfo_t *info,
@@ -837,10 +845,8 @@ static int setup_rt_frame (int sig, struct k_sigaction *ka, siginfo_t *info,
 
        frame = get_sigframe(ka, regs, sizeof(*frame));
 
-       if (fsize) {
+       if (fsize)
                err |= copy_to_user (&frame->uc.uc_extra, regs + 1, fsize);
-               regs->stkadj = fsize;
-       }
 
        err |= __put_user((current_thread_info()->exec_domain
                           && current_thread_info()->exec_domain->signal_invmap
@@ -882,11 +888,21 @@ static int setup_rt_frame (int sig, struct k_sigaction *ka, siginfo_t *info,
 
        push_cache ((unsigned long) &frame->retcode);
 
-       /* Set up registers for signal handler */
+       /*
+        * Set up registers for signal handler.  All the state we are about
+        * to destroy is successfully copied to sigframe.
+        */
        wrusp ((unsigned long) frame);
        regs->pc = (unsigned long) ka->sa.sa_handler;
 
-adjust_stack:
+       /*
+        * This is subtle; if we build more than one sigframe, all but the
+        * first one will see frame format 0 and have fsize == 0, so we won't
+        * screw stkadj.
+        */
+       if (fsize)
+               regs->stkadj = fsize;
+
        /* Prepare to skip over the extra stuff in the exception frame.  */
        if (regs->stkadj) {
                struct pt_regs *tregs =
@@ -901,11 +917,11 @@ adjust_stack:
                tregs->pc = regs->pc;
                tregs->sr = regs->sr;
        }
-       return err;
+       return 0;
 
 give_sigsegv:
        force_sigsegv(sig, current);
-       goto adjust_stack;
+       return err;
 }
 
 static inline void