[PATCH] s390: rt_sigreturn fix

Check return code of do_sigaltstack and force a SIGSEGV if it is -EFAULT.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 3 insertions, 5 deletions

diff --git a/arch/s390/kernel/compat_signal.c b/arch/s390/kernel/compat_signal.c
index 4ff6808456ea..fa2b3bc22f20 100644
--- a/arch/s390/kernel/compat_signal.c
+++ b/arch/s390/kernel/compat_signal.c
@@ -467,8 +467,6 @@ asmlinkage long sys32_rt_sigreturn(struct pt_regs *regs)
         if (err)
                 goto badframe; 
 
-        /* It is more difficult to avoid calling this function than to
-           call it and ignore errors.  */
         set_fs (KERNEL_DS);
         do_sigaltstack((stack_t __user *)&st, NULL, regs->gprs[15]);
         set_fs (old_fs);
diff --git a/arch/s390/kernel/signal.c b/arch/s390/kernel/signal.c
index 6e0110d71191..13592d00a10f 100644
--- a/arch/s390/kernel/signal.c
+++ b/arch/s390/kernel/signal.c
@@ -254,9 +254,9 @@ asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
         if (restore_sigregs(regs, &frame->uc.uc_mcontext))
                 goto badframe;
 
-        /* It is more difficult to avoid calling this function than to
-           call it and ignore errors.  */
-        do_sigaltstack(&frame->uc.uc_stack, NULL, regs->gprs[15]);
+        if (do_sigaltstack(&frame->uc.uc_stack, NULL,
+                           regs->gprs[15]) == -EFAULT)
+                goto badframe;
         return regs->gprs[2];
 
 badframe: