From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , alan@lxorguk.ukuu.org.uk, Al Viro , "David S. Miller" Subject: [ 22/37] sparc64: not any error from do_sigaltstack() should fail rt_sigreturn() Date: Fri, 30 Nov 2012 10:46:09 -0800 Message-Id: <20121130183859.634524718@linuxfoundation.org> In-Reply-To: <20121130183857.166228045@linuxfoundation.org> References: <20121130183857.166228045@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Al Viro commit fae2ae2a900a5c7bb385fe4075f343e7e2d5daa2 upstream. If a signal handler is executed on altstack and another signal comes, we will end up with rt_sigreturn() on return from the second handler getting -EPERM from do_sigaltstack(). It's perfectly OK, since we are not asking to change the settings; in fact, they couldn't have been changed during the second handler execution exactly because we'd been on altstack all along. 64bit sigreturn on sparc treats any error from do_sigaltstack() as "SIGSEGV now"; we need to switch to the same semantics we are using on other architectures. Signed-off-by: Al Viro Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- arch/sparc/kernel/signal_64.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) --- a/arch/sparc/kernel/signal_64.c +++ b/arch/sparc/kernel/signal_64.c @@ -309,9 +309,7 @@ void do_rt_sigreturn(struct pt_regs *reg err |= restore_fpu_state(regs, fpu_save); err |= __copy_from_user(&set, &sf->mask, sizeof(sigset_t)); - err |= do_sigaltstack(&sf->stack, NULL, (unsigned long)sf); - - if (err) + if (err || do_sigaltstack(&sf->stack, NULL, (unsigned long)sf) == -EFAULT) goto segv; err |= __get_user(rwin_save, &sf->rwin_save);