From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757527Ab0ITUtB (ORCPT ); Mon, 20 Sep 2010 16:49:01 -0400 Received: from zeniv.linux.org.uk ([195.92.253.2]:36092 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757388Ab0ITUtA (ORCPT ); Mon, 20 Sep 2010 16:49:00 -0400 Date: Mon, 20 Sep 2010 21:48:57 +0100 From: Al Viro To: linus-arch@ZenIV.linux.org.uk Cc: linux-kernel@vger.kernel.org, Benjamin Herrenschmidt , Paul Mackerras , Linus Torvalds Subject: powerpc: fix double syscall restarts Message-ID: <20100920204856.GF31363@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.20 (2009-08-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Make sigreturn zero regs->trap, make do_signal() do the same on all paths. As it is, signal interrupting e.g. read() from fd 512 (== ERESTARTSYS) with another signal getting unblocked when the first handler finishes will lead to restart one insn earlier than it ought to. Same for multiple signals with in-kernel handlers interrupting that sucker at the same time. Same for multiple signals of any kind interrupting that sucker on 64bit... Signed-off-by: Al Viro --- arch/powerpc/kernel/signal.c | 2 ++ arch/powerpc/kernel/signal_32.c | 3 +-- arch/powerpc/kernel/signal_64.c | 2 +- 3 files changed, 4 insertions(+), 3 deletions(-) diff --git a/arch/powerpc/kernel/signal.c b/arch/powerpc/kernel/signal.c index 7109f5b..2300426 100644 --- a/arch/powerpc/kernel/signal.c +++ b/arch/powerpc/kernel/signal.c @@ -138,6 +138,7 @@ static int do_signal_pending(sigset_t *oldset, struct pt_regs *regs) ti->local_flags &= ~_TLF_RESTORE_SIGMASK; sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL); } + regs->trap = 0; return 0; /* no signals delivered */ } @@ -164,6 +165,7 @@ static int do_signal_pending(sigset_t *oldset, struct pt_regs *regs) ret = handle_rt_signal64(signr, &ka, &info, oldset, regs); } + regs->trap = 0; if (ret) { spin_lock_irq(¤t->sighand->siglock); sigorsets(¤t->blocked, ¤t->blocked, diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c index 2666101..b96a3a0 100644 --- a/arch/powerpc/kernel/signal_32.c +++ b/arch/powerpc/kernel/signal_32.c @@ -511,6 +511,7 @@ static long restore_user_regs(struct pt_regs *regs, if (!sig) save_r2 = (unsigned int)regs->gpr[2]; err = restore_general_regs(regs, sr); + regs->trap = 0; err |= __get_user(msr, &sr->mc_gregs[PT_MSR]); if (!sig) regs->gpr[2] = (unsigned long) save_r2; @@ -884,7 +885,6 @@ int handle_rt_signal32(unsigned long sig, struct k_sigaction *ka, regs->nip = (unsigned long) ka->sa.sa_handler; /* enter the signal handler in big-endian mode */ regs->msr &= ~MSR_LE; - regs->trap = 0; return 1; badframe: @@ -1228,7 +1228,6 @@ int handle_signal32(unsigned long sig, struct k_sigaction *ka, regs->nip = (unsigned long) ka->sa.sa_handler; /* enter the signal handler in big-endian mode */ regs->msr &= ~MSR_LE; - regs->trap = 0; return 1; diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c index 2fe6fc6..27c4a45 100644 --- a/arch/powerpc/kernel/signal_64.c +++ b/arch/powerpc/kernel/signal_64.c @@ -178,7 +178,7 @@ static long restore_sigcontext(struct pt_regs *regs, sigset_t *set, int sig, err |= __get_user(regs->xer, &sc->gp_regs[PT_XER]); err |= __get_user(regs->ccr, &sc->gp_regs[PT_CCR]); /* skip SOFTE */ - err |= __get_user(regs->trap, &sc->gp_regs[PT_TRAP]); + regs->trap = 0; err |= __get_user(regs->dar, &sc->gp_regs[PT_DAR]); err |= __get_user(regs->dsisr, &sc->gp_regs[PT_DSISR]); err |= __get_user(regs->result, &sc->gp_regs[PT_RESULT]); -- 1.5.6.5