From patchwork Tue Nov 18 23:09:47 2008 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeremy Kerr X-Patchwork-Id: 9510 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from ozlabs.org (localhost [127.0.0.1]) by ozlabs.org (Postfix) with ESMTP id 16C8847689 for ; Wed, 19 Nov 2008 10:10:10 +1100 (EST) X-Original-To: cbe-oss-dev@ozlabs.org Delivered-To: cbe-oss-dev@ozlabs.org Received: by ozlabs.org (Postfix, from userid 1023) id 7EEE3DDE0A; Wed, 19 Nov 2008 10:09:56 +1100 (EST) MIME-Version: 1.0 Message-Id: <1227049787.482219.695250894439.1.gpush@pingu> To: From: Jeremy Kerr Date: Wed, 19 Nov 2008 10:09:47 +1100 Subject: [Cbe-oss-dev] [PATCH] powerpc/spufs: Fix spinning in spufs_ps_fault on signal X-BeenThere: cbe-oss-dev@ozlabs.org X-Mailman-Version: 2.1.11 Precedence: list List-Id: Discussion about Open Source Software for the Cell Broadband Engine List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: cbe-oss-dev-bounces+patchwork-incoming=ozlabs.org@ozlabs.org Errors-To: cbe-oss-dev-bounces+patchwork-incoming=ozlabs.org@ozlabs.org Currently, we can end up in an infinite loop if we get a signal while the kernel has faulted in spufs_ps_fault. Eg: alarm(1); write(fd, some_spu_psmap_register_address, 4); - the write's copy_from_user will fault on the ps mapping, and signal_pending will be non-zero. Because returning from the fault handler will never clear TIF_SIGPENDING, so we'll just keep faulting, resulting in an unkillable process using 100% of CPU. This change returns VM_FAULT_SIGBUS if there's a fatal signal pending, letting us escape the loop. Signed-off-by: Jeremy Kerr --- arch/powerpc/platforms/cell/spufs/file.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/powerpc/platforms/cell/spufs/file.c b/arch/powerpc/platforms/cell/spufs/file.c index b73c369..1b26071 100644 --- a/arch/powerpc/platforms/cell/spufs/file.c +++ b/arch/powerpc/platforms/cell/spufs/file.c @@ -390,6 +390,9 @@ static int spufs_ps_fault(struct vm_area_struct *vma, if (offset >= ps_size) return VM_FAULT_SIGBUS; + if (fatal_signal_pending(current)) + return VM_FAULT_SIGBUS; + /* * Because we release the mmap_sem, the context may be destroyed while * we're in spu_wait. Grab an extra reference so it isn't destroyed