Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757460Ab2EHXPE (ORCPT ); Tue, 8 May 2012 19:15:04 -0400 Received: from mga02.intel.com ([134.134.136.20]:47432 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754011Ab2EHXPC (ORCPT ); Tue, 8 May 2012 19:15:02 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.67,352,1309762800"; d="scan'208";a="138405377" From: Suresh Siddha To: torvalds@linux-foundation.org, hpa@zytor.com, mingo@elte.hu, oleg@redhat.com Cc: Suresh Siddha , linux-kernel@vger.kernel.org, suresh@aristanetworks.com Subject: [PATCH 2/3] x86, xsave: remove thread_has_fpu() bug check in __sanitize_i387_state() Date: Tue, 8 May 2012 16:18:04 -0700 Message-Id: <1336519085-27450-3-git-send-email-suresh.b.siddha@intel.com> X-Mailer: git-send-email 1.7.6.5 In-Reply-To: <1336519085-27450-1-git-send-email-suresh.b.siddha@intel.com> References: <1336421341.19423.4.camel@sbsiddha-desk.sc.intel.com> <1336519085-27450-1-git-send-email-suresh.b.siddha@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1368 Lines: 40 Code paths like fork(), exit() and signal handling flush the fpu state explicitly to the structures in memory. BUG_ON() in __sanitize_i387_state() is checking that the fpu state is not live any more. But for preempt kernels, task can be scheduled out and in at any place and the preload_fpu logic during context switch can make the fpu registers live again. Similarly during core dump, thread dumping the core can schedule out and in for page-allocations etc in non-preempt case. So remove the paranoid check, even though it caught a bug in the multi-threaded core dump case (fixed in the previous patch). Signed-off-by: Suresh Siddha --- arch/x86/kernel/xsave.c | 2 -- 1 files changed, 0 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/xsave.c b/arch/x86/kernel/xsave.c index e62728e..bd18149 100644 --- a/arch/x86/kernel/xsave.c +++ b/arch/x86/kernel/xsave.c @@ -48,8 +48,6 @@ void __sanitize_i387_state(struct task_struct *tsk) if (!fx) return; - BUG_ON(__thread_has_fpu(tsk)); - xstate_bv = tsk->thread.fpu.state->xsave.xsave_hdr.xstate_bv; /* -- 1.7.6.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/