From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:46921 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755086AbbGaUDE (ORCPT ); Fri, 31 Jul 2015 16:03:04 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, John Stultz , Nicolas Pitre , Steven Rostedt , "Paul E. McKenney" , Stephen Boyd , Catalin Marinas Subject: [PATCH 4.1 258/267] ARM64: smp: Fix suspicious RCU usage with ipi tracepoints Date: Fri, 31 Jul 2015 12:41:49 -0700 Message-Id: <20150731194011.759784356@linuxfoundation.org> In-Reply-To: <20150731194001.933895871@linuxfoundation.org> References: <20150731194001.933895871@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Stephen Boyd commit be081d9bf3e163a9ed1ca2f0f14f08424c7f9016 upstream. John Stultz reported an RCU splat on ARM with ipi trace events enabled. It looks like the same problem exists on ARM64. At this point in the IPI handling path we haven't called irq_enter() yet, so RCU doesn't know that we're about to exit idle and properly warns that we're using RCU from an idle CPU. Use trace_ipi_entry_rcuidle() instead of trace_ipi_entry() so that RCU is informed about our exit from idle. Cc: John Stultz Cc: Nicolas Pitre Acked-by: Steven Rostedt Reviewed-by: Paul E. McKenney Fixes: 45ed695ac10a ("ARM64: add IPI tracepoints") Signed-off-by: Stephen Boyd Signed-off-by: Catalin Marinas Signed-off-by: Greg Kroah-Hartman --- arch/arm64/kernel/smp.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -569,7 +569,7 @@ void handle_IPI(int ipinr, struct pt_reg struct pt_regs *old_regs = set_irq_regs(regs); if ((unsigned)ipinr < NR_IPI) { - trace_ipi_entry(ipi_types[ipinr]); + trace_ipi_entry_rcuidle(ipi_types[ipinr]); __inc_irq_stat(cpu, ipi_irqs[ipinr]); } @@ -612,7 +612,7 @@ void handle_IPI(int ipinr, struct pt_reg } if ((unsigned)ipinr < NR_IPI) - trace_ipi_exit(ipi_types[ipinr]); + trace_ipi_exit_rcuidle(ipi_types[ipinr]); set_irq_regs(old_regs); }