From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:53652 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966025AbeEXJlx (ORCPT ); Thu, 24 May 2018 05:41:53 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Nicholas Piggin , Michael Ellerman Subject: [PATCH 3.18 33/45] powerpc/powernv: Fix NVRAM sleep in invalid context when crashing Date: Thu, 24 May 2018 11:38:41 +0200 Message-Id: <20180524093124.842743719@linuxfoundation.org> In-Reply-To: <20180524093120.599252450@linuxfoundation.org> References: <20180524093120.599252450@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Nicholas Piggin commit c1d2a31397ec51f0370f6bd17b19b39152c263cb upstream. Similarly to opal_event_shutdown, opal_nvram_write can be called in the crash path with irqs disabled. Special case the delay to avoid sleeping in invalid context. Fixes: 3b8070335f75 ("powerpc/powernv: Fix OPAL NVRAM driver OPAL_BUSY loops") Cc: stable@vger.kernel.org # v3.2 Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman --- arch/powerpc/platforms/powernv/opal-nvram.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) --- a/arch/powerpc/platforms/powernv/opal-nvram.c +++ b/arch/powerpc/platforms/powernv/opal-nvram.c @@ -43,6 +43,10 @@ static ssize_t opal_nvram_read(char *buf return count; } +/* + * This can be called in the panic path with interrupts off, so use + * mdelay in that case. + */ static ssize_t opal_nvram_write(char *buf, size_t count, loff_t *index) { s64 rc = OPAL_BUSY; @@ -57,10 +61,16 @@ static ssize_t opal_nvram_write(char *bu while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) { rc = opal_write_nvram(__pa(buf), count, off); if (rc == OPAL_BUSY_EVENT) { - msleep(OPAL_BUSY_DELAY_MS); + if (in_interrupt() || irqs_disabled()) + mdelay(OPAL_BUSY_DELAY_MS); + else + msleep(OPAL_BUSY_DELAY_MS); opal_poll_events(NULL); } else if (rc == OPAL_BUSY) { - msleep(OPAL_BUSY_DELAY_MS); + if (in_interrupt() || irqs_disabled()) + mdelay(OPAL_BUSY_DELAY_MS); + else + msleep(OPAL_BUSY_DELAY_MS); } }