Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752104AbdITVDI (ORCPT ); Wed, 20 Sep 2017 17:03:08 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:52346 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751716AbdITVDD (ORCPT ); Wed, 20 Sep 2017 17:03:03 -0400 From: Tyrel Datwyler To: mpe@ellerman.id.au Cc: linuxppc-dev@lists.ozlabs.org, robh+dt@kernel.org, abdhalee@linux.vnet.ibm.com, paulus@samba.org, sachinp@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, Tyrel Datwyler , stable@vger.kernel.org, #@b01ledav001.gho.pok.ibm.com, v4.13+@b01ledav001.gho.pok.ibm.com Subject: [PATCH 1/2] powerpc/pseries: fix "OF: ERROR: Bad of_node_put() on /cpus" during DLPAR Date: Wed, 20 Sep 2017 17:02:51 -0400 X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1505473476.9665.13.camel@abdul.in.ibm.com> References: <1505473476.9665.13.camel@abdul.in.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 17092021-2213-0000-0000-0000021E7ADF X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00007769; HX=3.00000241; KW=3.00000007; PH=3.00000004; SC=3.00000230; SDB=6.00919915; UDB=6.00462199; IPR=6.00700141; BA=6.00005599; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00017225; XFM=3.00000015; UTC=2017-09-20 21:03:00 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17092021-2214-0000-0000-0000579C6BD5 Message-Id: <1505941372-9147-1-git-send-email-tyreld@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-09-20_05:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=1 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1707230000 definitions=main-1709200281 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3698 Lines: 84 Commit 215ee763f8cb ("powerpc: pseries: remove dlpar_attach_node dependency on full path") reworked dlpar_attach_node() to no longer look up the parent node "/cpus", but instead to have the parent node passed by the caller in the function parameter list. As a result dlpar_attach_node() is no longer responsible for freeing the reference to the parent node. However, commit 215ee763f8cb failed to remove the of_node_put(parent) call in dlpar_attach_node(), or to take into account that the reference to the parent in the caller dlpar_cpu_add() needs to be held until after dlpar_attach_node() returns. As a result doing repeated cpu add/remove dlpar operations will eventually result in the following error: OF: ERROR: Bad of_node_put() on /cpus CPU: 0 PID: 10896 Comm: drmgr Not tainted 4.13.0-autotest #1 Call Trace: [c00000026ecdf810] [c00000000278a2a4] dump_stack+0x15c/0x1f8 (unreliable) [c00000026ecdf850] [c0000000025371a4] of_node_release+0x1a4/0x1c0 [c00000026ecdf8e0] [c0000000027948c8] kobject_put+0x1a8/0x310 [c00000026ecdf960] [c000000002794bdc] kobject_del+0xbc/0xf0 [c00000026ecdf990] [c000000002535ff4] __of_detach_node_sysfs+0x144/0x210 [c00000026ecdf9d0] [c000000002536f70] of_detach_node+0xf0/0x180 [c00000026ecdfa40] [c0000000016ed494] dlpar_detach_node+0xc4/0x120 [c00000026ecdfa80] [c0000000016f47d0] dlpar_cpu_remove+0x280/0x560 [c00000026ecdfb60] [c0000000016f4d9c] dlpar_cpu_release+0xbc/0x1b0 [c00000026ecdfbb0] [c00000000161279c] arch_cpu_release+0x6c/0xb0 [c00000026ecdfbe0] [c00000000218ebf0] cpu_release_store+0xa0/0x100 [c00000026ecdfc20] [c000000002178388] dev_attr_store+0x68/0xa0 [c00000026ecdfc50] [c000000001bfaae8] sysfs_kf_write+0xa8/0xf0 [c00000026ecdfc80] [c000000001bf8a3c] kernfs_fop_write+0x2cc/0x400 [c00000026ecdfce0] [c000000001ad33fc] __vfs_write+0x5c/0x340 [c00000026ecdfd80] [c000000001ad89e8] vfs_write+0x1a8/0x3d0 [c00000026ecdfdd0] [c000000001ad9178] SyS_write+0xa8/0x1a0 [c00000026ecdfe30] [c0000000015eb8e0] system_call+0x58/0x6c Fix the issue by removing the of_node_put(parent) call from dlpar_attach_node(), and ensuring that the reference to the parent node is properly held and released by the caller dlpar_cpu_add(). Cc: stable@vger.kernel.org # v4.13+ Fixes: 215ee763f8cb ("powerpc: pseries: remove dlpar_attach_node dependency on full path") Signed-off-by: Tyrel Datwyler Reported-by: Abdul Haleem --- arch/powerpc/platforms/pseries/dlpar.c | 1 - arch/powerpc/platforms/pseries/hotplug-cpu.c | 4 +++- 2 files changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/platforms/pseries/dlpar.c b/arch/powerpc/platforms/pseries/dlpar.c index 783f363..e45b5f1 100644 --- a/arch/powerpc/platforms/pseries/dlpar.c +++ b/arch/powerpc/platforms/pseries/dlpar.c @@ -266,7 +266,6 @@ int dlpar_attach_node(struct device_node *dn, struct device_node *parent) return rc; } - of_node_put(dn->parent); return 0; } diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c index fc0d8f9..473d817 100644 --- a/arch/powerpc/platforms/pseries/hotplug-cpu.c +++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c @@ -462,15 +462,17 @@ static ssize_t dlpar_cpu_add(u32 drc_index) } dn = dlpar_configure_connector(cpu_to_be32(drc_index), parent); - of_node_put(parent); if (!dn) { pr_warn("Failed call to configure-connector, drc index: %x\n", drc_index); dlpar_release_drc(drc_index); + of_node_put(parent); return -EINVAL; } rc = dlpar_attach_node(dn, parent); + of_node_put(parent); + if (rc) { saved_rc = rc; pr_warn("Failed to attach node %s, rc: %d, drc index: %x\n", -- 1.8.3.1