Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751858AbdIVBDg (ORCPT ); Thu, 21 Sep 2017 21:03:36 -0400 Received: from ozlabs.org ([103.22.144.67]:41257 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751785AbdIVBDf (ORCPT ); Thu, 21 Sep 2017 21:03:35 -0400 X-powerpc-patch-notification: thanks X-powerpc-patch-commit: 087ff6a5ae3052bb2835e191094b793789cb8817 In-Reply-To: <1505941372-9147-1-git-send-email-tyreld@linux.vnet.ibm.com> To: Tyrel Datwyler From: Michael Ellerman Cc: sachinp@linux.vnet.ibm.com, v4.13+@b01ledav001.gho.pok.ibm.com, linux-kernel@vger.kernel.org, stable@vger.kernel.org, abdhalee@linux.vnet.ibm.com, robh+dt@kernel.org, paulus@samba.org, Tyrel Datwyler , #@b01ledav001.gho.pok.ibm.com, linuxppc-dev@lists.ozlabs.org Subject: Re: [1/2] powerpc/pseries: fix "OF: ERROR: Bad of_node_put() on /cpus" during DLPAR Message-Id: <3xywGF3LZvz9t32@ozlabs.org> Date: Fri, 22 Sep 2017 11:03:33 +1000 (AEST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2678 Lines: 49 On Wed, 2017-09-20 at 21:02:51 UTC, Tyrel Datwyler wrote: > 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 Series applied to powerpc fixes, thanks. https://git.kernel.org/powerpc/c/087ff6a5ae3052bb2835e191094b79 cheers