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Violators will be prosecuted for from ; Tue, 2 Oct 2018 10:18:30 -0400 Subject: Re: FAILED: patch "[PATCH] powerpc/pseries: Fix unitialized timer reset on migration" failed to apply to 4.4-stable tree To: gregkh@linuxfoundation.org, mpe@ellerman.id.au Cc: stable@vger.kernel.org References: <153848271313943@kroah.com> From: Michael Bringmann Date: Tue, 2 Oct 2018 09:18:26 -0500 MIME-Version: 1.0 In-Reply-To: <153848271313943@kroah.com> Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: 7bit Message-Id: <10de1312-353a-2c0e-ab00-6a4e037a5fae@linux.vnet.ibm.com> Sender: stable-owner@vger.kernel.org List-ID: To backport the patc commit 8604895a34d92f5e186ceb931b0d1b384030ea3d to the 4.4-stable tree, please try the following backport: diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c --- a/arch/powerpc/mm/numa.c 2018-10-02 09:03:06.232491410 -0500 +++ b/arch/powerpc/mm/numa.c 2018-10-02 09:04:17.152494472 -0500 @@ -1606,7 +1606,8 @@ { topology_timer.data = 0; topology_timer.expires = jiffies + topology_timer_secs * HZ; - mod_timer(&topology_timer, topology_timer.expires); + if (vphn_enabled) + mod_timer(&topology_timer, topology_timer.expires); } #ifdef CONFIG_SMP On 10/02/2018 07:18 AM, gregkh@linuxfoundation.org wrote: > > The patch below does not apply to the 4.4-stable tree. > If someone wants it applied there, or to any other stable or longterm > tree, then please email the backport, including the original git commit > id to . > > thanks, > > greg k-h > > ------------------ original commit in Linus's tree ------------------ > >>>>From 8604895a34d92f5e186ceb931b0d1b384030ea3d Mon Sep 17 00:00:00 2001 > From: Michael Bringmann > Date: Thu, 20 Sep 2018 11:45:13 -0500 > Subject: [PATCH] powerpc/pseries: Fix unitialized timer reset on migration > > After migration of a powerpc LPAR, the kernel executes code to > update the system state to reflect new platform characteristics. > > Such changes include modifications to device tree properties provided > to the system by PHYP. Property notifications received by the > post_mobility_fixup() code are passed along to the kernel in general > through a call to of_update_property() which in turn passes such > events back to all modules through entries like the '.notifier_call' > function within the NUMA module. > > When the NUMA module updates its state, it resets its event timer. If > this occurs after a previous call to stop_topology_update() or on a > system without VPHN enabled, the code runs into an unitialized timer > structure and crashes. This patch adds a safety check along this path > toward the problem code. > > An example crash log is as follows. > > ibmvscsi 30000081: Re-enabling adapter! > ------------[ cut here ]------------ > kernel BUG at kernel/time/timer.c:958! > Oops: Exception in kernel mode, sig: 5 [#1] > LE SMP NR_CPUS=2048 NUMA pSeries > Modules linked in: nfsv3 nfs_acl nfs tcp_diag udp_diag inet_diag lockd unix_diag af_packet_diag netlink_diag grace fscache sunrpc xts vmx_crypto pseries_rng sg binfmt_misc ip_tables xfs libcrc32c sd_mod ibmvscsi ibmveth scsi_transport_srp dm_mirror dm_region_hash dm_log dm_mod > CPU: 11 PID: 3067 Comm: drmgr Not tainted 4.17.0+ #179 > ... > NIP mod_timer+0x4c/0x400 > LR reset_topology_timer+0x40/0x60 > Call Trace: > 0xc0000003f9407830 (unreliable) > reset_topology_timer+0x40/0x60 > dt_update_callback+0x100/0x120 > notifier_call_chain+0x90/0x100 > __blocking_notifier_call_chain+0x60/0x90 > of_property_notify+0x90/0xd0 > of_update_property+0x104/0x150 > update_dt_property+0xdc/0x1f0 > pseries_devicetree_update+0x2d0/0x510 > post_mobility_fixup+0x7c/0xf0 > migration_store+0xa4/0xc0 > kobj_attr_store+0x30/0x60 > sysfs_kf_write+0x64/0xa0 > kernfs_fop_write+0x16c/0x240 > __vfs_write+0x40/0x200 > vfs_write+0xc8/0x240 > ksys_write+0x5c/0x100 > system_call+0x58/0x6c > > Fixes: 5d88aa85c00b ("powerpc/pseries: Update CPU maps when device tree is updated") > Cc: stable@vger.kernel.org # v3.10+ > Signed-off-by: Michael Bringmann > Signed-off-by: Michael Ellerman > > diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c > index 35ac5422903a..b5a71baedbc2 100644 > --- a/arch/powerpc/mm/numa.c > +++ b/arch/powerpc/mm/numa.c > @@ -1452,7 +1452,8 @@ static struct timer_list topology_timer; > > static void reset_topology_timer(void) > { > - mod_timer(&topology_timer, jiffies + topology_timer_secs * HZ); > + if (vphn_enabled) > + mod_timer(&topology_timer, jiffies + topology_timer_secs * HZ); > } > > #ifdef CONFIG_SMP > > -- Michael W. Bringmann Linux Technology Center IBM Corporation Tie-Line 363-5196 External: (512) 286-5196 Cell: (512) 466-0650 mwb@linux.vnet.ibm.com