# git rev-parse -q --verify 8604895a34d92f5e186ceb931b0d1b384030ea3d^{commit}
8604895a34d92f5e186ceb931b0d1b384030ea3d
already have revision, skipping fetch
# git checkout -q -f -B kisskb 8604895a34d92f5e186ceb931b0d1b384030ea3d
# git clean -qxdf
# < git log -1
# commit 8604895a34d92f5e186ceb931b0d1b384030ea3d
# Author: Michael Bringmann <mwb@linux.vnet.ibm.com>
# Date:   Thu Sep 20 11:45:13 2018 -0500
# 
#     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 <mwb@linux.vnet.ibm.com>
#     Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
# < /opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-gcc --version
# < git log --format=%s --max-count=1 8604895a34d92f5e186ceb931b0d1b384030ea3d
# < make -s -j 48 ARCH=powerpc O=/kisskb/build/powerpc-fixes_85xx_mpc8540_ads_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  85xx/mpc8540_ads_defconfig
# make -s -j 48 ARCH=powerpc O=/kisskb/build/powerpc-fixes_85xx_mpc8540_ads_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  
INFO: Uncompressed kernel (size 0x48816c) overlaps the address of the wrapper(0x400000)
INFO: Fixing the link_address of wrapper to (0x500000)
INFO: Uncompressed kernel (size 0x477aec) overlaps the address of the wrapper(0x400000)
INFO: Fixing the link_address of wrapper to (0x500000)
Image Name:   Linux-4.19.0-rc3-g8604895a34d9
Created:      Mon Sep 24 23:20:03 2018
Image Type:   PowerPC Linux Kernel Image (gzip compressed)
Data Size:    2346455 Bytes = 2291.46 KiB = 2.24 MiB
Load Address: 00000000
Entry Point:  00000000
Image Name:   Linux-4.19.0-rc3-g8604895a34d9
Created:      Mon Sep 24 23:20:03 2018
Image Type:   PowerPC Linux Kernel Image (gzip compressed)
Data Size:    2370159 Bytes = 2314.61 KiB = 2.26 MiB
Load Address: 00500000
Entry Point:  0050020c
Completed OK
# rm -rf /kisskb/build/powerpc-fixes_85xx_mpc8540_ads_defconfig_powerpc-gcc5
# Build took: 0:00:36.169022