linux_dsm_epyc7002/arch
Michael Bringmann 8604895a34 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: 5d88aa85c0 ("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>
2018-09-24 21:05:38 +10:00
..
alpha Merge branch 'userns-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2018-08-24 09:25:39 -07:00
arc ARC: don't check for HIGHMEM pages in arch_dma_alloc 2018-09-04 13:21:38 -07:00
arm Fixes for KVM/ARM for Linux v4.19 v2: 2018-09-07 18:38:25 +02:00
arm64 KVM fixes for 4.19-rc3 2018-09-08 15:52:45 -07:00
c6x kbuild: rename LDFLAGS to KBUILD_LDFLAGS 2018-08-24 08:22:08 +09:00
h8300 Kbuild updates for v4.19 (2nd) 2018-08-25 13:40:38 -07:00
hexagon kbuild: rename LDFLAGS to KBUILD_LDFLAGS 2018-08-24 08:22:08 +09:00
ia64 ia64: Fix allnoconfig section mismatch for ioc_init/ioc_iommu_info 2018-08-22 14:12:47 -07:00
m68k m68k: fix early memory reservation for ColdFire MMU systems 2018-09-03 10:19:36 +10:00
microblaze kbuild: rename LDFLAGS to KBUILD_LDFLAGS 2018-08-24 08:22:08 +09:00
mips KVM fixes for 4.19-rc3 2018-09-08 15:52:45 -07:00
nds32 nds32: linker script: GCOV kernel may refers data in __exit 2018-09-05 10:16:26 +08:00
nios2 nios2: kconfig: remove duplicate DEBUG_STACK_USAGE symbol defintions 2018-08-27 09:47:20 +08:00
openrisc OpenRISC updates for 4.19 2018-08-23 14:09:37 -07:00
parisc Merge branch 'parisc-4.19-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux 2018-08-22 14:06:37 -07:00
powerpc powerpc/pseries: Fix unitialized timer reset on migration 2018-09-24 21:05:38 +10:00
riscv RISC-V: Use a less ugly workaround for unused variable warnings 2018-08-28 12:58:36 -07:00
s390 KVM: s390: Properly lock mm context allow_gmap_hpage_1m setting 2018-09-04 11:40:26 +02:00
sh kbuild: rename LDFLAGS to KBUILD_LDFLAGS 2018-08-24 08:22:08 +09:00
sparc sparc: set a default 32-bit dma mask for OF devices 2018-09-02 10:02:04 +02:00
um kbuild: rename LDFLAGS to KBUILD_LDFLAGS 2018-08-24 08:22:08 +09:00
unicore32 mm: convert return type of handle_mm_fault() caller to vm_fault_t 2018-08-17 16:20:28 -07:00
x86 Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-09-09 07:05:15 -07:00
xtensa Kbuild updates for v4.19 (2nd) 2018-08-25 13:40:38 -07:00
.gitignore
Kconfig Merge branch 'tlb-fixes' 2018-08-23 14:55:01 -07:00