linux/arch
Robert Jennings 3be7db6ab4 powerpc: VPHN topology change updates all siblings
When an associativity level change is found for one thread, the
siblings threads need to be updated as well.  This is done today
for PRRN in stage_topology_update() but is missing for VPHN in
update_cpu_associativity_changes_mask().  This patch will correctly
update all thread siblings during a topology change.

Without this patch a topology update can result in a CPU in
init_sched_groups_power() getting stuck indefinitely in a loop.

This loop is built in build_sched_groups(). As a result of the thread
moving to a node separate from its siblings the struct sched_group will
have its next pointer set to point to itself rather than the sched_group
struct of the next thread.  This happens because we have a domain without
the SD_OVERLAP flag, which is correct, and a topology that doesn't conform
with reality (threads on the same core assigned to different numa nodes).
When this list is traversed by init_sched_groups_power() it will reach
the thread's sched_group structure and loop indefinitely; the cpu will
be stuck at this point.

The bug was exposed when VPHN was enabled in commit b7abef0 (v3.9).

Cc: <stable@vger.kernel.org> [v3.9+]
Reported-by: Jan Stancek <jstancek@redhat.com>
Signed-off-by: Robert Jennings <rcj@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-08-01 13:11:47 +10:00
..
alpha alpha: delete __cpuinit usage from all users 2013-07-14 19:36:51 -04:00
arc Couple of Platform updates (Device Tree files primarily) given that the 2013-07-10 10:11:26 -07:00
arm Power management and ACPI fixes for 3.11-rc2 2013-07-19 09:59:06 -07:00
arm64 - Post -rc1 update to the common reboot infrastructure. 2013-07-19 15:08:53 -07:00
avr32 net: rename busy poll socket op and globals 2013-07-10 17:08:27 -07:00
blackfin Merge branch 'cpuinit_phase2' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux 2013-07-18 10:50:26 -07:00
c6x Merge branch 'akpm' (updates from Andrew Morton) 2013-07-03 17:12:13 -07:00
cris cris: delete __cpuinit usage from all cris files 2013-07-14 19:36:54 -04:00
frv frv: delete __cpuinit usage from all frv files 2013-07-14 19:36:55 -04:00
h8300 net: rename busy poll socket op and globals 2013-07-10 17:08:27 -07:00
hexagon hexagon: delete __cpuinit usage from all hexagon files 2013-07-14 19:36:55 -04:00
ia64 net: rename busy poll socket op and globals 2013-07-10 17:08:27 -07:00
m32r m32r: delete __cpuinit usage from all m32r files 2013-07-14 19:36:55 -04:00
m68k Merge branch 'akpm' (updates from Andrew Morton) 2013-07-03 17:12:13 -07:00
metag metag: delete __cpuinit usage from all metag files 2013-07-14 19:36:54 -04:00
microblaze Merge branch 'next' of git://git.monstr.eu/linux-2.6-microblaze 2013-07-10 10:16:07 -07:00
mips Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2013-07-19 15:10:01 -07:00
mn10300 net: rename busy poll socket op and globals 2013-07-10 17:08:27 -07:00
openrisc openrisc: delete __cpuinit usage from all openrisc files 2013-07-14 19:36:55 -04:00
parisc parisc: delete __cpuinit usage from all users 2013-07-14 19:36:51 -04:00
powerpc powerpc: VPHN topology change updates all siblings 2013-08-01 13:11:47 +10:00
s390 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux 2013-07-19 15:08:12 -07:00
score score: delete __cpuinit usage from all score files 2013-07-14 19:36:56 -04:00
sh sh: delete __cpuinit usage from all sh files 2013-07-14 19:36:53 -04:00
sparc sparc: delete __cpuinit/__CPUINIT usage from all users 2013-07-14 19:36:52 -04:00
tile tile: delete __cpuinit usage from all tile files 2013-07-14 19:36:54 -04:00
um um: siginfo cleanup 2013-07-19 11:31:36 +02:00
unicore32 reboot: move arch/x86 reboot= handling to generic kernel 2013-07-09 10:33:29 -07:00
x86 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml 2013-07-19 15:11:09 -07:00
xtensa xtensa: delete __cpuinit usage from all xtensa files 2013-07-14 19:36:56 -04:00
.gitignore
Kconfig mm: soft-dirty bits for user memory changes tracking 2013-07-03 16:07:26 -07:00