linux_dsm_epyc7002/arch
Thiago Jung Bauermann 3e401f7a2e powerpc: Only obtain cpu_hotplug_lock if called by rtasd
Calling arch_update_cpu_topology from a CPU hotplug state machine callback
hits a deadlock because the function tries to get a read lock on
cpu_hotplug_lock while the state machine still holds a write lock on it.

Since all callers of arch_update_cpu_topology except rtasd already hold
cpu_hotplug_lock, this patch changes the function to use
stop_machine_cpuslocked and creates a separate function for rtasd which
still tries to obtain the lock.

Michael Bringmann investigated the bug and provided a detailed analysis
of the deadlock on this previous RFC for an alternate solution:

Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: John Allen <jallen@linux.vnet.ibm.com>
Cc: Michael Bringmann <mwb@linux.vnet.ibm.com>
Cc: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/1497996510-4032-1-git-send-email-bauerman@linux.vnet.ibm.com
Link: https://patchwork.ozlabs.org/patch/771293/
2017-06-23 09:32:11 +02:00
..
alpha osf_wait4(): fix infoleak 2017-05-21 13:10:07 -04:00
arc Kbuild UAPI header export updates for v4.12 2017-05-10 20:45:36 -07:00
arm ARM/hw_breakpoint: Fix possible recursive locking for arch_hw_breakpoint_init 2017-06-20 12:25:22 +02:00
arm64 arm64: Prevent cpu hotplug rwsem recursion 2017-05-26 10:10:45 +02:00
blackfin uapi: export all headers under uapi directories 2017-05-11 00:21:54 +09:00
c6x uapi: export all headers under uapi directories 2017-05-11 00:21:54 +09:00
cris devicetree: Move include prefixes from arch to separate directory 2017-05-18 23:55:48 -07:00
frv Kbuild UAPI header export updates for v4.12 2017-05-10 20:45:36 -07:00
h8300 uapi: export all headers under uapi directories 2017-05-11 00:21:54 +09:00
hexagon uapi: export all headers under uapi directories 2017-05-11 00:21:54 +09:00
ia64 Kbuild UAPI header export updates for v4.12 2017-05-10 20:45:36 -07:00
m32r uapi: export all headers under uapi directories 2017-05-11 00:21:54 +09:00
m68k uapi: export all headers under uapi directories 2017-05-11 00:21:54 +09:00
metag devicetree: Move include prefixes from arch to separate directory 2017-05-18 23:55:48 -07:00
microblaze uapi: export all headers under uapi directories 2017-05-11 00:21:54 +09:00
mips jump_label: Reorder hotplug lock and jump_label_lock 2017-05-26 10:10:45 +02:00
mn10300 uapi: export all headers under uapi directories 2017-05-11 00:21:54 +09:00
nios2 nios2 update for v4.12-rc1 2017-05-12 09:53:16 -07:00
openrisc uapi: export all headers under uapi directories 2017-05-11 00:21:54 +09:00
parisc uapi: export all headers under uapi directories 2017-05-11 00:21:54 +09:00
powerpc powerpc: Only obtain cpu_hotplug_lock if called by rtasd 2017-06-23 09:32:11 +02:00
s390 s390: Prevent hotplug rwsem recursion 2017-05-26 10:10:46 +02:00
score uapi: export all headers under uapi directories 2017-05-11 00:21:54 +09:00
sh Kbuild UAPI header export updates for v4.12 2017-05-10 20:45:36 -07:00
sparc jump_label: Reorder hotplug lock and jump_label_lock 2017-05-26 10:10:45 +02:00
tile jump_label: Reorder hotplug lock and jump_label_lock 2017-05-26 10:10:45 +02:00
um Merge branch 'for-linus-4.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml 2017-05-13 10:20:02 -07:00
unicore32 Kbuild UAPI header export updates for v4.12 2017-05-10 20:45:36 -07:00
x86 jump_label: Reorder hotplug lock and jump_label_lock 2017-05-26 10:10:45 +02:00
xtensa uapi: export all headers under uapi directories 2017-05-11 00:21:54 +09:00
.gitignore
Kconfig Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-05-10 10:30:46 -07:00