linux/arch/powerpc
Anton Vorontsov 73863ab028 powerpc: use clear_tasks_mm_cpumask()
Current CPU hotplug code has some task->mm handling issues:

1. Working with task->mm w/o getting mm or grabing the task lock is
   dangerous as ->mm might disappear (exit_mm() assigns NULL under
   task_lock(), so tasklist lock is not enough).

   We can't use get_task_mm()/mmput() pair as mmput() might sleep,
   so we must take the task lock while handle its mm.

2. Checking for process->mm is not enough because process' main
   thread may exit or detach its mm via use_mm(), but other threads
   may still have a valid mm.

   To fix this we would need to use find_lock_task_mm(), which would
   walk up all threads and returns an appropriate task (with task
   lock held).

clear_tasks_mm_cpumask() has all the issues fixed, so let's use it.

Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 17:49:29 -07:00
..
boot arm-soc: driver specific updates 2012-05-26 12:22:27 -07:00
configs Sound updates for 3.5-rc1 2012-05-23 13:05:43 -07:00
include/asm powerpc: Use the new generic strncpy_from_user() and strnlen_user() 2012-05-27 21:00:07 -07:00
kernel powerpc: Use the new generic strncpy_from_user() and strnlen_user() 2012-05-27 21:00:07 -07:00
kvm Merge branch 'next' of git://git.kernel.org/pub/scm/virt/kvm/kvm 2012-05-24 16:17:30 -07:00
lib powerpc: Use the new generic strncpy_from_user() and strnlen_user() 2012-05-27 21:00:07 -07:00
math-emu powerpc/math_emu/efp: Look for errata handler when type mismatches 2011-10-06 23:36:47 -05:00
mm powerpc: use clear_tasks_mm_cpumask() 2012-05-31 17:49:29 -07:00
net bpf jit: Let the powerpc jit handle negative offsets 2012-04-30 13:40:50 -04:00
oprofile Disintegrate asm/system.h for PowerPC 2012-03-28 18:30:02 +01:00
perf perf: Pass last sampling period to perf_sample_data_init() 2012-05-09 15:23:12 +02:00
platforms avoid iput() from flusher thread 2012-05-28 09:54:45 -07:00
sysdev Merge remote-tracking branch 'jwb/next' into next 2012-05-10 12:58:24 +10:00
xmon Disintegrate and delete asm/system.h 2012-03-28 15:58:21 -07:00
Kconfig powerpc: Use the new generic strncpy_from_user() and strnlen_user() 2012-05-27 21:00:07 -07:00
Kconfig.debug irqdomain: Remove powerpc dependency from debugfs file 2012-03-29 14:31:02 -06:00
Makefile powerpc/crypto: Build files for the nx device driver 2012-05-16 15:05:45 +10:00
relocs_check.pl powerpc: Process dynamic relocations for kernel 2011-12-20 10:21:08 -05:00