linux/kernel/power
Colin Cross 2b44c4db2e freezer: set PF_SUSPEND_TASK flag on tasks that call freeze_processes
Calling freeze_processes sets a global flag that will cause any
process that calls try_to_freeze to enter the refrigerator.  It
skips sending a signal to the current task, but if the current
task ever hits try_to_freeze, all threads will be frozen and the
system will deadlock.

Set a new flag, PF_SUSPEND_TASK, on the task that calls
freeze_processes.  The flag notifies the freezer that the thread
is involved in suspend and should not be frozen.  Also add a
WARN_ON in thaw_processes if the caller does not have the
PF_SUSPEND_TASK flag set to catch if a different task calls
thaw_processes than the one that called freeze_processes, leaving
a task with PF_SUSPEND_TASK permanently set on it.

Threads that spawn off a task with PF_SUSPEND_TASK set (which
swsusp does) will also have PF_SUSPEND_TASK set, preventing them
from freezing while they are helping with suspend, but they need
to be dead by the time suspend is triggered, otherwise they may
run when userspace is expected to be frozen.  Add a WARN_ON in
thaw_processes if more than one thread has the PF_SUSPEND_TASK
flag set.

Reported-and-tested-by: Michael Leun <lkml20130126@newton.leun.net>
Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-07-30 14:05:06 +02:00
..
Kconfig Merge branch 'for-3.11' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq 2013-07-02 19:53:30 -07:00
Makefile PM / Sleep: Add user space interface for manipulating wakeup sources, v3 2012-05-01 21:26:05 +02:00
autosleep.c PM / Sleep: avoid 'autosleep' in shutdown progress 2013-07-15 01:31:37 +02:00
block_io.c block: kill off REQ_UNPLUG 2011-03-10 08:52:27 +01:00
console.c PM: make VT switching to the suspend console optional v3 2013-02-20 01:33:41 +01:00
hibernate.c Power management updates for 3.6 2012-07-22 13:36:52 -07:00
main.c PM / Sleep: Warn about system time after resume with pm_trace 2013-06-27 22:14:46 +02:00
power.h PM / Hibernate: Enable suspend to both for in-kernel hibernation. 2012-07-01 13:31:22 +02:00
poweroff.c power/sysrq: fix inconstistent help message of sysrq key 2013-04-30 17:04:10 -07:00
process.c freezer: set PF_SUSPEND_TASK flag on tasks that call freeze_processes 2013-07-30 14:05:06 +02:00
qos.c PM / QoS: Add pm_qos_request tracepoints 2013-06-24 13:09:03 +02:00
snapshot.c Merge branch 'akpm' (updates from Andrew Morton) 2013-07-03 17:12:13 -07:00
suspend.c PM / wakeup: Adjust messaging for wake events during suspend 2013-06-11 23:53:37 +02:00
suspend_test.c driver-core: constify data for class_find_device() 2013-02-06 12:18:56 -08:00
swap.c PM / Hibernate: use rb_entry 2012-11-15 00:37:08 +01:00
user.c Make wait_for_device_probe() also do scsi_complete_async_scans() 2012-07-18 18:15:46 -07:00
wakelock.c PM / Sleep: Require CAP_BLOCK_SUSPEND to use wake_lock/wake_unlock 2012-07-19 00:00:58 +02:00