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author | Tejun Heo <tj@kernel.org> | 2011-11-21 12:32:22 -0800 |
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committer | Tejun Heo <tj@kernel.org> | 2011-11-21 12:32:22 -0800 |
commit | 50fb4f7fc907efff65eadb0b74387a9ffed6e849 (patch) | |
tree | e3392afa49a97c187d7e63f3fee862aef9e342ed /drivers/bluetooth | |
parent | 6fe4c6d466e95d31164f14b1ac4aefb51f0f4f82 (diff) | |
download | op-kernel-dev-50fb4f7fc907efff65eadb0b74387a9ffed6e849.zip op-kernel-dev-50fb4f7fc907efff65eadb0b74387a9ffed6e849.tar.gz |
freezer: fix current->state restoration race in refrigerator()
refrigerator() saves current->state before entering frozen state and
restores it before returning using __set_current_state(); however,
this is racy, for example, please consider the following sequence.
set_current_state(TASK_INTERRUPTIBLE);
try_to_freeze();
if (kthread_should_stop())
break;
schedule();
If kthread_stop() races with ->state restoration, the restoration can
restore ->state to TASK_INTERRUPTIBLE after kthread_stop() sets it to
TASK_RUNNING but kthread_should_stop() may still see zero
->should_stop because there's no memory barrier between restoring
TASK_INTERRUPTIBLE and kthread_should_stop() test.
This isn't restricted to kthread_should_stop(). current->state is
often used in memory barrier based synchronization and silently
restoring it w/o mb breaks them.
Use set_current_state() instead.
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'drivers/bluetooth')
0 files changed, 0 insertions, 0 deletions