slab/mempolicy: always use local policy from interrupt context

slab_node() could access current->mempolicy from interrupt context.
However there's a race condition during exit where the mempolicy
is first freed and then the pointer zeroed.

Using this from interrupts seems bogus anyways. The interrupt
will interrupt a random process and therefore get a random
mempolicy. Many times, this will be idle's, which noone can change.

Just disable this here and always use local for slab
from interrupts. I also cleaned up the callers of slab_node a bit
which always passed the same argument.

I believe the original mempolicy code did that in fact,
so it's likely a regression.

v2: send version with correct logic
v3: simplify. fix typo.
Reported-by: Arun Sharma <[email protected]>
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Andi Kleen <[email protected]>
[[email protected]: Rework control flow based on feedback from
[email protected], fix logic, and cleanup current task_struct reference]
Acked-by: David Rientjes <[email protected]>
Acked-by: Christoph Lameter <[email protected]>
Acked-by: KOSAKI Motohiro <[email protected]>
Signed-off-by: David Mackey <[email protected]>
Signed-off-by: Pekka Enberg <[email protected]>

0 files changed, 0 insertions, 0 deletions