rcu: Export debug_init_rcu_head() and and debug_init_rcu_head()

Currently, call_rcu() relies on implicit allocation and initialization
for the debug-objects handling of RCU callbacks.  If you hammer the
kernel hard enough with Sasha's modified version of trinity, you can end
up with the sl*b allocators recursing into themselves via this implicit
call_rcu() allocation.

This commit therefore exports the debug_init_rcu_head() and
debug_rcu_head_free() functions, which permits the allocators to allocated
and pre-initialize the debug-objects information, so that there no longer
any need for call_rcu() to do that initialization, which in turn prevents
the recursion into the memory allocators.

Reported-by: Sasha Levin <[email protected]>
Suggested-by: Thomas Gleixner <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
Acked-by: Thomas Gleixner <[email protected]>
Looks-good-to: Christoph Lameter <[email protected]>

0 files changed, 0 insertions, 0 deletions