mac80211: mesh: fix call_rcu() usage
When using call_rcu(), the called function may be delayed quite significantly, and without a matching rcu_barrier() there's no way to be sure it has finished. Therefore, global state that could be gone/freed/reused should never be touched in the callback. Fix this in mesh by moving the atomic_dec() into the caller; that's not really a problem since we already unlinked the path and it will be destroyed anyway. This fixes a crash Jouni observed when running certain tests in a certain order, in which the mesh interface was torn down, the memory reused for a function pointer (work struct) and running that then crashed since the pointer had been decremented by 1, resulting in an invalid instruction byte stream. Cc: stable@vger.kernel.org Fixes: eb2b9311 ("mac80211: mesh path table implementation") Reported-by: Jouni Malinen <j@w1.fi> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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