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Konstantin Khlebnikov authored
This fixes use-after-free of epi->fllink.next inside list loop macro. This loop actually releases elements in the body. The list is rcu-protected but here we cannot hold rcu_read_lock because we need to lock mutex inside. The obvious solution is to use list_for_each_entry_safe(). RCU-ness isn't essential because nobody can change this list under us, it's final fput for this file. The bug was introduced by ae10b2b4 ("epoll: optimize EPOLL_CTL_DEL using rcu") Signed-off-by:
Konstantin Khlebnikov <koct9i@gmail.com> Reported-by:
Cyrill Gorcunov <gorcunov@openvz.org> Cc: Stable <stable@vger.kernel.org> # 3.13+ Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Jason Baron <jbaron@akamai.com> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
ebe06187