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Cong Wang
822e86d997
In commit7aa0045dad("net_sched: introduce a workqueue for RCU callbacks of tc filter") I defer tcf_chain_flush() to a workqueue, this causes a use-after-free because qdisc is already destroyed after we queue this work. The tcf_block_put_deferred() is no longer necessary after we get RTNL for each tc filter destroy work, no others could jump in at this point. Same for tcf_chain_hold(), we are fully serialized now. This also reduces one indirection therefore makes the code more readable. Note this brings back a rcu_barrier(), however comparing to the code prior to commit7aa0045dadwe still reduced one rcu_barrier(). For net-next, we can consider to refcnt tcf block to avoid it. Fixes:7aa0045dad("net_sched: introduce a workqueue for RCU callbacks of tc filter") Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Jiri Pirko <jiri@resnulli.us> Cc: John Fastabend <john.fastabend@gmail.com> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Eric Dumazet <edumazet@google.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.