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af370ab36f
nf_queue is problematic when another NF_QUEUE invocation happens
from nf_reinject().
1. nf_queue is invoked, increments state->sk refcount.
2. skb is queued, waiting for verdict.
3. sk is closed/released.
3. verdict comes back, nf_reinject is called.
4. nf_reinject drops the reference -- refcount can now drop to 0
Instead of get_ref/release_ref pattern, we need to nest the get_ref calls:
get_ref
get_ref
release_ref
release_ref
So that when we invoke the next processing stage (another netfilter
or the okfn()), we hold at least one reference count on the
devices/socket.
After previous patch, it is now safe to put the entry even after okfn()
has potentially free'd the skb.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
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.