1a2b27f2d7
[ Upstream commit e72eeab542dbf4f544e389e64fa13b82a1b6d003 ]
I received a bug report (no reproducer so far) where we trip over
712 rcu_read_lock();
713 ct_hook = rcu_dereference(nf_ct_hook);
714 BUG_ON(ct_hook == NULL); // here
In nf_conntrack_destroy().
First turn this BUG_ON into a WARN. I think it was triggered
via enable_hooks=1 flag.
When this flag is turned on, the conntrack hooks are registered
before nf_ct_hook pointer gets assigned.
This opens a short window where packets enter the conntrack machinery,
can have skb->_nfct set up and a subsequent kfree_skb might occur
before nf_ct_hook is set.
Call nf_conntrack_init_end() to set nf_ct_hook before we register the
pernet ops.
Fixes: ba3fbe663635 ("netfilter: nf_conntrack: provide modparam to always register conntrack hooks")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.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.