61fd38db76
[ Upstream commit cc8e58f8325cdf14b9516b61c384cdfd02a4f408 ] The following deadlock scenario is triggered by syzbot: Thread A: Thread B: tcf_idr_check_alloc() ... populate_metalist() rtnl_unlock() rtnl_lock() ... request_module() tcf_idr_check_alloc() rtnl_lock() At this point, thread A is waiting for thread B to release RTNL lock, while thread B is waiting for thread A to commit the IDR change with tcf_idr_insert() later. Break this deadlock situation by preloading ife modules earlier, before tcf_idr_check_alloc(), this is fine because we only need to load modules we need potentially. Reported-and-tested-by: syzbot+80e32b5d1f9923f8ace6@syzkaller.appspotmail.com Fixes: 0190c1d452a9 ("net: sched: atomically check-allocate action") Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Vlad Buslov <vladbu@mellanox.com> Cc: Jiri Pirko <jiri@resnulli.us> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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.