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95278ddaa1
In commitec3ed293e7("net_sched: change tcf_del_walker() to take idrinfo->lock") we move fl_hw_destroy_tmplt() to a workqueue to avoid blocking with the spinlock held. Unfortunately, this causes a lot of troubles here: 1. tcf_chain_destroy() could be called right after we queue the work but before the work runs. This is a use-after-free. 2. The chain refcnt is already 0, we can't even just hold it again. We can check refcnt==1 but it is ugly. 3. The chain with refcnt 0 is still visible in its block, which means it could be still found and used! 4. The block has a refcnt too, we can't hold it without introducing a proper API either. We can make it working but the end result is ugly. Instead of wasting time on reviewing it, let's just convert the troubling spinlock to a mutex, which allows us to use non-atomic allocations too. Fixes:ec3ed293e7("net_sched: change tcf_del_walker() to take idrinfo->lock") Reported-by: Ido Schimmel <idosch@idosch.org> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Vlad Buslov <vladbu@mellanox.com> Cc: Jiri Pirko <jiri@mellanox.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Tested-by: Ido Schimmel <idosch@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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.
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.