On Fri, Sep 15, 2023 at 07:20:41PM +0800, Zhang Changzhong wrote:
> There are race conditions that may lead to inet6_dev refcount underflow
> in xfrm6_dst_destroy() and rt6_uncached_list_flush_dev().
>
> One of the refcount underflow bugs is shown below:
> (cpu 1) | (cpu 2)
> xfrm6_dst_destroy() |
> ... |
> in6_dev_put() |
> | rt6_uncached_list_flush_dev()
> ... | ...
> | in6_dev_put()
> rt6_uncached_list_del() | ...
> ... |
>
> xfrm6_dst_destroy() calls rt6_uncached_list_del() after in6_dev_put(),
> so rt6_uncached_list_flush_dev() has a chance to call in6_dev_put()
> again for the same inet6_dev.
>
> Fix it by moving in6_dev_put() after rt6_uncached_list_del() in
> xfrm6_dst_destroy().
>
> Fixes: 510c321b5571 ("xfrm: reuse uncached_list to track xdsts")
> Signed-off-by: Zhang Changzhong <[email protected]>
Applied, thanks a lot!