[ Upstream commit cc9b364bb1d58d3dae270c7a931a8cc717dc2b3b ]
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 <zhangchangzhong@huawei.com>
Reviewed-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
