Re: [Patch nf] netfilter: xt_hashlimit: unregister proc file before releasing mutex

On Tue, Feb 18, 2020 at 1:35 PM Pablo Neira Ayuso [off-list ref] wrote:

On Wed, Feb 12, 2020 at 10:53:52PM -0800, Cong Wang wrote:

quoted

Before releasing the global mutex, we only unlink the hashtable
from the hash list, its proc file is still not unregistered at
this point. So syzbot could trigger a race condition where a
parallel htable_create() could register the same file immediately
after the mutex is released.

Move htable_remove_proc_entry() back to mutex protection to
fix this. And, fold htable_destroy() into htable_put() to make
the code slightly easier to understand.

Probably revert previous one?

The hung task could appear again if we move the cleanup
back under mutex.