On 2019/3/1 16:43, Sergei Shtylyov wrote:
Hello!

On 01.03.2019 8:56, Su Yanjun wrote:

From: Su Yanjun <suyj.f...@cn.fujitsu.com>

Because nf_conntrack_helper_unregister maybe used in an unloadable module,
it uses 'synchronize_rcu' which may cause kernel panic.

According to the artical:

   Article?

I got it.
RCU and Unloadable Modules
https://lwn.net/Articles/217484/

When we have a heavy rcu callback load, then some of the callbacks might be deferred in order to allow other processing to proceed. sychnorize_rcu does not wait rcu callback complete and module may be unloaded before callback
done.

This patch uses rcu_barrier instead of synchronize_rcu will prevent this
                                                        ^ that/which missed?

Yes.
situation.

Signed-off-by: Su Yanjun <suyj.f...@cn.fujitsu.com>
[...]

MBR, Sergei


Thanks.

Su




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