Messages in this thread | | | Subject | Re: [PATCH] netfilter: nf_ct_helper: Fix possible panic when nf_conntrack_helper_unregister is used in an unloadable module | From | "Su Yanjun <>" <> | Date | Fri, 1 Mar 2019 17:08:23 +0800 |
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On 2019/3/1 16:43, Sergei Shtylyov wrote: > Hello! > > On 01.03.2019 8:56, Su Yanjun wrote: > >> From: Su Yanjun <suyj.fnst@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.fnst@cn.fujitsu.com> > [...] > > MBR, Sergei > > Thanks.
Su
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