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SubjectRe: [RFC] Add BPF_SYNCHRONIZE bpf(2) command
<div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On Sat, Jul 14, 2018 at 11:18 AM, Joel Fernandes <span dir="ltr">&lt;<a href="mailto:joel@joelfernandes.org" target="_blank">joel@joelfernandes.org</a>&gt;</span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">By the way just curious I was briefly going through kernel/bpf/arraymap.c.<br>
How are you protecting against load-store tearing of values of array map<br>
updates/lookups?<br>
<br>
For example, if userspace reads an array map at a particular index, while<br>
another CPU is updating it, then userspace can read partial values /<br>
half-updated values right? Since rcu_read_lock is in use, I was hoping to<br>
find something like rcu_assign_pointer there to protect readers against<br>
concurrent updates.  Thanks for any clarification.</blockquote><div><br></div><div>I&#39;m also curious about the answer to this question. </div></div></div></div>
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