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<p class="MsoNormal">Hello,<o:p></o:p></p>
<p class="MsoNormal">I’ve noticed the wpa_supplicant process on my mesh interfaces leaking memory to the point that the kernel kills the process.<o:p></o:p></p>
<p class="MsoNormal">It was discovered in 18.06.2, but I’ve reproduced it with 18.06.4 and with the master branch from the GitHub repo. Since the leak occurs as mesh links are created and destroyed, I was able to reproduce it with a simple two-node setup where
I monitor the wpa_supplicant process VSZ on one node and repeatedly bring wifi up and down on the other node.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I’ve traced it back to the 18.06.2 release, specifically to lines 34-35 of package/network/services/hostapd/patches/015-mesh-do-not-use-offchan-mgmt-tx-on-DFS.patch
<o:p></o:p></p>
<p class="MsoNormal">+ (modes = nl80211_get_hw_feature_data(bss, &num_modes, &flags,<o:p></o:p></p>
<p class="MsoNormal">+ &dfs_domain)) &&<o:p></o:p></p>
<p class="MsoNormal">That code was added in a35f24309021c1c0e9cbed0faedf58b941cb4bd3.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I removed the entire patch file to resolve the memory leak because the subsequent call to ieee80211_is_dfs() uses the return value from nl80211_get_hw_feature_data(). However, I know the problem is specifically related to the nl80211_get_hw_feature_data()
call because I stepped-backward through commits of the hostapd source until I got back to 0f7fc6b98de9c69f511b9b22f2b65553126362eb, where ieee80211_is_dfs() had only one argument and didn’t rely on the nl80211_get_hw_feature_data() return value. At that point,
the memory leak still occurred until I commented-out the call to nl80211_get_hw_feature_data().<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I attempted to dive into nl80211_get_hw_feature_data(), but was quickly lost, so I defer to those that are more experienced in that code.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Test platform: Compex WPJ-531 (ar71xx)<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thanks,<o:p></o:p></p>
<p class="MsoNormal">-Nick<o:p></o:p></p>
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