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<a href="https://gitlab.rtems.org/chris">Chris Johns</a> created an issue: <a href="https://gitlab.rtems.org/rtems/pkg/rtems-libbsd/-/issues/8">#8</a>
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Assignee: Chris Johns
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<h2 dir="auto" style="font-size: 1.5em; font-weight: 600; padding-bottom: .3em; border-bottom-width: 1px; border-bottom-color: #bfbfc3; border-bottom-style: solid; color: #28272d; margin: 0 0 16px;" align="initial">
<a href="#summary" aria-hidden="true" class="anchor" id="user-content-summary" style="margin-top: 0; float: left; margin-left: -20px; text-decoration: none; outline: none;"></a>Summary</h2>
<p dir="auto" style="color: #28272d; margin: 0 0 16px;" align="initial">Code sometimes crashes after <code style='font-size: 90%; color: #18171d; word-wrap: break-word; background-color: #ececef; border-radius: .25rem; margin-top: 0; font-weight: inherit; font-family: "GitLab Mono","JetBrains Mono","Menlo","DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; vertical-align: bottom; white-space: pre-wrap; overflow-wrap: break-word; word-break: keep-all; padding: 2px 4px;'>dhcpcd</code> starts but not always. It depends on the gap between the interface being assigned an address, something else requesting heap memory, how that memory is used and the configuration of the DHCP server.</p>
<p dir="auto" style="color: #28272d; margin: 0 0 16px;" align="initial">I have a hard crash on an KR260 board with two interfaces mounting an NFSv4 export soon after <code style='font-size: 90%; color: #18171d; word-wrap: break-word; background-color: #ececef; border-radius: .25rem; margin-top: 0; font-weight: inherit; font-family: "GitLab Mono","JetBrains Mono","Menlo","DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; vertical-align: bottom; white-space: pre-wrap; overflow-wrap: break-word; word-break: keep-all; padding: 2px 4px;'>dhcpcd</code> as started and an interface being assigned an IP4 address. Debugging the crash I discovered the location being changed was the upper 32bits of a XDR buffer pointer and the update correlated to index 324 of the <code style='font-size: 90%; color: #18171d; word-wrap: break-word; background-color: #ececef; border-radius: .25rem; font-weight: inherit; font-family: "GitLab Mono","JetBrains Mono","Menlo","DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; vertical-align: bottom; white-space: pre-wrap; overflow-wrap: break-word; word-break: keep-all; padding: 2px 4px;'>requiremask6</code> fields of the <code style='font-size: 90%; color: #18171d; word-wrap: break-word; background-color: #ececef; border-radius: .25rem; font-weight: inherit; font-family: "GitLab Mono","JetBrains Mono","Menlo","DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; vertical-align: bottom; white-space: pre-wrap; overflow-wrap: break-word; word-break: keep-all; padding: 2px 4px;'>struct if_options</code> that is allocated then <code style='font-size: 90%; color: #18171d; word-wrap: break-word; background-color: #ececef; border-radius: .25rem; font-weight: inherit; font-family: "GitLab Mono","JetBrains Mono","Menlo","DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; vertical-align: bottom; white-space: pre-wrap; overflow-wrap: break-word; word-break: keep-all; padding: 2px 4px;'>dhcpcd</code> first reads its configuration.</p>
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<pre class="code highlight js-syntax-highlight language-plaintext" v-pre="true" style='display: block; font-size: 14px; color: #28272d; line-height: 1.6em; overflow-x: auto; border-radius: .25rem; position: relative; font-family: "GitLab Mono","JetBrains Mono","Menlo","DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; word-break: break-all; word-wrap: break-word; background-color: #fbfafd; margin: 0 0 16px; padding: 12px; border: 1px solid #dcdcde;'><code style='font-size: inherit; color: inherit; word-wrap: normal; word-break: keep-all; background-color: inherit; border-radius: .25rem; white-space: pre; margin-top: 0; font-family: "GitLab Mono","JetBrains Mono","Menlo","DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; vertical-align: bottom; overflow-wrap: normal; padding: unset;'><span id="LC1" class="line" lang="plaintext" style="margin-top: 0;">(gdb) p 0xa5010c - (int) &ifo->requiremask6 </span>
<span id="LC2" class="line" lang="plaintext">$26 = 324 </span></code></pre>
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<p dir="auto" style="color: #28272d; margin: 0 0 16px;" align="initial">I have seen random failures and crashes on Zynq systems I could not track it down. I now believe those are related. <code style='font-size: 90%; color: #18171d; word-wrap: break-word; background-color: #ececef; border-radius: .25rem; margin-top: 0; font-weight: inherit; font-family: "GitLab Mono","JetBrains Mono","Menlo","DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; vertical-align: bottom; white-space: pre-wrap; overflow-wrap: break-word; word-break: keep-all; padding: 2px 4px;'>dhcpcd</code> frees the read options before it enters the event loop and there must be a reference some where.</p>
<h2 dir="auto" style="font-size: 1.5em; font-weight: 600; padding-bottom: .3em; border-bottom-width: 1px; border-bottom-color: #bfbfc3; border-bottom-style: solid; color: #28272d; margin: 24px 0 16px;" align="initial">
<a href="#steps-to-reproduce" aria-hidden="true" class="anchor" id="user-content-steps-to-reproduce" style="margin-top: 0; float: left; margin-left: -20px; text-decoration: none; outline: none;"></a>Steps to reproduce</h2>
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<li style="margin-top: 0; line-height: 1.6em; margin-left: 25px; padding-left: 3px;">Use an AARCH64 BSP and build <code style='font-size: 90%; color: #18171d; word-wrap: break-word; background-color: #ececef; border-radius: .25rem; margin-top: 0; font-family: "GitLab Mono","JetBrains Mono","Menlo","DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; vertical-align: bottom; white-space: pre-wrap; overflow-wrap: break-word; word-break: keep-all; padding: 2px 4px;'>6-freebsd-12</code>
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<li style="line-height: 1.6em; margin-left: 25px; padding-left: 3px;">Configure 2 interfaces</li>
<li style="line-height: 1.6em; margin-left: 25px; padding-left: 3px;">Use the default <code style='font-size: 90%; color: #18171d; word-wrap: break-word; background-color: #ececef; border-radius: .25rem; margin-top: 0; font-family: "GitLab Mono","JetBrains Mono","Menlo","DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; vertical-align: bottom; white-space: pre-wrap; overflow-wrap: break-word; word-break: keep-all; padding: 2px 4px;'>dhcpcd</code> configuration with the options of <code style='font-size: 90%; color: #18171d; word-wrap: break-word; background-color: #ececef; border-radius: .25rem; font-family: "GitLab Mono","JetBrains Mono","Menlo","DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; vertical-align: bottom; white-space: pre-wrap; overflow-wrap: break-word; word-break: keep-all; padding: 2px 4px;'>--debug --nobackground --timeout 30</code>
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<li style="line-height: 1.6em; margin-left: 25px; padding-left: 3px;">Mount and NSFv4 export soon after the interfaces are assigned IP4 addresses</li>
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<h2 dir="auto" style="font-size: 1.5em; font-weight: 600; padding-bottom: .3em; border-bottom-width: 1px; border-bottom-color: #bfbfc3; border-bottom-style: solid; color: #28272d; margin: 24px 0 16px;" align="initial">
<a href="#analysis" aria-hidden="true" class="anchor" id="user-content-analysis" style="margin-top: 0; float: left; margin-left: -20px; text-decoration: none; outline: none;"></a>Analysis</h2>
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<li style="margin-top: 0; line-height: 1.6em; margin-left: 25px; padding-left: 3px;">The <code style='font-size: 90%; color: #18171d; word-wrap: break-word; background-color: #ececef; border-radius: .25rem; margin-top: 0; font-family: "GitLab Mono","JetBrains Mono","Menlo","DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; vertical-align: bottom; white-space: pre-wrap; overflow-wrap: break-word; word-break: keep-all; padding: 2px 4px;'>if_options</code> structure is allocated memory when the options are read.</li>
<li style="line-height: 1.6em; margin-left: 25px; padding-left: 3px;">Options are assigned to interfaces.</li>
<li style="line-height: 1.6em; margin-left: 25px; padding-left: 3px;">The global <code style='font-size: 90%; color: #18171d; word-wrap: break-word; background-color: #ececef; border-radius: .25rem; margin-top: 0; font-family: "GitLab Mono","JetBrains Mono","Menlo","DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; vertical-align: bottom; white-space: pre-wrap; overflow-wrap: break-word; word-break: keep-all; padding: 2px 4px;'>if_options</code> variable is freed and set to <code style='font-size: 90%; color: #18171d; word-wrap: break-word; background-color: #ececef; border-radius: .25rem; font-family: "GitLab Mono","JetBrains Mono","Menlo","DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; vertical-align: bottom; white-space: pre-wrap; overflow-wrap: break-word; word-break: keep-all; padding: 2px 4px;'>NULL</code> before the event loop runs.</li>
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<p dir="auto" style="color: #28272d; margin: 0;" align="initial">My guess is the options pointer is being held in an interface (or somewhere else) and something related to the IP6 DHCP protocol handling updates an option setting in the <code style='font-size: 90%; color: #18171d; word-wrap: break-word; background-color: #ececef; border-radius: .25rem; margin-top: 0; font-weight: inherit; font-family: "GitLab Mono","JetBrains Mono","Menlo","DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; vertical-align: bottom; white-space: pre-wrap; overflow-wrap: break-word; word-break: keep-all; padding: 2px 4px;'>requiremask6</code> field. It could be related to the configuration of the DHCP server and an option given sets and option in <code style='font-size: 90%; color: #18171d; word-wrap: break-word; background-color: #ececef; border-radius: .25rem; font-weight: inherit; font-family: "GitLab Mono","JetBrains Mono","Menlo","DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; vertical-align: bottom; white-space: pre-wrap; overflow-wrap: break-word; word-break: keep-all; padding: 2px 4px;'>requiremask6</code> to <code style='font-size: 90%; color: #18171d; word-wrap: break-word; background-color: #ececef; border-radius: .25rem; font-weight: inherit; font-family: "GitLab Mono","JetBrains Mono","Menlo","DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; vertical-align: bottom; white-space: pre-wrap; overflow-wrap: break-word; word-break: keep-all; padding: 2px 4px;'>1</code>.</p>
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