{"id":19122,"date":"2025-08-29T14:28:30","date_gmt":"2025-08-29T14:28:30","guid":{"rendered":"http:\/\/www.max-sperling.bplaced.net\/?p=19122"},"modified":"2025-09-01T08:30:15","modified_gmt":"2025-09-01T08:30:15","slug":"example-of-a-found-hw-issues","status":"publish","type":"post","link":"http:\/\/www.max-sperling.bplaced.net\/?p=19122","title":{"rendered":"Example of a found HW issue"},"content":{"rendered":"<h2>Coredump<\/h2>\n<pre class=\"brush: plain; gutter: false; title: ; notranslate\" title=\"\">\r\nProgram terminated with signal SIGSEGV, Segmentation fault.\r\n#0  0x00007fcc4ba55d7e in ...\r\n(gdb) p $_siginfo._sifields._sigfault.si_addr\r\n$1 = (void *) 0x7fcd00000003\r\n(gdb) x\/i $pc\r\n=&gt; 0x7fcc4ba55d7e &lt;...&gt;: mov    0x4(%r8),%r8d\r\n(gdb) p\/x *(uint64_t*)($r8 + 0x4)\r\n$2 = 0x7fccffffffff\r\n(gdb) p\/x $r8 + 4\r\n$3 = 0x7fcd00000003\r\n(gdb) disas\r\n...\r\n   0x00007fcc4ba55d7a &lt;+74&gt;:  mov    0x10(%rcx),%r8\r\n=&gt; 0x00007fcc4ba55d7e &lt;+78&gt;:   mov    0x4(%r8),%r8d\r\n(gdb) p\/x *(uint64_t*)($rcx + 0x10)\r\n$4 = 0x7fcc20438f1c\r\n<\/pre>\n<hr>\n<h2>Reasoning<\/h2>\n<ol>\n<li>It fails to get the value at &#8220;0x4(%r8)&#8221;, because it&#8217;s outside the own memory segments.<\/li>\n<li>The value of R8 looks already very suspicious: 0x7fccffffffff.<\/li>\n<li>&#8220;p\/x *(uint64_t*)($rcx + 0x10)&#8221; should have the same value as &#8220;p\/x $r8&#8221;.<\/li>\n<li>It seems to be an issue of the CPU itself.<\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"<p>Coredump Reasoning It fails to get the value at &#8220;0x4(%r8)&#8221;, because it&#8217;s outside the own memory segments. The value of<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"inline_featured_image":false},"categories":[28],"tags":[],"_links":{"self":[{"href":"http:\/\/www.max-sperling.bplaced.net\/index.php?rest_route=\/wp\/v2\/posts\/19122"}],"collection":[{"href":"http:\/\/www.max-sperling.bplaced.net\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.max-sperling.bplaced.net\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.max-sperling.bplaced.net\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.max-sperling.bplaced.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=19122"}],"version-history":[{"count":9,"href":"http:\/\/www.max-sperling.bplaced.net\/index.php?rest_route=\/wp\/v2\/posts\/19122\/revisions"}],"predecessor-version":[{"id":19149,"href":"http:\/\/www.max-sperling.bplaced.net\/index.php?rest_route=\/wp\/v2\/posts\/19122\/revisions\/19149"}],"wp:attachment":[{"href":"http:\/\/www.max-sperling.bplaced.net\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=19122"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.max-sperling.bplaced.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=19122"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.max-sperling.bplaced.net\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=19122"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}