{"id":4857,"date":"2018-11-06T17:45:14","date_gmt":"2018-11-06T16:45:14","guid":{"rendered":"https:\/\/monodes.com\/predaelli\/?p=4857"},"modified":"2018-11-06T15:02:19","modified_gmt":"2018-11-06T14:02:19","slug":"bug-chasing","status":"publish","type":"post","link":"https:\/\/monodes.com\/predaelli\/2018\/11\/06\/bug-chasing\/","title":{"rendered":"Bug chasing"},"content":{"rendered":"<p>Some months ago I&#8217;ve set up a Debian 9 virtual machine on the VMWare server of the <a href=\"https:\/\/en.wikipedia.org\/wiki\/Small_and_medium-sized_enterprises\">SME<\/a> I work for. I planned to enable several services on it:<\/p>\n<ul>\n<li>an IMAP server to locally store the email archive of the administration office<\/li>\n<li>a shared calendar and address-book with the startd protocols CalDAV and CardDAV; while there are leaner server for those I chose to install <a href=\"https:\/\/nextcloud.com\/\">Nextcloud<\/a> as it would be far easier to use and integrate.<\/li>\n<\/ul>\n<p>I picked Debian 9 as the operative system as it allows for a leaner and lighter installation when you start from its netinstall version. Knowing that the 40Gb I provisioned for 4 users will surely require to be expanded&nbsp; sometime in the future I used <a href=\"http:\/\/sources.redhat.com\/lvm2\/\">Logical Volume Manager<\/a>.<\/p>\n<p>Everything looked fine and ran smoothly for some weeks then I started to find the machine hanged.<\/p>\n<p>As I&#8217;m the only full-time employee with some proficiency in IT I am the de-facto help desk for anything &#8220;computer related&#8221;: remote banking issues, updating Java on Windows 10, maintaining installed the latest Firefox version that still support the Java Applets required by the remote banking, handling anti-viruses, non-administrative applications updates and so on. All this listing to say that I have root access on the VMWare console. I needed to reset this VM (called <code class=\"\" data-line=\"\">posta<\/code>)<\/p>\n<p>I had to <a href=\"https:\/\/unix.stackexchange.com\/questions\/8056\/disable-screen-blanking-on-text-console#32043\">Disable screen blanking on text console (thanks, Stack Exchange!)<\/a> to catch the bug as I just can&#8217;t stare at a console for several hours hoping to catch it. So, after having removed the timeouts I left the console opened for a while.<\/p>\n<p>I hadn&#8217;t to wait too long. The day after I&#8217;ve finally got a clue to follow :<\/p>\n\n\n<figure class=\"wp-block-image\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"910\" height=\"512\" data-attachment-id=\"4861\" data-permalink=\"https:\/\/monodes.com\/predaelli\/2018\/11\/06\/bug-chasing\/vmxnet3-bug\/\" data-orig-file=\"https:\/\/i0.wp.com\/monodes.com\/predaelli\/wp-content\/uploads\/sites\/4\/2018\/11\/vmxnet3-bug.png?fit=1920%2C1080&amp;ssl=1\" data-orig-size=\"1920,1080\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"vmxnet3-bug\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/i0.wp.com\/monodes.com\/predaelli\/wp-content\/uploads\/sites\/4\/2018\/11\/vmxnet3-bug.png?fit=300%2C169&amp;ssl=1\" data-large-file=\"https:\/\/i0.wp.com\/monodes.com\/predaelli\/wp-content\/uploads\/sites\/4\/2018\/11\/vmxnet3-bug.png?fit=510%2C287&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/monodes.com\/predaelli\/wp-content\/uploads\/sites\/4\/2018\/11\/vmxnet3-bug.png?resize=910%2C512&#038;ssl=1\" alt=\"\" class=\"wp-image-4861\" srcset=\"https:\/\/i0.wp.com\/monodes.com\/predaelli\/wp-content\/uploads\/sites\/4\/2018\/11\/vmxnet3-bug.png?w=1920&amp;ssl=1 1920w, https:\/\/i0.wp.com\/monodes.com\/predaelli\/wp-content\/uploads\/sites\/4\/2018\/11\/vmxnet3-bug.png?resize=300%2C169&amp;ssl=1 300w, https:\/\/i0.wp.com\/monodes.com\/predaelli\/wp-content\/uploads\/sites\/4\/2018\/11\/vmxnet3-bug.png?resize=768%2C432&amp;ssl=1 768w, https:\/\/i0.wp.com\/monodes.com\/predaelli\/wp-content\/uploads\/sites\/4\/2018\/11\/vmxnet3-bug.png?resize=510%2C287&amp;ssl=1 510w, https:\/\/i0.wp.com\/monodes.com\/predaelli\/wp-content\/uploads\/sites\/4\/2018\/11\/vmxnet3-bug.png?w=1820&amp;ssl=1 1820w\" sizes=\"auto, (max-width: 910px) 100vw, 910px\" \/><figcaption>Oh it looks I&#8217;ve found a bug in a kernel driver<\/figcaption><\/figure>\n\n\n\n<p>Finally <a href=\"https:\/\/duckduckgo.com\/?q=vmxnet3_rq_rx_complete+&amp;t=ffab&amp;ia=web\">something to look for<\/a>: the bug is in the kernel driver<code class=\"\" data-line=\"\">&nbsp;vmxnet3_rq_rx_complete<\/code>. Luckily it seems a fairly common bug; excluding the bug reports from RedHat that are &#8211; rightly so! &#8211; available only to the subscribers of their services there is an interesting bug report in VMWare Knoledge Base titled \u00ab<a href=\"https:\/\/kb.vmware.com\/s\/article\/2151480\">Linux VM fails with the error &#8220;kernel BUG at drivers\/net\/vmxnet3\/vmxnet3_drv.c:1413!&#8221; (2151480)<\/a>\u00bb. <\/p>\n\n\n\n<p>As the VMWare also runs the main administrative applications I think it wasn&#8217;t worth a call to the remote management so I&#8217;ve applied the workaround on <code class=\"\" data-line=\"\">posta<\/code>. <\/p>\n\n\n\n<p>As this bug showed somehow randomly I can only leave the console open and keep an eye on it.<\/p>\n\n\n\n<p>I&#8217;ll let you know if it worked.<br \/><\/p>\n\n\n\n<p><a href=\"https:\/\/unix.stackexchange.com\/questions\/8056\/disable-screen-blanking-on-text-console#32043\"> <br \/><\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p class=\"excerpt\">Some months ago I&#8217;ve set up a Debian 9 virtual machine on the VMWare server of the SME I work for. I planned to enable several services on it: an IMAP server to locally store the email archive of the administration office a shared calendar and address-book with the startd protocols CalDAV and CardDAV; while&hellip;<\/p>\n<p class=\"more-link-p\"><a class=\"more-link\" href=\"https:\/\/monodes.com\/predaelli\/2018\/11\/06\/bug-chasing\/\">Read more &rarr;<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"inline_featured_image":false,"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"activitypub_content_warning":"","activitypub_content_visibility":"","activitypub_max_image_attachments":4,"activitypub_interaction_policy_quote":"anyone","activitypub_status":"","footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[72,13],"tags":[],"class_list":["post-4857","post","type-post","status-publish","format-standard","hentry","category-documentations","category-gnulinux"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p6daft-1gl","jetpack-related-posts":[{"id":1789,"url":"https:\/\/monodes.com\/predaelli\/2016\/09\/28\/joining-debian-8-to-active-directory\/","url_meta":{"origin":4857,"position":0},"title":"Joining Debian 8 to Active Directory","author":"Paolo Redaelli","date":"2016-09-28","format":"link","excerpt":"Joining Debian 8 to Active Directory Joining a GNU\/Linux machine to a Microsoft Active Directory has been possible for years, but it\u2019s always been a bit of a science project that involved touching half-a-dozen obscure config files and usually resulted in me getting completely locked out of the machine. Various\u2026","rel":"","context":"In &quot;Documentations&quot;","block_context":{"text":"Documentations","link":"https:\/\/monodes.com\/predaelli\/category\/documentations\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":3717,"url":"https:\/\/monodes.com\/predaelli\/2018\/01\/28\/how-to-install-skype-for-linux-beta-on-debian-9-stretch-linuxbabe-com\/","url_meta":{"origin":4857,"position":1},"title":"How to Install Skype for Linux Beta on Debian 9 Stretch &#8211; LinuxBabe.Com","author":"Paolo Redaelli","date":"2018-01-28","format":false,"excerpt":"How to Install Skype for Linux Beta on Debian 9 Stretch - LinuxBabe.Com Skype for Linux beta 5.3 was released on May 31, 2017. It is a proprietary software, built on the web-based Skype client. This tutorial is going to show you how to install Skype on Debian 9 Stretch\u2026","rel":"","context":"In &quot;Debian&quot;","block_context":{"text":"Debian","link":"https:\/\/monodes.com\/predaelli\/category\/debian\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":9126,"url":"https:\/\/monodes.com\/predaelli\/2022\/03\/02\/how-to-install-yunohost-on-debian-10\/","url_meta":{"origin":4857,"position":2},"title":"How To Install Yunohost on Debian 10","author":"Paolo Redaelli","date":"2022-03-02","format":"status","excerpt":"I just don't want to erase my Raspbian installation on my \"aging\" Raspberry Pi 3, I think I will follow this guide: How To Install Yunohost on Debian 10. After all \/etc\/debian_version says it is a bullseye\/sid...","rel":"","context":"In &quot;Senza categoria&quot;","block_context":{"text":"Senza categoria","link":"https:\/\/monodes.com\/predaelli\/category\/senza-categoria\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":1648,"url":"https:\/\/monodes.com\/predaelli\/2016\/06\/07\/debianisms\/","url_meta":{"origin":4857,"position":3},"title":"Debianisms","author":"Paolo Redaelli","date":"2016-06-07","format":false,"excerpt":"I was going to enable mod_rewrite on the new work box, discovering that CentOS doesn't have a2enmod. So reading apache 2.2 - CentOS\u201c-bash: a2enmod: command not found\u201d - from Server Fault I discovered that a2enmod is a debianism, on CentOS you will need to do this manually. Please refer to\u2026","rel":"","context":"In &quot;Fedora - RedHat&quot;","block_context":{"text":"Fedora - RedHat","link":"https:\/\/monodes.com\/predaelli\/category\/fedora-redhat\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":4603,"url":"https:\/\/monodes.com\/predaelli\/2018\/10\/01\/spheres-can-make-concrete-leaner-greener\/","url_meta":{"origin":4857,"position":4},"title":"Spheres can make concrete leaner, greener","author":"Paolo Redaelli","date":"2018-10-01","format":"link","excerpt":"Rice University scientists have developed micron-sized calcium silicate spheres that could lead to stronger and greener concrete, the world's most-used synthetic material. Sorgente: Spheres can make concrete leaner, greener","rel":"","context":"In &quot;Senza categoria&quot;","block_context":{"text":"Senza categoria","link":"https:\/\/monodes.com\/predaelli\/category\/senza-categoria\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":10220,"url":"https:\/\/monodes.com\/predaelli\/2023\/02\/06\/firmware-debian-wiki\/","url_meta":{"origin":4857,"position":5},"title":"Firmware &#8211; Debian Wiki","author":"Paolo Redaelli","date":"2023-02-06","format":false,"excerpt":"The Debian project has taken the decision in 2022-10 to create a new repository component non-free-firmware, and include its content on installation media for the upcoming Debian release bookworm to make things easier for our users. From Firmware - Debian Wiki So people like me that installed Debian several years\u2026","rel":"","context":"In &quot;Debian&quot;","block_context":{"text":"Debian","link":"https:\/\/monodes.com\/predaelli\/category\/debian\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]}],"jetpack_likes_enabled":true,"_links":{"self":[{"href":"https:\/\/monodes.com\/predaelli\/wp-json\/wp\/v2\/posts\/4857","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/monodes.com\/predaelli\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/monodes.com\/predaelli\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/monodes.com\/predaelli\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/monodes.com\/predaelli\/wp-json\/wp\/v2\/comments?post=4857"}],"version-history":[{"count":0,"href":"https:\/\/monodes.com\/predaelli\/wp-json\/wp\/v2\/posts\/4857\/revisions"}],"wp:attachment":[{"href":"https:\/\/monodes.com\/predaelli\/wp-json\/wp\/v2\/media?parent=4857"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/monodes.com\/predaelli\/wp-json\/wp\/v2\/categories?post=4857"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/monodes.com\/predaelli\/wp-json\/wp\/v2\/tags?post=4857"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}