Could you add the http link you have visited when FF crashed? Maybe someone can reproduce it.
Does your FF also crash with apparmor profile disabled? My experience is that FF tolerates a lot of these apparmor-blocked actions which are reported in syslog. These logged errors are not necessarily the reason why FF crashed. But could, of course. In your case, I would also check the system memory with mem86. Let it run during a weekend and see what happens. -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to firefox in Ubuntu. https://bugs.launchpad.net/bugs/1656065 Title: Firefox and plugin-container (Chrome_ChildThr): segfault at 0 ip b76df673 sp b1efe9f0 error 6 in plugin-container/libxul.so Status in firefox package in Ubuntu: Confirmed Bug description: Hello. Some days ago, Firefox unexpectedly has been closed after a couple of hours (mostly viewed: YouTube and some other websites). Next, a dialog box related to the Mozilla Crash Reporter appeared - with message, that reporter is disabled (which I did earlier via 'about:config' and *datareporting.healthreport.service.enabled* key set to _false_) and no crash report is available even via 'about:crashes' etc. After this situation two entries appeared in the log files: first related to the AppArmor and second: plugin-container segfault. By the way: in the same time there was an update for flash-plugin available (see: 1). Anyway, 'LastCrash' file (which can be found in ~/.mozilla/firefox/Crash Reports/ directory) contains only: 1484142985. Just like all the others files in this directory. There are also two folders called: 'events' and 'pending'. But they are completely empty. However, system log files, such as '/var/log/kern.log' or '/var/log/syslog', contains an interesting entries: ● Jan 11 14:56:25 t4 kernel: [ 4161.295639] type=1400 audit(1484142985.517:46): apparmor="DENIED" operation="open" parent=2818 profile="/usr/lib/firefox/firefox{,*[^s][^h]}" name="/proc/2818/task/" pid=3253 comm="firefox" requested_mask="r" denied_mask="r" fsuid=1000 ouid=1000 ● Jan 11 14:56:25 t4 kernel: [ 4161.540727] Chrome_ChildThr[2890]: segfault at 0 ip b76df673 sp b1efe9f0 error 6 in plugin- container[b76d8000+42000] As we know, thanks to the plugin-container, plugins are separated from the browser process, making it more stable, right? So now if a plugin crashes, Firefox should remains unharmed. It looks like this is a known problem (see: 2, 3). By the way; on Moday, 16 January, Firefox has been closed again - no action from my side. Log files contain the same entries as above: ● Jan 16 16:39:35 t4 kernel: [14373.711834] type=1400 audit(1484581175.931:48): apparmor="DENIED" operation="open" parent=2532 profile="/usr/lib/firefox/firefox{,*[^s][^h]}" name="/proc/2532/task/" pid=3389 comm="firefox" requested_mask="r" denied_mask="r" fsuid=1000 ouid=1000 ● Jan 16 16:39:36 t4 kernel: [14373.934394] Chrome_ChildThr[3041]: segfault at 0 ip b76f8673 sp b1efe9f0 error 6 in plugin- container[b76f1000+42000] Anyway, after adding these two rules to the Firefox profile, everything seems to be OK and there is not DENIED message for "/proc/*/task/" entry anymore (so the first issue is solved): owner @{PROC}/[0-9]*/task/ r, owner @{PROC}/[0-9]*/task/* r, NOTE: This problem occurs when adobe-flash plugin is not activated and is permanently disabled and also when is used/enabled. Here are some informations about versions etc.: ● Firefox: 50.1.0 ● Flash: 24.0.0.194ubuntu0.12.04.1 ● Linux: 3.2.0-120-generic-pae (3.2.79) i686 ● AppArmor: 2.7.102-0ubuntu3.10 ● Release: 12.04.5 LTS (via `lsb_release -a` command) Best regards. _____________ [1] https://lists.ubuntu.com/archives/precise-changes/2017-January/026047.html [2] https://bugzilla.mozilla.org/show_bug.cgi?id=1205199 [3] https://bugzilla.redhat.com/show_bug.cgi?id=1253086 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/firefox/+bug/1656065/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp

