From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paul_Woegerer@mentor.com (Woegerer, Paul) Date: Fri, 28 Feb 2014 10:33:07 +0100 Subject: [lttng-dev] baddr feature triggers deadlock in lttng-ust In-Reply-To: <561294755.31915.1393536606539.JavaMail.zimbra@efficios.com> References: <561294755.31915.1393536606539.JavaMail.zimbra@efficios.com> Message-ID: <531057D3.1070607@mentor.com> Hi Mathieu, this is very unfortunate. I tested forks as well but couldn?t find any issues on x86_64. Ironically, last week we found an issue that matches your description on PowerPC but since we could not reproduce it on x86 I blamed it on the peculiarities of that platform and worked on seemingly higher priority issues instead. For the sake of damage containment I just posted: http://lists.lttng.org/pipermail/lttng-dev/2014-February/022494.html to the list. Not having that feature in 2.4 (at least in the experimental form suggested above) would be a disaster for us. Meanwhile I'm trying to think about a more fundamental solution to the problem. But I'm afraid your comment about rethinking of the locking strategy for the entire UST might come true. Thanks, Paul On 02/27/2014 10:30 PM, Mathieu Desnoyers wrote: > Hi Paul, > > Please see http://bugs.lttng.org/issues/745, which explains a deadlock > we just found out. > > We might have to disable the baddr dump feature, since our release is > tomorrow. We'll have to re-think our locking to protect operations > using the dynamic loader lock against fork, clone, and daemon. > > Thanks, > > Mathieu > -- Paul Woegerer, SW Development Engineer Sourcery Analyzer Mentor Graphics, Embedded Software Division