Re: [libvirt] [PATCH] virlog: Add stack trace log when libvirt receives fatal signal

> -----Original Message----- > From: Daniel P. Berrange [mailto:berrange@redhat.com] > Sent: Tuesday, May 20, 2014 5:05 PM > To: Wangrui (K) > Cc: libvir-list(a)redhat.com; zhouyimin Zhou(Yimin); Yanqiangjun > Subject: Re: [PATCH] virlog: Add stack trace log when libvirt receives fatal signal > > On Tue, May 20, 2014 at 08:59:37AM +0000, Wangrui (K) wrote: > > An earlier commit(c0c8c1) Dan removed global log buffer feature entirely > > because of duplicate log messages. An improvement is introduced. That is > > dumping stack trace instead of log buffer upon libvirt crash. > > > This is not going to work. virLogStackTraceToFd invokes the > backtrace/backtrace_symbols_fd functions which are not async > signal safe. They are also not likely to be reliable to use > when you have memory corruption triggering the signal. > > The 'abrt' program is commonly used on modern Linux distros to > generate stack traces when processes crash / terminate abnormally. > abrt has the added benefit that the stack traces it records include > all function parameters and local variables. > Oops. I didn't realize Async-signal-(un)safe functions in virLogStackTraceToFd. And it seems that only kernel coredump can be used in this case. My original purpose is to trace stack on crash/obort and etc without using kernel.core_pattern (sometimes kernel coredump is not turned on ).

Thanks. > Regards, > Daniel > -- > |: http://berrange.com -o- > http://www.flickr.com/photos/dberrange/ :| > |: http://libvirt.org -o- > http://virt-manager.org :| > |: http://autobuild.org -o- > http://search.cpan.org/~danberr/ :| > |: http://entangle-photo.org -o- > http://live.gnome.org/gtk-vnc :|