Hello, Laura. On Wed, Dec 13, 2017 at 09:10:36AM -0800, Laura Abbott wrote: > On 12/13/2017 07:29 AM, Tejun Heo wrote: > >Hello, Laura. > > > >On Tue, Dec 12, 2017 at 04:38:33PM -0800, Laura Abbott wrote: > >>Hi, > >> > >>Fedora got a bug report on 4.14.4 of a crash on > >>reboot https://bugzilla.redhat.com/show_bug.cgi?id=1525279 > >> > >> BUG: unable to handle kernel NULL pointer dereference at 0000000000000254 > >> IP: __task_pid_nr_ns+0xc7/0xf0 > > > >Any chance you can map this back to the source line with addr2line? > > > >Thanks. > > > > annotated with decode_stacktrace.sh > > > IP: __task_pid_nr_ns > (/usr/src/debug/kernel-4.14.fc26/linux-4.14.4-200.fc26.x86_64/kernel/pid.c:506 > > /usr/src/debug/kernel-4.14.fc26/linux-4.14.4-200.fc26.x86_64/kernel/pid.c:535) Thank you very much for the trace. I *think* I found the place where the css task iterator points to a task without holding its ref allowing the task to go away before dereferenced. I'll update once I learn more.
Thanks. -- tejun
