Norbert van Bolhuis <nvbolh...@aimvalley.nl> wrote on 2010/11/09 10:47:46: > > Joakim Tjernlund wrote: > >>> I can't make out what is causing this hang every now an then: > >>> > >>> INFO: task snmpd:398 blocked for more than 120 seconds. > >> My problem with that 'error' message is that there is no way > >> for a driver to disable it on a per-process basis. > >> We have some processes whose 'normal state' is to sleep > >> uninterruptibly in the kernel. Shutdown is handled by > >> an explicit request (not by sending a signal). > >> The processes could be kernel worker threads (except that > >> is is ~impossible to handle them exiting from a loadble > >> kernel module) so are actually children of a daemon sat > >> inside an ioctl() request that never terminates! > >> > >> However, on the face of it, your case does look as though > >> the mutex is fubar'ed. > >> > >> Might be worth (somehow) dumping the mutex state. > > > > ehh, it is locked, isn't it? How to find who locked it > > and forgot to release it? > > > > You could add show_state to check_hung_task > > It worked for me while solving some (application) task hangups.
Will have a look at that too, thanks. Meanwhile i have tried to turn on various LOCK debug and that results in an unbootable kernel. Somewhere the dev. tree. gets mangled and it happens when DEBUG_LOCK_ALLOC is set. Don't know why and I must move on. Someone else might want to try if DEBUG_LOCK_ALLOC works on embedded ppc boards, especially 83xx. Jocke _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev