BUG: scheduling while atomic

Running c application. Application used to work on RT kernel and uses SCHED_RR priority.
Now it crashes the moment it tries to create pthread threads that will run at some priortiy using SCHED_RR

'Full' crashreport from syslog:

Dec 17 16:32:02 host16 kernel: [ 1308.894129] BUG: scheduling while atomic: myapp/0x00000001/3340, CPU#0
Dec 17 16:32:02 host16 kernel: [ 1308.894132] Modules linked in: binfmt_misc vboxnetflt vboxnetadp vboxdrv nls_cp437 cifs snd_hda_codec_realtek snd_hda_intel snd_hda_codec snd_hwdep snd_pcm_oss snd_mixer_oss iptable_filter ip_tables x_tables snd_pcm snd_seq_dummy snd_seq_oss snd_seq_midi snd_rawmidi snd_seq_midi_event snd_seq snd_timer snd_seq_device snd ppdev lp parport_pc soundcore heci(C) snd_page_alloc parport led_class usbhid radeon ttm drm i2c_algo_bit e1000e floppy intel_agp
Dec 17 16:32:02 host16 kernel: [ 1308.894180] Pid: 3340, comm: myapp Tainted: G C 2.6.31-9-rt #152-Ubuntu
Dec 17 16:32:02 host16 kernel: [ 1308.894184] Call Trace:
Dec 17 16:32:02 host16 kernel: [ 1308.894189] [<ffffffff8104f92a>] __schedule_bug+0x6a/0x70
Dec 17 16:32:02 host16 kernel: [ 1308.894195] [<ffffffff8153bfb9>] thread_return+0x278/0x3cf
Dec 17 16:32:02 host16 kernel: [ 1308.894201] [<ffffffff8153c394>] schedule+0x14/0x30
Dec 17 16:32:02 host16 kernel: [ 1308.894206] [<ffffffff8153d41a>] rt_spin_lock_slowlock+0x1ba/0x290
Dec 17 16:32:02 host16 kernel: [ 1308.894213] [<ffffffff8153de46>] rt_spin_lock+0x36/0x60
Dec 17 16:32:02 host16 kernel: [ 1308.894218] [<ffffffff8153b807>] wait_for_common+0xc7/0x180
Dec 17 16:32:02 host16 kernel: [ 1308.894224] [<ffffffff8105a770>] ? default_wake_function+0x0/0x20
Dec 17 16:32:02 host16 kernel: [ 1308.894230] [<ffffffff8106f243>] ? signal_wake_up+0x43/0x50
Dec 17 16:32:02 host16 kernel: [ 1308.894236] [<ffffffff8153b958>] wait_for_completion+0x18/0x20
Dec 17 16:32:02 host16 kernel: [ 1308.894241] [<ffffffff81128fa4>] coredump_wait+0x1f4/0x230
Dec 17 16:32:02 host16 kernel: [ 1308.894247] [<ffffffff811298a6>] do_coredump+0x146/0x490
Dec 17 16:32:02 host16 kernel: [ 1308.894253] [<ffffffff8153bd94>] ? thread_return+0x53/0x3cf
Dec 17 16:32:02 host16 kernel: [ 1308.894259] [<ffffffff810774d9>] ? __task_pid_nr_ns+0x69/0xc0
Dec 17 16:32:02 host16 kernel: [ 1308.894265] [<ffffffff810717ea>] get_signal_to_deliver+0x19a/0x330
Dec 17 16:32:02 host16 kernel: [ 1308.894271] [<ffffffff81011a9d>] do_signal+0x8d/0x1f0
Dec 17 16:32:02 host16 kernel: [ 1308.894277] [<ffffffff8106e761>] ? sys_rt_sigaction+0x81/0xc0
Dec 17 16:32:02 host16 kernel: [ 1308.894283] [<ffffffff81011c4f>] do_notify_resume+0x4f/0x60
Dec 17 16:32:02 host16 kernel: [ 1308.894288] [<ffffffff81012c1c>] retint_signal+0x48/0x8c
Dec 17 16:32:02 host16 kernel: [ 1308.894311] note: myapp[3340] exited with preempt_count 1

Running Karmic 9.10 AMD64 on Intel processor with all recent patches.

Excerpt of c code (-m64):

 pthread_t my_thread;

    struct sched_param param;
    pthread_attr_t threadAttr;

    param.sched_priority = 2;
    if (sched_setscheduler(0, SCHED_RR, &param) != 0) {
        exit(-1);
    }

    param.sched_priority = 90;
    pthread_attr_init(&threadAttr);
    pthread_attr_setschedpolicy(&threadAttr, SCHED_RR);
    pthread_attr_setschedparam(&threadAttr, &param);

    if (pthread_create(&my_thread, &threadAttr, my_task, (void *) 10) != 0) {
        exit(-1);
    }
    pthread_attr_destroy(&threadAttr);

ProblemType: Bug
Architecture: amd64
Date: Mon Dec 21 13:44:10 2009
DistroRelease: Ubuntu 9.10
InstallationMedia: Ubuntu 9.10 "Karmic Koala" - Release amd64 (20091027)
Package: linux-image-2.6.31-9-rt 2.6.31-9.152
ProcEnviron:
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.31-16.53-generic
SourcePackage: linux-rt
Uname: Linux 2.6.31-16-generic x86_64