The "scheduling while atomic" should be happening in this case because a
panic happens in atomic context, and the panic calls its notifier list
which contains drm_fb_helper_panic (the switch to console on modesetting
framebuffer).

drm_fb_helper_panic calls
drm_fb_helper_force_kernel_mode->drm_crtc_helper_set_config

drm_crtc_helper_set_config has kzalloc calls with GFP_KERNEL, which
means it has __GFP_WAIT set. This makes it the allocation routines call
might_sleep, which calls _cond_resched and may be schedule()... in this
case schedule was called so you get this trace.

One fix to this would be turning the kzalloc calls to use GFP_ATOMIC
instead, so we avoid kzalloc calling schedule. Anyway, this is not the
regression reported here, just this scheduling while atomic makes it
harder to see the real problem (the panic that should scrolled up on the
screen).

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https://bugs.launchpad.net/bugs/793796

Title:
  2.6.38-10 panic after ejecting drive

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