K 10
svn:author
V 3
mav
K 8
svn:date
V 27
2015-10-05T08:13:29.947236Z
K 7
svn:log
V 874
MFC r271731 (by will): Fix a kernel panic when unloading isp(4).

In the current implementation, the isp_kthread() threads never exit.

The target threads do have an exit mode from isp_attach(), but it is
not invoked from isp_detach().

Ensure isp_detach() notifies threads started for each channel, such
that they exit before their parent device softc detaches, and thus
before the module does.  Otherwise, a page fault panic occurs later in:

sysctl_kern_proc
  sysctl_out_proc
    kern_proc_out
      fill_kinfo_proc
        fill_kinfo_thread
          strlcpy(kp->ki_wmesg, td->td_wmesg, sizeof(kp->ki_wmesg));

For isp_kthread() (and isp(4) target threads), td->td_wmesg references
now-unmapped memory after the module has been unloaded.  These threads
are typically msleep()ing at the time of unload, but they could also
attempt to execute now-unmapped code segments.

END