do_IRQ: stack overflow: 60

Call Trace:

 [<02107263>] do_IRQ+0x45/0x169

 [<0213007b>] read_cache_pages+0x67/0xdf

 [<22b1cbb0>] zt_common_ioctl+0x9b0/0xb70 [zaptel]

 [<02135342>] follow_page+0xda/0xe5

 [<0213f1ba>] rw_vm+0x1ce/0x1ea

 [<0213f423>] put_user_size+0x29/0x2d

 [<02135342>] follow_page+0xda/0xe5

 [<0213f1ba>] rw_vm+0x1ce/0x1ea

 [<0213f3d3>] get_user_size+0x30/0x57

 [<22b197ba>] zt_chanandpseudo_ioctl+0x8a/0x13c0 [zaptel]

 [<02115617>] recalc_task_prio+0x141/0x14c

 [<02115ed2>] __wake_up_common+0x2f/0x50

 [<02115f01>] __wake_up+0xe/0x16

 [<02115ed2>] __wake_up_common+0x2f/0x50

 [<02115f01>] __wake_up+0xe/0x16

 [<021bef98>] n_tty_receive_buf+0x972/0x9a1

 [<0212e95c>] buffered_rmqueue+0x124/0x147

 [<02135342>] follow_page+0xda/0xe5

 [<021c0605>] pty_write+0x103/0x110

 [<021be15b>] opost_block+0x146/0x153

 [<22b1ab67>] zt_chan_ioctl+0x77/0xae0 [zaptel]

 [<0214af24>] do_lookup+0x18/0x72

 [<021479f9>] chrdev_open+0xfa/0x127

 [<02140a6a>] dentry_open+0xc2/0x171

 [<22b170fa>] zt_ioctl+0x5a/0x100 [zaptel]

 [<0214ea0e>] sys_ioctl+0x1f2/0x224

 [<0211a916>] sys_time+0x12/0x3d