BBB UART4 MODEM SIM928

beaglebone login: [59740.036843] BUG: soft lockup - CPU#0 stuck for 21s! [kworke                                                                                                                               r/0:1:31134]
[59740.044186] BUG: scheduling while atomic: kworker/0:1/31134/0x40010100
[59740.052564] Kernel panic - not syncing: softlockup: hung tasks
[59740.058656] [<c001125d>] (unwind_backtrace+0x1/0x98) from [<c049d293>] (panic                                                                                                                               +0x5b/0x160)
[59740.067196] [<c049d293>] (panic+0x5b/0x160) from [<c00726c9>] (watchdog_timer                                                                                                                               _fn+0xed/0x10c)
[59740.076010] [<c00726c9>] (watchdog_timer_fn+0xed/0x10c) from [<c00472a1>] (__                                                                                                                               run_hrtimer+0x49/0x128)
[59740.085548] [<c00472a1>] (__run_hrtimer+0x49/0x128) from [<c0047acf>] (hrtime                                                                                                                               r_interrupt+0xcb/0x200)
[59740.095083] [<c0047acf>] (hrtimer_interrupt+0xcb/0x200) from [<c001ea95>] (om                                                                                                                               ap2_gp_timer_interrupt+0x1d/0x20)
[59740.105529] [<c001ea95>] (omap2_gp_timer_interrupt+0x1d/0x20) from [<c0072d8b                                                                                                                               >] (handle_irq_event_percpu+0x37/0x178)
[59740.116512] [<c0072d8b>] (handle_irq_event_percpu+0x37/0x178) from [<c0072ef5                                                                                                                               >] (handle_irq_event+0x29/0x3c)
[59740.126769] [<c0072ef5>] (handle_irq_event+0x29/0x3c) from [<c007481f>] (hand                                                                                                                               le_level_irq+0x53/0x8c)
[59740.136310] [<c007481f>] (handle_level_irq+0x53/0x8c) from [<c00729cb>] (gene                                                                                                                               ric_handle_irq+0x13/0x1c)
[59740.146021] [<c00729cb>] (generic_handle_irq+0x13/0x1c) from [<c000cfdb>] (ha                                                                                                                               ndle_IRQ+0x23/0x60)
[59740.155197] [<c000cfdb>] (handle_IRQ+0x23/0x60) from [<c00085d9>] (omap3_intc                                                                                                                               _handle_irq+0x5d/0x68)
[59740.164633] [<c00085d9>] (omap3_intc_handle_irq+0x5d/0x68) from [<c04a301b>]                                                                                                                                (__irq_svc+0x3b/0x5c)
[59740.173978] Exception stack(0xdf7d1ce0 to 0xdf7d1d28)
[59740.179247] 1ce0: 00000000 00000023 000000b2 fa1cc0b2 df2d4540 00008000 00000                                                                                                                               022 c0864624
[59740.187783] 1d00: c0d27608 00000010 c0d27600 0000012c df7c7b20 df7d1d28 bf96f                                                                                                                               019 bf975010
[59740.196310] 1d20: 80000133 ffffffff
[59740.199955] [<c04a301b>] (__irq_svc+0x3b/0x5c) from [<bf975010>] (c_can_plat_                                                                                                                               read_reg_aligned_to_16bit+0xf/0x18 [c_can_platform])
[59740.212114] [<bf975010>] (c_can_plat_read_reg_aligned_to_16bit+0xf/0x18 [c_ca                                                                                                                               n_platform]) from [<bf96f019>] (c_can_read_reg32+0x18/0x20 [c_can])
[59740.225624] [<bf96f019>] (c_can_read_reg32+0x18/0x20 [c_can]) from [<bf96f99f                                                                                                                               >] (c_can_poll+0x26a/0x59c [c_can])
[59740.236250] [<bf96f99f>] (c_can_poll+0x26a/0x59c [c_can]) from [<c03fb0fd>] (                                                                                                                               net_rx_action+0x65/0x128)
[59740.245964] [<c03fb0fd>] (net_rx_action+0x65/0x128) from [<c00349eb>] (__do_s                                                                                                                               oftirq+0xab/0x184)
[59740.255042] [<c00349eb>] (__do_softirq+0xab/0x184) from [<c0034cbd>] (irq_exi                                                                                                                               t+0x51/0x58)
[59740.263567] [<c0034cbd>] (irq_exit+0x51/0x58) from [<c000cfdf>] (handle_IRQ+0                                                                                                                               x27/0x60)
[59740.271822] [<c000cfdf>] (handle_IRQ+0x27/0x60) from [<c00085d9>] (omap3_intc                                                                                                                               _handle_irq+0x5d/0x68)
[59740.281267] [<c00085d9>] (omap3_intc_handle_irq+0x5d/0x68) from [<c04a301b>]                                                                                                                                (__irq_svc+0x3b/0x5c)
[59740.290618] Exception stack(0xdf7d1e30 to 0xdf7d1e78)
[59740.295886] 1e20:                                     de3bc024 a0000013 00000                                                                                                                               000 53595359
[59740.304416] 1e40: a0000013 df7d710b 00000011 00000001 de3bc000 df7d720b c04da                                                                                                                               390 de65982e
[59740.312953] 1e60: 000000ea df7d1e78 c04a2d81 c04a2d84 60000033 ffffffff
[59740.319860] [<c04a301b>] (__irq_svc+0x3b/0x5c) from [<c04a2d84>] (_raw_spin_u                                                                                                                               nlock_irqrestore+0xc/0x10)
[59740.329655] [<c04a2d84>] (_raw_spin_unlock_irqrestore+0xc/0x10) from [<bf98a2                                                                                                                               d5>] (ppp_asynctty_receive+0x148/0x394 [ppp_async])
[59740.341728] [<bf98a2d5>] (ppp_asynctty_receive+0x148/0x394 [ppp_async]) from                                                                                                                                [<c02746a5>] (flush_to_ldisc+0xe9/0xf8)
[59740.352715] [<c02746a5>] (flush_to_ldisc+0xe9/0xf8) from [<c0041647>] (proces                                                                                                                               s_one_work+0xd7/0x310)
[59740.362161] [<c0041647>] (process_one_work+0xd7/0x310) from [<c0041ad3>] (wor                                                                                                                               ker_thread+0x107/0x328)
[59740.371687] [<c0041ad3>] (worker_thread+0x107/0x328) from [<c004480f>] (kthre                                                                                                                               ad+0x6b/0x74)
[59740.380306] [<c004480f>] (kthread+0x6b/0x74) from [<c000c7fd>] (ret_from_fork                                                                                                                               +0x11/0x34)