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Orbi RBR40 kernel panics
My Orbi RBR40 randomly reboots several times a day. The debug logs indicate that this is caused by a kernel panic:
<0>Kernel panic - not syncing: Fatal exception in interrupt <4>@@@@@@@@@ DNI Kernel panic @@@@@@@@@@ 3 <0>3ea0: b6f5e000 00100073 00000000 dcabc600 00000000 dcb59ba8 00000001 00000001
5 Replies
What is the Mfr and model# of the ISP modem the NG router is connected too?
Do you have RBS connected? Wireless or wired?
someuser2 wrote:My Orbi RBR40 randomly reboots several times a day. The debug logs indicate that this is caused by a kernel panic:
<0>Kernel panic - not syncing: Fatal exception in interrupt <4>@@@@@@@@@ DNI Kernel panic @@@@@@@@@@ 3 <0>3ea0: b6f5e000 00100073 00000000 dcabc600 00000000 dcb59ba8 00000001 00000001
It is attached to a Surfboard 6141 modem. I tried a factory reset, but it did not make a difference. The panic occurs in a function related to neighbor advertisements (ecm_interface_send_neighbour_solicitation), so I tried disabling IPv6 a week ago - no reboot since (though this is just a workaround, of course; you'd expect a modern router to properly support IPv6). The panic log indicates that an alignment exception occurs when executing a LDREX instruction; I believe this occurs in atomic_dec_and_test in neigh_release (which is inlined in ecm_interface_send_neighbour_solicitation; this atomically decrements the reference count in the neighbour struct). I am not too familiar with ARMv7; does LDREX require a page-aligned pointer? If so, I think this is the cause - the refcnt member in struct neighbour is at offset 0x18, which isn't page-aligned. I can provide a full panic log for your engineers to look at.
As suggested, please contact NG support and let them know whats is going on. Ask about an RMA.
someuser2 wrote:It is attached to a Surfboard 6141 modem. I tried a factory reset, but it did not make a difference. The panic occurs in a function related to neighbor advertisements (ecm_interface_send_neighbour_solicitation), so I tried disabling IPv6 a week ago - no reboot since (though this is just a workaround, of course; you'd expect a modern router to properly support IPv6). The panic log indicates that an alignment exception occurs when executing a LDREX instruction; I believe this occurs in atomic_dec_and_test in neigh_release (which is inlined in ecm_interface_send_neighbour_solicitation; this atomically decrements the reference count in the neighbour struct). I am not too familiar with ARMv7; does LDREX require a page-aligned pointer? If so, I think this is the cause - the refcnt member in struct neighbour is at offset 0x18, which isn't page-aligned. I can provide a full panic log for your engineers to look at.
Wow. First time I've seen THAT. What firmware is on the Orbi? Maybe this is a good time for a "Factory Reset" and configure from scratch. If it is less than one year old, it should be under warranty.
