[PATCH] Bus error on ARMv7 when using OSPF

[Ondrej Zajicek]

On Mon, Jun 14, 2021 at 04:25:04PM +0100, Matthew Reeve wrote:
> Hi,
> 
> when using bird 2.0.8 on openwrt 21.02 (and other versions) on a Netgear
> R7800 router, if the OSPF protocol is used, either v2 or v3, bird
> immediately crashes on startup with:
> 
> Fri Jun 11 14:41:11 2021 daemon.info bird: Started
> Fri Jun 11 14:41:11 2021 kern.err kernel: [ 3500.853248] Alignment trap: not
> handling instruction f44c0a1f at [<00035848>] Fri Jun 11 14:41:11 2021
> kern.alert kernel: [ 3500.853283] 8<--- cut here ---
> Fri Jun 11 14:41:11 2021 kern.alert kernel: [ 3500.859363] Unhandled fault:
> alignment exception (0x801) at 0x007e0624
> Fri Jun 11 14:41:11 2021 kern.alert kernel: [ 3500.862443] pgd = 0bbef4fd
> Fri Jun 11 14:41:11 2021 kern.alert kernel: [ 3500.868821] [007e0624]
> *pgd=5d6ca835, *pte=5c40b75f, *ppte=5c40bc7f
> 
> 
> This router uses an ARMv7 processor and the issue seems to be to do with
> memory alignment issues. I've debugged it and traced it to an access to the
> top_hash_entry struct. I've found that if I add the PACKED macro to the
> struct definition then it fixes the problem, as per this patch:

Hi

Thanks, could you try to get backtrace from the coredump using gdb to see
where is the invalid access?


-- 
Elen sila lumenn' omentielvo

Ondrej 'Santiago' Zajicek (email: santiago at crfreenet.org)
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"To err is human -- to blame it on a computer is even more so."