More on shutdown segmentation fault

[Peter Naulls]

Sorry, misplaced the original, but this is what I'm seeing as a reminder:

# reboot
# [  532.990424] br-lan: port 1(lan1) entered disabled state
[  533.003610] device lan1 left promiscuous mode
[  533.012515] device eth0 left promiscuous mode
[  533.021723] br-lan: port 1(lan1) entered disabled state
[  533.091920] mtk_soc_eth 1e100000.ethernet eth0: Link is Down
[  533.106979] mt7530 mdio-bus:1f lan1: Link is Down
[  534.634945] do_page_fault(): sending SIGSEGV to ModemManager for invalid read 
access from 00000000
[  534.652987] epc = 77c6617d in libglib-2.0.so.0.7000.4[77c2f000+df000]
[  534.665892] ra  = 555cf8bf in ModemManager[55590000+183000]
[  537.630560] reboot: Restarting system

In unrelated testing today, I realized this is probably a file handling problem.
MM is possibly trying to read/write or open a file somewhere and failing, 
because the filesystem is read-only at this point. So somewhere there might be
some additional error checking to do on a file operations.

I found an error just like this in px5g-mbedtls today too.