Diagnosing further, I've found that this happens when accessing a certain file:
dannf@mustang:~$ ls -l /usr/bin/qemu-system-aarch64 -rwxr-xr-x 1 root root 4998496 Mar 12 21:17 /usr/bin/qemu-system-aarch64 dannf@mustang:~$ ls -l /usr/lib/python2.7/six.pyc [ 3586.472110] Unable to handle kernel paging request at virtual address 3ffffffffffffc [ 3586.479819] pgd = ffffffc0fdebf000 [ 3586.483237] [3ffffffffffffc] *pgd=00000040fde7d003, *pud=00000040fde7d003, *pmd=0000000000000000 [ 3586.492027] Internal error: Oops: 96000004 [#13] SMP [ 3586.496965] Modules linked in: xt_conntrack ipt_REJECT nf_reject_ipv4 ebtable_filter ebtables ip6t [ 3586.539676] CPU: 5 PID: 1932 Comm: ls Tainted: G D 3.19.0-12-generic #12-Ubuntu [ 3586.547982] Hardware name: APM X-Gene Mustang board (DT) [ 3586.553266] task: ffffffc3e8a38c40 ti: ffffffc0fc68c000 task.ti: ffffffc0fc68c000 [ 3586.560712] PC is at __d_lookup_rcu+0x80/0x17c [ 3586.565133] LR is at lookup_fast+0x4c/0x2f0 [ 3586.569293] pc : [<ffffffc000229eec>] lr : [<ffffffc00021ce68>] pstate: 00000145 [ 3586.576648] sp : ffffffc0fc68fb40 [ 3586.579942] x29: ffffffc0fc68fb40 x28: ffffffc0fc68c000 [ 3586.585245] x27: ffffffffffffffff x26: 0000000000000007 [ 3586.590546] x25: ffffffc3ed26a033 x24: ffffffc0fc68fd20 [ 3586.595848] x23: 0000000725cabf8e x22: ffffffc0fc68fbfc [ 3586.601150] x21: ffffffc3ed53b780 x20: 003ffffffffffff8 [ 3586.606451] x19: 0040000000000000 x18: 0000000000000000 [ 3586.611754] x17: 00000000004292d0 x16: ffffffc000215d3c [ 3586.617057] x15: ffffffffffffffff x14: 0000007faf35c16c [ 3586.622360] x13: ffffffffffffffff x12: 0000000000000010 [ 3586.627662] x11: 0000000000000000 x10: fefefefefefefeff [ 3586.632965] x9 : 0000007fca1ade6c x8 : 535f474458006379 [ 3586.638268] x7 : 0000000000000000 x6 : 0000000000000020 [ 3586.643571] x5 : 0000000000000000 x4 : ffffffc000b64f60 [ 3586.648872] x3 : 0000000000000015 x2 : ffffffc3eec00000 [ 3586.654174] x1 : 000000000000000b x0 : 00000000001ed681 [ 3586.659475] [ 3586.660956] Process ls (pid: 1932, stack limit = 0xffffffc0fc68c058) [ 3586.667275] Stack: (0xffffffc0fc68fb40 to 0xffffffc0fc690000) [ 3586.672991] fb40: fc68fba0 ffffffc0 0021ce68 ffffffc0 fc68fd10 ffffffc0 00000000 00000000 [ 3586.681126] fb60: fc68fc70 ffffffc0 fc68fc60 ffffffc0 dfa06020 ffffffc3 ed53b780 ffffffc3 [ 3586.689260] fb80: 0000011a 00000000 0000004f 00000000 00b6e000 ffffffc0 c3e4c240 ffffffbe [ 3586.697395] fba0: fc68fc00 ffffffc0 0021f578 ffffffc0 fc68fd10 ffffffc0 00000000 00000000 [ 3586.705529] fbc0: 00000040 00000000 ed26a020 ffffffc3 ffffff9c 00000000 00000015 00000000 [ 3586.713663] fbe0: 0000011a 00000000 ed26a020 ffffffc3 ffffff9c 00000000 000994ec ffffffc0 [ 3586.721798] fc00: fc68fc90 ffffffc0 0021fbe4 ffffffc0 ed26a000 ffffffc3 fc68fd10 ffffffc0 [ 3586.729932] fc20: ed26a000 ffffffc3 00000000 00000000 ffffff9c 00000000 00000015 00000000 [ 3586.738066] fc40: 0000011a 00000000 0000004f 00000000 00b6e000 ffffffc0 ca1ade4c 0000007f [ 3586.746201] fc60: 00000000 00000000 00000000 00000000 fc68fe20 ffffffc0 00000015 00000000 [ 3586.754335] fc80: fc68fcd0 ffffffc0 0022133c ffffffc0 fc68fcd0 ffffffc0 00221360 ffffffc0 [ 3586.762469] fca0: ed26a000 ffffffc3 00000000 00000000 00000000 00000000 ffffff9c 00000000 [ 3586.770604] fcc0: fc68fe20 ffffffc0 00b6fc10 ffffffc0 fc68fdb0 ffffffc0 002213f0 ffffffc0 [ 3586.778738] fce0: ffffff9c 00000000 ca1ade4c 0000007f 00000000 00000000 fc68fe20 ffffffc0 [ 3586.786872] fd00: fc68fe68 ffffffc0 00129750 ffffffc0 dfa06020 ffffffc3 ed53b780 ffffffc3 [ 3586.795007] fd20: 25cabf8e 00000007 ed26a033 ffffffc3 dfa06020 ffffffc3 ed5da180 ffffffc3 [ 3586.803141] fd40: ff659c88 ffffffc0 00000040 00000002 00000536 00000000 00000000 00000000 [ 3586.811275] fd60: 00000000 00000000 0012a07c ffffffc0 00000001 00000000 00000000 00000000 [ 3586.819410] fd80: 00000081 00000000 af49e770 0000007f 7fffffff 00000000 00000003 00000000 [ 3586.827544] fda0: 00000000 00000000 00000062 00000000 fc68fde0 ffffffc0 002157b0 ffffffc0 [ 3586.835678] fdc0: 00000000 00000000 00000000 00000000 ffffff9c 00000000 ca1ade4c 0000007f [ 3586.843813] fde0: fc68fe30 ffffffc0 00215d78 ffffffc0 ffffff9c ffffffff ca1ade4c 0000007f [ 3586.851947] fe00: 00000100 00000000 22811c90 00000000 80000000 00000000 001d468c ffffffff [ 3586.860081] fe20: ca1ad0a0 0000007f 0008609c ffffffc0 ca1ace20 0000007f 000863f0 ffffffc0 [ 3586.868216] fe40: 00000000 00000000 22811c90 00000000 ffffffff ffffffff af41614c 0000007f [ 3586.876350] fe60: ca1ace00 0000007f 000863f0 ffffffc0 00000000 00000000 af37c140 0000007f [ 3586.884484] fe80: ffffffff ffffffff af2aa05c 0000007f 20000000 00000000 00000015 00000000 [ 3586.892619] fea0: 0000011a 00000000 00000062 00000000 ca1acc90 0000007f 000863f0 ffffffc0 [ 3586.900753] fec0: 00000000 00000000 00000015 00000000 ffffff9c ffffffff ca1ade4c 0000007f [ 3586.908887] fee0: 22811c90 00000000 00000100 00000000 00000000 00000000 00000000 00000000 [ 3586.917022] ff00: ca1ad09c 0000007f 656f7277 3a2f2f1f 0000004f 00000000 22811c70 00000000 [ 3586.925156] ff20: 01010101 01010101 00000009 00000000 00000010 00000000 ffffffff ffffffff [ 3586.933290] ff40: af35c16c 0000007f ffffffff ffffffff af416138 0000007f 004292d0 00000000 [ 3586.941425] ff60: 00000000 00000000 22811c80 00000000 22811c90 00000000 00000000 00000000 [ 3586.949559] ff80: 00429000 00000000 00429000 00000000 ca1ade4c 0000007f 00000001 00000000 [ 3586.957693] ffa0: ca1ade4c 0000007f 00000002 00000000 00000000 00000000 ca1ace20 0000007f [ 3586.965828] ffc0: 00409264 00000000 ca1ace20 0000007f af41614c 0000007f 80000000 00000000 [ 3586.973962] ffe0: ffffff9c ffffffff 0000004f 00000000 00000000 00000000 00000000 00000000 [ 3586.982095] Call trace: [ 3586.984528] [<ffffffc000229eec>] __d_lookup_rcu+0x80/0x17c [ 3586.989984] [<ffffffc00021ce64>] lookup_fast+0x48/0x2f0 [ 3586.995180] [<ffffffc00021f574>] path_lookupat+0xdc/0x70c [ 3587.000550] [<ffffffc00021fbe0>] filename_lookup+0x3c/0xec [ 3587.006006] [<ffffffc00022135c>] user_path_at_empty+0x60/0xb4 [ 3587.011722] [<ffffffc0002213ec>] user_path_at+0x3c/0x50 [ 3587.016920] [<ffffffc0002157ac>] vfs_fstatat+0x64/0xbc [ 3587.022029] [<ffffffc000215d74>] SyS_newfstatat+0x38/0x60 [ 3587.027400] Code: 54000160 d360fefa 9280001b d1002274 (b85fc262) [ 3587.033478] ---[ end trace 8500912aad83ddd4 ]--- Segmentation fault dannf@mustang:~$
Diagnosing further, I've found that this happens when accessing a certain file:
dannf@mustang:~$ ls -l /usr/bin/ qemu-system- aarch64 qemu-system- aarch64 python2. 7/six.pyc e7d003, *pud=00000040fd e7d003, *pmd=0000000000 000000 rcu+0x80/ 0x17c fast+0x4c/ 0x2f0 eec>] lr : [<ffffffc00021c e68>] pstate: 00000145 eec>] __d_lookup_ rcu+0x80/ 0x17c e64>] lookup_ fast+0x48/ 0x2f0 574>] path_lookupat+ 0xdc/0x70c be0>] filename_ lookup+ 0x3c/0xec 35c>] user_path_ at_empty+ 0x60/0xb4 3ec>] user_path_ at+0x3c/ 0x50 7ac>] vfs_fstatat+ 0x64/0xbc d74>] SyS_newfstatat+ 0x38/0x60
-rwxr-xr-x 1 root root 4998496 Mar 12 21:17 /usr/bin/
dannf@mustang:~$ ls -l /usr/lib/
[ 3586.472110] Unable to handle kernel paging request at virtual address 3ffffffffffffc
[ 3586.479819] pgd = ffffffc0fdebf000
[ 3586.483237] [3ffffffffffffc] *pgd=00000040fd
[ 3586.492027] Internal error: Oops: 96000004 [#13] SMP
[ 3586.496965] Modules linked in: xt_conntrack ipt_REJECT nf_reject_ipv4 ebtable_filter ebtables ip6t
[ 3586.539676] CPU: 5 PID: 1932 Comm: ls Tainted: G D 3.19.0-12-generic #12-Ubuntu
[ 3586.547982] Hardware name: APM X-Gene Mustang board (DT)
[ 3586.553266] task: ffffffc3e8a38c40 ti: ffffffc0fc68c000 task.ti: ffffffc0fc68c000
[ 3586.560712] PC is at __d_lookup_
[ 3586.565133] LR is at lookup_
[ 3586.569293] pc : [<ffffffc000229
[ 3586.576648] sp : ffffffc0fc68fb40
[ 3586.579942] x29: ffffffc0fc68fb40 x28: ffffffc0fc68c000
[ 3586.585245] x27: ffffffffffffffff x26: 0000000000000007
[ 3586.590546] x25: ffffffc3ed26a033 x24: ffffffc0fc68fd20
[ 3586.595848] x23: 0000000725cabf8e x22: ffffffc0fc68fbfc
[ 3586.601150] x21: ffffffc3ed53b780 x20: 003ffffffffffff8
[ 3586.606451] x19: 0040000000000000 x18: 0000000000000000
[ 3586.611754] x17: 00000000004292d0 x16: ffffffc000215d3c
[ 3586.617057] x15: ffffffffffffffff x14: 0000007faf35c16c
[ 3586.622360] x13: ffffffffffffffff x12: 0000000000000010
[ 3586.627662] x11: 0000000000000000 x10: fefefefefefefeff
[ 3586.632965] x9 : 0000007fca1ade6c x8 : 535f474458006379
[ 3586.638268] x7 : 0000000000000000 x6 : 0000000000000020
[ 3586.643571] x5 : 0000000000000000 x4 : ffffffc000b64f60
[ 3586.648872] x3 : 0000000000000015 x2 : ffffffc3eec00000
[ 3586.654174] x1 : 000000000000000b x0 : 00000000001ed681
[ 3586.659475]
[ 3586.660956] Process ls (pid: 1932, stack limit = 0xffffffc0fc68c058)
[ 3586.667275] Stack: (0xffffffc0fc68fb40 to 0xffffffc0fc690000)
[ 3586.672991] fb40: fc68fba0 ffffffc0 0021ce68 ffffffc0 fc68fd10 ffffffc0 00000000 00000000
[ 3586.681126] fb60: fc68fc70 ffffffc0 fc68fc60 ffffffc0 dfa06020 ffffffc3 ed53b780 ffffffc3
[ 3586.689260] fb80: 0000011a 00000000 0000004f 00000000 00b6e000 ffffffc0 c3e4c240 ffffffbe
[ 3586.697395] fba0: fc68fc00 ffffffc0 0021f578 ffffffc0 fc68fd10 ffffffc0 00000000 00000000
[ 3586.705529] fbc0: 00000040 00000000 ed26a020 ffffffc3 ffffff9c 00000000 00000015 00000000
[ 3586.713663] fbe0: 0000011a 00000000 ed26a020 ffffffc3 ffffff9c 00000000 000994ec ffffffc0
[ 3586.721798] fc00: fc68fc90 ffffffc0 0021fbe4 ffffffc0 ed26a000 ffffffc3 fc68fd10 ffffffc0
[ 3586.729932] fc20: ed26a000 ffffffc3 00000000 00000000 ffffff9c 00000000 00000015 00000000
[ 3586.738066] fc40: 0000011a 00000000 0000004f 00000000 00b6e000 ffffffc0 ca1ade4c 0000007f
[ 3586.746201] fc60: 00000000 00000000 00000000 00000000 fc68fe20 ffffffc0 00000015 00000000
[ 3586.754335] fc80: fc68fcd0 ffffffc0 0022133c ffffffc0 fc68fcd0 ffffffc0 00221360 ffffffc0
[ 3586.762469] fca0: ed26a000 ffffffc3 00000000 00000000 00000000 00000000 ffffff9c 00000000
[ 3586.770604] fcc0: fc68fe20 ffffffc0 00b6fc10 ffffffc0 fc68fdb0 ffffffc0 002213f0 ffffffc0
[ 3586.778738] fce0: ffffff9c 00000000 ca1ade4c 0000007f 00000000 00000000 fc68fe20 ffffffc0
[ 3586.786872] fd00: fc68fe68 ffffffc0 00129750 ffffffc0 dfa06020 ffffffc3 ed53b780 ffffffc3
[ 3586.795007] fd20: 25cabf8e 00000007 ed26a033 ffffffc3 dfa06020 ffffffc3 ed5da180 ffffffc3
[ 3586.803141] fd40: ff659c88 ffffffc0 00000040 00000002 00000536 00000000 00000000 00000000
[ 3586.811275] fd60: 00000000 00000000 0012a07c ffffffc0 00000001 00000000 00000000 00000000
[ 3586.819410] fd80: 00000081 00000000 af49e770 0000007f 7fffffff 00000000 00000003 00000000
[ 3586.827544] fda0: 00000000 00000000 00000062 00000000 fc68fde0 ffffffc0 002157b0 ffffffc0
[ 3586.835678] fdc0: 00000000 00000000 00000000 00000000 ffffff9c 00000000 ca1ade4c 0000007f
[ 3586.843813] fde0: fc68fe30 ffffffc0 00215d78 ffffffc0 ffffff9c ffffffff ca1ade4c 0000007f
[ 3586.851947] fe00: 00000100 00000000 22811c90 00000000 80000000 00000000 001d468c ffffffff
[ 3586.860081] fe20: ca1ad0a0 0000007f 0008609c ffffffc0 ca1ace20 0000007f 000863f0 ffffffc0
[ 3586.868216] fe40: 00000000 00000000 22811c90 00000000 ffffffff ffffffff af41614c 0000007f
[ 3586.876350] fe60: ca1ace00 0000007f 000863f0 ffffffc0 00000000 00000000 af37c140 0000007f
[ 3586.884484] fe80: ffffffff ffffffff af2aa05c 0000007f 20000000 00000000 00000015 00000000
[ 3586.892619] fea0: 0000011a 00000000 00000062 00000000 ca1acc90 0000007f 000863f0 ffffffc0
[ 3586.900753] fec0: 00000000 00000000 00000015 00000000 ffffff9c ffffffff ca1ade4c 0000007f
[ 3586.908887] fee0: 22811c90 00000000 00000100 00000000 00000000 00000000 00000000 00000000
[ 3586.917022] ff00: ca1ad09c 0000007f 656f7277 3a2f2f1f 0000004f 00000000 22811c70 00000000
[ 3586.925156] ff20: 01010101 01010101 00000009 00000000 00000010 00000000 ffffffff ffffffff
[ 3586.933290] ff40: af35c16c 0000007f ffffffff ffffffff af416138 0000007f 004292d0 00000000
[ 3586.941425] ff60: 00000000 00000000 22811c80 00000000 22811c90 00000000 00000000 00000000
[ 3586.949559] ff80: 00429000 00000000 00429000 00000000 ca1ade4c 0000007f 00000001 00000000
[ 3586.957693] ffa0: ca1ade4c 0000007f 00000002 00000000 00000000 00000000 ca1ace20 0000007f
[ 3586.965828] ffc0: 00409264 00000000 ca1ace20 0000007f af41614c 0000007f 80000000 00000000
[ 3586.973962] ffe0: ffffff9c ffffffff 0000004f 00000000 00000000 00000000 00000000 00000000
[ 3586.982095] Call trace:
[ 3586.984528] [<ffffffc000229
[ 3586.989984] [<ffffffc00021c
[ 3586.995180] [<ffffffc00021f
[ 3587.000550] [<ffffffc00021f
[ 3587.006006] [<ffffffc000221
[ 3587.011722] [<ffffffc000221
[ 3587.016920] [<ffffffc000215
[ 3587.022029] [<ffffffc000215
[ 3587.027400] Code: 54000160 d360fefa 9280001b d1002274 (b85fc262)
[ 3587.033478] ---[ end trace 8500912aad83ddd4 ]---
Segmentation fault
dannf@mustang:~$