Hi!
I've been doing a full rebuild of the Debian archive, building all
source packages targeting armel and armhf using arm64 hardware. We are
planning in future to move all of our 32-bit armel/armhf builds to
using arm64 machines, so this rebuild is to identify packages that
might have problems with this configuration.
A feature of the arm64 kernel is that it does *not* support fixing up
code with broken alignment, so code that might have built and run OK
on our older armel/armhf build machines due to kernel fixups will now
fail.
When building your package, I've found a bus error (aka alignment
fault). The full log is online at
https://www.einval.com/debian/arm/rebuild-logs/armel/FAIL/nanomsg_1.1.5+dfsg-1_armel.log
for reference
I've done a quick bit of debugging to find the source of the
bug. Here's a gdb stacktrace and variable printout to demonstrate the
problem.
(sid-armel)steve@mjolnir:~/debian/build/nanomsg/nanomsg-1.1.5+dfsg$ gdb obj-arm-linux-gnueabi/ws_async_shutdown obj-arm-linux-gnueabi/core
...
warning: core file may not match specified executable file.
[New LWP 5270]
[New LWP 5271]
[New LWP 5268]
[New LWP 5277]
[New LWP 5275]
[New LWP 5278]
[New LWP 5269]
[New LWP 5272]
[New LWP 5273]
[New LWP 5276]
[New LWP 5274]
[New LWP 5279]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/arm-linux-gnueabi/libthread_db.so.1".
Core was generated by `/home/steve/debian/build/nanomsg/nanomsg-1.1.5+dfsg/obj-arm-linux-gnueabi/ws_as'.
Program terminated with signal SIGBUS, Bus error.
#0 0xf7d14b58 in nn_sws_recv (self=0x17ed380, msg=0x0) at ./src/transports/ws/sws.c:573
573 cmsg->cmsg_level = NN_WS;
[Current thread is 1 (Thread 0xf7316460 (LWP 5270))]
(gdb) p cmsg
$1 = (struct nn_cmsghdr *) 0xf7315d9d
(gdb) p *cmsg
$2 = {cmsg_len = 0, cmsg_level = 0, cmsg_type = 0}
(gdb) p cmsg->smsg_level
There is no member named smsg_level.
(gdb) p cmsg->cmsg_level
$3 = 0
(gdb) p &cmsg->cmsg_level
$4 = (int *) 0xf7315da1
The definition of nn_cmsghdr:
struct nn_cmsghdr {
size_t cmsg_len;
int cmsg_level;
int cmsg_type;
};
says that cmsg_level is an int, but the structure here is not aligned
appropriately.