SIGBUS due to alignment exception

[Dizaam]

There are several bug reports related to unaligned memory access on armv7h for various applications.

[url]https://github.com/golang/go/issues/58548[/url]
[url]https://archlinuxarm.org/forum/viewtopic.php?f=60&t=16162&p=69907&hilit=alignment[/url]

I'm having the same problem running bird daemon on raspberry pi 3 (armv7h). The problem seems to happen along with unaligned access in neon instructions. Here is some debug output.

[code]
# gdb --args ./bird -d
Program received signal SIGBUS, Bus error.
0x004496c4 in bgp_get_prefix (path_id=0, net=<optimized out>, c=0x51ed08) at proto/bgp/attrs.c:1700
1700 *px = (struct bgp_prefix) { };
(gdb) bt
#0 0x004496c4 in bgp_get_prefix (path_id=0, net=<optimized out>, c=0x51ed08) at proto/bgp/attrs.c:1700
#1 bgp_rt_notify (old=0x53cc78, new=0x20, n=0x51e930, C=<optimized out>, P=0xf0) at proto/bgp/attrs.c:1958
#2 bgp_rt_notify (P=0xf0, C=<optimized out>, n=0x51e930, new=0x20, old=0x0) at proto/bgp/attrs.c:1928
#3 0x00435a58 in rt_notify_basic (c=0x51ed08, net=0xb6944020, new=<optimized out>, old=<optimized out>, refeed=0) at nest/rt-table.c:836
#4 0x0042b9f4 in do_feed_channel (e=<optimized out>, n=0x0, c=<optimized out>) at nest/rt-table.c:2973
#5 rt_feed_channel (c=<optimized out>) at nest/rt-table.c:3018
#6 channel_feed_loop (ptr=0x51ed08) at nest/proto.c:276
#7 channel_feed_loop (ptr=0x51ed08) at nest/proto.c:259
#8 0x0040806c in ev_run (e=0x5408d8) at lib/event.c:86
#9 ev_run_list_limited (l=<optimized out>, limit=<optimized out>) at lib/event.c:187
#10 io_loop () at sysdep/unix/io.c:2217
#11 main (argc=<optimized out>, argv=<optimized out>) at sysdep/unix/main.c:958
(gdb) x/i $pc-4
0x4496c0 <bgp_rt_notify+2056>: vst1.8 {d16-d17}, [r4 :64]
(gdb) p/x $r4
$2 = 0xb694101c
(gdb) p/x $sp
$3 = 0xbefff930
[/code]

The following modification in PKGBUILD of GCC might cause the problem.

[url]https://github.com/archlinuxarm/PKGBUILDs/commit/8683b7745b3e1ad9cf4ea56220efaa9fd09b8fbf[/url]

When GCC by default uses neon.