[BUG] SIGBUS issue on arm64 with 32-bit userland -> Unhandled fault: alignment fault (0x92000021)

[dtech]

The original topic name was: "Bus error" error with an ASUS BW-16D1HT (3.10-MK) drive in a Raidsonic IB-525-U3 (JMS567) case
However, since then it has been proven that the error does not affect the drive and the external USB case, so I renamed it.

First of all, the above drive+case combo works perfectly under Windows 10.
But I tried under OSMC (Vero 4K+) and LibreELEC-AML (multiple S905D, S912), on several Amlogic devices (armhf), but with the above combination I get this error:

Code: Select all

osmc@Vero4K-Plus:~$ makemkvcon --debug info disc:0
MakeMKV v1.17.6 linux(armhf-release) started
Debug logging enabled, log will be saved as file:///home/osmc/MakeMKV_log.txt
Profile parsing error: default profile missing, using builtin default
Bus error

Unfortunately, the log does not contain any useful information about the error:

Code: Select all

Debug log started at Tue Jan 23 12:23:45 2024 , written by MakeMKV v1.17.6 linux(armhf-release)
001005:0000 MakeMKV v1.17.6 linux(armhf-release) started
001004:0000 Debug logging enabled, log will be saved as file:///home/osmc/MakeMKV_log.txt
Using 262272KB for read cache.
001009:0000 Profile parsing error: default profile missing, using builtin default
Network access is ENABLED, CURL version 7.74.0/OpenSSL/1.1.1w/1.43.0 (arm-unknown-linux-gnueabihf) , proxy server not set.

I had no problems with any of the tested configurations with two other non-UHD drives (Samsung SE-506BB slim USB drive and LG BE06LU10 standard USB drive), even though they are USB 2.0.

However, I don't know if the drive (ASUS BW-16D1HT) or the external case (Raidsonic IB-525-U3) can be the culprit in the "Bus error". Does anyone have any ideas?

[dtech]

I think I got a bit closer to the problem, because the error only exists on systems that use a 64-bit (aarch64) kernel but have a 32-bit (armhf) userspace.

At the moment, I haven't been able to try it on native 64-bit. However, it was tested on native 32-bit with Amlogic S812 SoC, makemkvc does not give errors, but there is no hardware acceleration for H.265 for 10-bit HDR. (But it started with software playback, although it is quite a slideshow, but of course this is not the fault of makemkv.)

So the problem happens when try to call the 64-bit sg module with the armhf binary, but I have no idea how to debug this.

[dtech]

Today I was able to test it and it works properly with 64-bit kernel and 64-bit userspace as well.

Unfortunately, I have no idea how to make it work on an aarch64 kernel and a 32-bit (armhf) userspace. In most cases, this combination is still in use as a general standard.

The situation is the same on Raspberry Pi 4, not only on Amlogic boxes.

[dtech]

A small update, because I didn't look at the kernel log before, but there is an entry there:

Code: Select all

Jan 31 07:45:18 X92 kernel: Unhandled fault: alignment fault (0x92000021) at 0x00000000e3608ad1

Okay, try to run gdb...

Code: Select all

X92:~ # gdb --args makemkvcon info disc:0
GNU gdb (GDB) 8.2.1
Copyright (C) 2018 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
Type "show copying" and "show warranty" for details.
This GDB was configured as "armv8a-libreelec-linux-gnueabi".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
    <http://www.gnu.org/software/gdb/documentation/>.

For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from makemkvcon...(no debugging symbols found)...done.
(gdb) run
Starting program: /storage/.kodi/addons/service.makemkv/bin/makemkvcon info disc:0
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/usr/lib/libthread_db.so.1".
[New Thread 0xf5f2b440 (LWP 3140)]
MakeMKV v1.17.7 linux(armhf-release) started
Profile parsing error: default profile missing, using builtin default
[New Thread 0xe43d9440 (LWP 3141)]
[New Thread 0xe39ff440 (LWP 3142)]
The new version 1.17.8 is available for download at http://www.makemkv.com/download/

Thread 3 "makemkvcon" received signal SIGBUS, Bus error.
[Switching to Thread 0xe43d9440 (LWP 3141)]
0xab090e5c in ?? ()
(gdb)

Unfortunately, this is not informative for me, so I don't know if it's a kernel or makemkvcon issue, or perhaps one of the affected dependent libraries.

This error only occurs with mixed 64-bit kernel (aarch64) + 32-bit userspace (armhf). Everything works under native 32+32-bit and 64+64-bit ARM systems, but in many cases only the hybrid system is possible (OSMC also uses this for Vero 4+ and V), so it would be nice to solve this problem.

[dtech]

I would appreciate it if a MakeMKV developer would check this bug, because it is likely a bug in the closed source part of the program. Thanks.

[dcoke22]

I would appreciate it if a MakeMKV developer would check this bug, because it is likely a bug in the closed source part of the program. Thanks.

I don't see MakeMKV's developer on the forum very much. You might have better luck if you email him at support@makemkv.com.

[dtech]

I don't see MakeMKV's developer on the forum very much. You might have better luck if you email him at support@makemkv.com.

Thanks, I wrote an email, I hope someone responds, because it would be great if this problem could be solved.