Bus Error reading RFactor2 telemetry

[BenjaminRengle]

Hi,
First i want to thank you for that awesome project.

I tried to get simd working with LMU and it looks like simd is starting to read the RFactor2 telemetry. However shortly after simd crashes with a Bus error:

`./simd --nodaemon --nomemmap -vv
starting simd
2026-07-31T05:48:49Z - simd INFO: Initializing logs
2026-07-31T05:48:49Z - simd INFO: Started. Found home directory and interpreted parameters.

2026-07-31T05:48:49Z - simd INFO: Opened and validated simd configuration file
2026-07-31T05:48:49Z - simd INFO: Successfullly loaded configuration file
2026-07-31T05:48:49Z - simd INFO: Opening universal shared memory
2026-07-31T05:48:49Z - simd INFO: Successfully opened universal shared memory (fd: 3)
2026-07-31T05:48:49Z - simd INFO: SimApi Version: 1

2026-07-31T05:48:49Z - simd DEBUG: setting initial app state
2026-07-31T05:48:49Z - simd INFO: Searching for sim data... Press q to quit...

2026-07-31T05:48:49Z - simd INFO: Starting Bridge Polling Thread.
2026-07-31T05:49:07Z - simd INFO: Detected simulator id 2399420, starting appropriate bridge if necessary.
2026-07-31T05:49:07Z - simd DEBUG: sim 2399420 does not require a compatibility exe, will continue to mapping data
sh: line 1: notify-send: command not found
2026-07-31T05:49:07Z - simd DEBUG: datacheckcallback triggered
2026-07-31T05:49:07Z - simd DEBUG: RFactor2 telemetry file found
Bus error (core dumped) ./simd --nodaemon --nomemmap -vv
`

Journalctl shows me the following:

`Jul 31 07:49:07 bazziteSimRig systemd-coredump[17818]: Process 17318 (simd) of user 1000 terminated abnormally with signal 7/BUS, processing...
Jul 31 07:49:07 bazziteSimRig audit: BPF prog-id=128 op=LOAD
Jul 31 07:49:07 bazziteSimRig audit: BPF prog-id=129 op=LOAD
Jul 31 07:49:07 bazziteSimRig audit: BPF prog-id=130 op=LOAD
Jul 31 07:49:07 bazziteSimRig systemd[1]: Started systemd-coredump@3-12289-17818_34121-0.service - Process Core Dump (PID 17818/UID 0).
Jul 31 07:49:07 bazziteSimRig audit[1]: SERVICE_START pid=1 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:init_t:s0 msg='unit=systemd-coredump@3-12289-17818_34121-0 comm="systemd" exe="/usr/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'
Jul 31 07:49:07 bazziteSimRig systemd-coredump[17819]: [🡕] Process 17318 (simd) of user 1000 dumped core.

                                                   Stack trace of thread 17318:
                                                   #0  0x00007f0a970862e7 map_rfactor2_data (libsimapi.so.1 + 0xd2e7)
                                                   #1  0x00007f0a97081564 simapi_datamap (libsimapi.so.1 + 0x8564)
                                                   #2  0x00007f0a970809ca simapi_get_sim (libsimapi.so.1 + 0x79ca)
                                                   #3  0x000055a67e996f7e datacheckcallback (simd + 0x4f7e)
                                                   #4  0x00007f0a970bf3af n/a (/usr/lib/libuv.so.1.0.0 + 0xd3af)
                                                   #5  0x00007f0a970c7d32 n/a (/usr/lib/libuv.so.1.0.0 + 0x15d32)
                                                   #6  0x000055a67e997c3e main (simd + 0x5c3e)
                                                   #7  0x00007f0a96e54781 n/a (/usr/lib/libc.so.6 + 0x27781)
                                                   #8  0x00007f0a96e548b9 n/a (/usr/lib/libc.so.6 + 0x278b9)
                                                   #9  0x000055a67e995705 _start (simd + 0x3705)
                                                   ELF object binary architecture: AMD x86-64

Jul 31 07:49:07 bazziteSimRig systemd[1]: systemd-coredump@3-12289-17818_34121-0.service: Deactivated successfully.
`

The rF2SharedMemoryMapPlugin_Wine.dll is present in the LMU plugins folder and the plugin is activated.
Otherwise i'd assume simd would not show me the log "RFactor2 telemetry file found" anyways i assume.

A simd log file under /tmp is created but its empty.

Any help how to debug this or find the issue is highly appreciated.

Best regards

[Spacefreak18]

if you're not afraid, you could put printf statements inside map_rfactor2_data

but i imagine if it makes it that far, like you said, the shared memory file must exist, and it bombs immediately when it tries making sense of the data inside of the file.

are both files non zero and have readable permissions to your user?

hexdump /dev/shm/$rFactor2SMMP_Telemetry$
hexdump /dev/shm/$rFactor2SMMP_Scoring$

from talking to other bazzite users usually it is something like this where the container or whatever simd is running under can't see the shared memory file.

if that's the case though it's still a bug on my end because I should check for that before I assume the file is good and start reading it.

[BenjaminRengle]

Thanks for your swift reply.
I checked the rFactor2SMMP files in /dev/shm/ and it looks like all of the files are empty:
-rw-r--r-- 1 bazzite bazzite 0 Jul 31 16:29 '$rFactor2SMMP_Extended$'
-rw-r--r-- 1 bazzite bazzite 0 Jul 31 16:29 '$rFactor2SMMP_ForceFeedback$'
-rw-r--r-- 1 bazzite bazzite 0 Jul 31 16:29 '$rFactor2SMMP_Graphics$'
-rw-r--r-- 1 bazzite bazzite 0 Jul 31 16:29 '$rFactor2SMMP_HWControl$'
-rw-r--r-- 1 bazzite bazzite 0 Jul 31 16:29 '$rFactor2SMMP_MultiRules$'
-rw-r--r-- 1 bazzite bazzite 0 Jul 31 16:29 '$rFactor2SMMP_PitInfo$'
-rw-r--r-- 1 bazzite bazzite 0 Jul 31 16:29 '$rFactor2SMMP_PluginControl$'
-rw-r--r-- 1 bazzite bazzite 0 Jul 31 16:29 '$rFactor2SMMP_Rules$'
-rw-r--r-- 1 bazzite bazzite 0 Jul 31 16:29 '$rFactor2SMMP_RulesControl$'
-rw-r--r-- 1 bazzite bazzite 0 Jul 31 16:29 '$rFactor2SMMP_Scoring$'
-rw-r--r-- 1 bazzite bazzite 0 Jul 31 16:29 '$rFactor2SMMP_Telemetry$'
-rw-r--r-- 1 bazzite bazzite 0 Jul 31 16:29 '$rFactor2SMMP_Weather$'
-rw-r--r-- 1 bazzite bazzite 0 Jul 31 16:29 '$rFactor2SMMP_WeatherControl$'

stat rFactor2SMMP_Telemetry reports a size of 0
hexdump for all of those files does report nothing.

It makes sense now that simd crashes out reading those files.
I'd assume the issue lies in the wine rF2SharedMemoryMapPlugin?

[BenjaminRengle]

Sorry I think i found the issue.
I still had the non wine "rFactor2SharedMemoryMapPlugin64.dll" present and activated in the plugins folder. Once i removed it and just left the Wine dll enabled the files are non Zero anymore and are perfectly parsed by simd:

./simd --nodaemon --nomemmap -vv
starting simd
2026-07-31T14:49:42Z - simd INFO: Initializing logs
2026-07-31T14:49:42Z - simd INFO: Started. Found home directory and interpreted parameters.

2026-07-31T14:49:42Z - simd INFO: Opened and validated simd configuration file
2026-07-31T14:49:42Z - simd INFO: Successfullly loaded configuration file
2026-07-31T14:49:42Z - simd INFO: Opening universal shared memory
2026-07-31T14:49:42Z - simd INFO: Successfully opened universal shared memory (fd: 3)
2026-07-31T14:49:42Z - simd INFO: SimApi Version: 1

2026-07-31T14:49:42Z - simd DEBUG: setting initial app state
2026-07-31T14:49:42Z - simd INFO: Searching for sim data... Press q to quit...

2026-07-31T14:49:42Z - simd INFO: Starting Bridge Polling Thread.
2026-07-31T14:49:57Z - simd INFO: Detected simulator id 2399420, starting appropriate bridge if necessary.
2026-07-31T14:49:57Z - simd DEBUG: sim 2399420 does not require a compatibility exe, will continue to mapping data
sh: line 1: notify-send: command not found
2026-07-31T14:49:57Z - simd DEBUG: datacheckcallback triggered
2026-07-31T14:49:57Z - simd DEBUG: RFactor2 telemetry file found

Sorry again for that.
Ticket can be closed i guess

[Spacefreak18]

i'm so glad you got it working, i'll keep the ticket open for a bit, so this week i'll fix it so that it doesn't crash if the files are zero sized