we were using the 4.4.277-cip60-rt35 kernel and it happens from
time to time that the kernel watchdog is triggered and our
embedded devices gets resetted.
This message specially appers when we run the CodeSYS Runtime (PLC
[ 536.133081] NMI watchdog:
BUG: soft lockup - CPU#0 stuck for 23s! [BlkDrvUdp:330]
[ 536.140637] Modules linked
[ 536.143756] CPU: 0 PID:
330 Comm: BlkDrvUdp Not tainted
[ 536.152489] Hardware name:
Freescale Vybrid VF5xx/VF6xx (Device Tree)
[ 536.158967] task: 86bd7700
ti: 841aa000 task.ti: 841aa000
[ 536.164408] PC is at
[ 536.168450] LR is at
[ 536.172487] pc :
[<80069a40>] lr : [<80069a10>] psr: a0070013
[ 536.172487] sp : 841abe90
ip : 86896244 fp : 841abf4c
I contacted the support and they told me following about usage of
mutexes of the runtime:
The runtime is using pi mutexes
and also with recursive attribute.
and that they got other customers that had also problems with this
My current knowledge of the linux kernel is not big enough to
solve that problem by myself. But i'm willed to learn more about
the kernel and maybe solve the problem by own.
Can anyone give me a hint how to continue investigation of that
Maybe someone has solved that problem for another target hardware?
Every RTFM hint is also welcome, when it least tell me the manual
to dig trough :)
I tried the latest 4.19.206-cip57-rt22-kernel. In this kernel
version the problem reported above doesn't occur.
For now we will use the 4.19 kernel.