CM4F Assertion in port.c after update to V11.0.1

Kernel
16

I’ve continued evaluating the problem in the debugger by adding some debug variables. This shows why the assertion fails.

volatile uint32_t test3257 = 5;
volatile uint32_t test3258 = 6;
volatile uint32_t test3259 = 7;

void vTaskStepTick( TickType_t xTicksToJump )
{
    TickType_t xUpdatedTickCount;

    traceENTER_vTaskStepTick( xTicksToJump );

    /* Correct the tick count value after a period during which the tick
     * was suppressed.  Note this does *not* call the tick hook function for
     * each stepped tick. */

    test3257 = xTickCount;
    test3258 = xTicksToJump;

    xUpdatedTickCount = test3257 + test3258;

// xUpdatedTickCount = xTickCount + xTicksToJump;

    test3259 = xNextTaskUnblockTime;
    configASSERT( xUpdatedTickCount <= test3259 );

// configASSERT( xUpdatedTickCount <= xNextTaskUnblockTime );
…

test3257 is set to a value of 20009FFF₁₆, which is the end of RAM and not the tick count. The other two test variables are correct. This triggers the exception.

the corresponding assembly is

4574 test3257 = xTickCount;
08005d60: ldr r3, [pc, #228] ; (0x8005e48 <prvIdleTask.lto_priv.55+636>) // load addr of variable test3257 to r3
08005d62: ldr r2, [r7, #0] //load value of xTickCount by de-referencing r7
08005d64: str r2, [r3, #0] //store

the line where r7 is set to the address of xTickCount is before entering/leaving sleep mode. Any idea if this might cause the problem?

Another strange thing is, this happens only on power-up / cold boot, not on reset. After a reset the values are correct and the system boots normally.