# dmesg shows "... used greatest stack depth: xxx bytes left"

## boerns

Hi,

what does these messages in dmesg mean:

[  305.362895] kworker/dying (676) used greatest stack depth: 11896 bytes left

[ 1364.146634] patch (9914) used greatest stack depth: 11592 bytes left

[ 4868.461541] cc1 (5221) used greatest stack depth: 10920 bytes left

[13339.375000] cc1plus (1346) used greatest stack depth: 10504 bytes left

[13502.827982] kworker/dying (16153) used greatest stack depth: 9944 bytes left

In backgroud emerge -e system is running and  memtester.

Greetings

Alex

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## NeddySeagoon

boerns,

They are informational messages about what is happening on the kernel stack.

The stack is a dynamic memory structure of a fixed maximun size.

Running out of kernel stack space is a very bad thing.

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## boerns

What do you mean with "Very bad thing"?

Does it mean to less memory?

Wrong kernel-config?

CPU or Memory defect?

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## NeddySeagoon

boerns,

Haveing too big a stack is wasteful.  You have 9944 bytes left, which is a safe margin.

If you run out of stack space and the kernel realises, it will panic, as it cannot continue.

If you overflow the stack, some other data structure may be will be overwritten. Effects depend on what gets overwritten.

Either outcome is bad.

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