LinuxQuestions.org - [SOLVED] mmap: getting SIGBUS when writing to a position that is bellow what I requested

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mmap: getting SIGBUS when writing to a position that is bellow what I requested

So!

I'm working with shared memory.

I have requested mmap to get me shared memory of a given size to write onto:

Code:

char * sharedMemory = mmap(0, memorySize, PROT_WRITE, MAP_SHARED, sharedMemFd, 0xf0000);

(taken from other shared memory examples, guys). Now, memorySize is o ver 6*10^6 at the time.... but when I try to do memcpy on it I get a SIGBUS. I isolated the index where the problem is happening and it's on char index 5169152. Why is that? Is there a max value that can be mmapped or something?

Thanks in advance.

Couple of things, we may try/check:

1) Change the 1st parameter to mmap() to NULL or any valid address.
2) Cross-check the value of 'memorySize'.

The problem was the offset I was using: 0xf0000 (taken straight from the examples). I needed them to be in 0 and now it's working like a charm. Thanks for your kind help anyway.