Re: Question about Clang/LLVM addresssanitizer

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Re: Question about Clang/LLVM addresssanitizer

Manas via cfe-dev
<quote author='Deep Majumder via cfe-dev'>

> On Sep 20, 2016, at 9:47 PM, ZhaoKang via cfe-dev <[hidden email]>
> wrote:
> You mentioned that 'Some global settings in the system may for some reason
> reject such huge mappings.'
> And I want to know which kinds of settings may have this effect?

cat /proc/sys/vm/overcommit_memory on your system.

The default value is 0, which means allow overcommit heuristically when it
seems likely to work.

If, however, your system has that set to 2 (which I'm guessing it does),
linux will ignore the MAP_NORESERVE flag, and *always* demands you have
enough ram and swap to hold everything that might ever possibly be written.

In that case, either set it back to 0, or else add 16TB or so of swapspace
to your system.

Almost nobody ever sets that option to 2, because it's almost completely
useless to do so, and just breaks stuff. :)


Can you please let me know how did you find the problem using the strace of the sample from the 2 machines.

Thanks & Regards,
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