Hello Carl,
On Mon, Aug 31, 2026 at 12:23:35PM -0700, Carl Wuebker wrote:
> Package: linux-libc-dev
> Version: 6.12.107-1
> Severity: normal
> Dear Maintainer,
>
> The problem is that sbrk(2) checks each new request against the machine's
> total RAM + swap space. It should check each new request against total RAM
> + swap space - memory that has already been allocated to the current
> process.
>
> Steps to reproduce:
> 1. Compile & run the program below on a machine with 32 GiB memory & 24 GiB
> swap
>
> --- eatmem_bad.c
> #include <stdio.h>
> #include <unistd.h>
>
> intptr_t bigMem = (intptr_t) 128LL*1024*1024*1024;
>
> int main(int argc,char *argv[]) {
> intptr_t i;
> unsigned long long mem;
>
> if (argc != 1)
> { (void) fprintf(stderr,"Usage: %s\n", argv[0]); return 2; }
>
> mem=0;
> for (i = bigMem; i >= 16; i /= 2)
> if (sbrk(i) != (void *) -1)
> mem |= i;
>
> (void) printf("Memory=%llu MiB\n",mem / (1024*1024));
>
> return 0;
> }
> ---
>
> Expected (and correct) result:
> Memory=56718 MiB
>
> Actual result:
> Memory=65535 MiBI wonder what your actual problem is. It's quite usual that a process can get more memory assigned than there is physically available. That's called "overcommitting" if you want to research about that. Unless there is a real problem to solve I suggest to either ignore it or discuss with upstream what to do. Best regards Uwe
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