Re: mmap 0-th page

[Jiri Slaby <jirislaby@kernel.org>]

On 31. 07. 24, 9:39, Jiri Slaby wrote:
> On 26. 07. 24, 12:36, michal.hrachovec@volny.cz wrote:
>> I am trying to allocate the 0-th page with mmap function in my code.
>> I am always getting this error with this error-code: mmap error ffffffff
>> Then I was searching the internet for this topic and I have found the 
>> same topic at stackoverflow web pages.
> 
> 
>          char *zero = mmap(NULL, 4096, PROT_READ | PROT_WRITE, 
> MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, -1, 0);
>          *(char *)(NULL) = 'A';
>          printf("%c\n", *zero);
> 
> still yields 'A' here with 6.10.2 w/ vm.mmap_min_addr=0.
Yeah and mind LSMs...

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js
suse labs