[LTP] [PATCH 3/3] syscalls: munmap03: Convert to new API
Ricardo B. Marlière
rbm@suse.com
Fri Jul 4 18:35:15 CEST 2025
On Fri Jul 4, 2025 at 1:26 PM -03, Andrea Cervesato wrote:
> On 7/4/25 5:23 PM, Ricardo B. Marlière wrote:
>> Most of those are for mmap. The only one left seems to be ENOMEM, which
>> I don't think it's viable to test. WDYT?
> I guess you mean:
>
> ENOMEM The process's maximum number of mappings would have been
> exceeded. This error can also occur for munmap(), when
> unmapping a region in the middle of an existing mapping,
> since this results in two smaller mappings on either side
>
> of the region being unmapped.
>
> Luckily it is testable, but we need a new test for that. What we can do
> is to read
> https://docs.kernel.org/admin-guide/sysctl/vm.html#max-map-count and to
> map the maximum amount of memory map areas. Then we munmap() in the
> middle of one of them, resulting in +1 mapped areas and obtaining ENOMEM
> from the syscall. Feel free to explore it.
>
Thanks for the pointers, I'll give it a shot 8-)
> - Andrea
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