[mips folks Cc'd] On Thu, Oct 18, 2018 at 11:26:02AM +0800, Hongzhi, Song wrote: > Hi all, > > Ltp has a POSIX teatcase about mmap, 24-2.c. > > https://github.com/linux-test-project/ltp/blob/e816127e5d8efbff5ae53e9c2292fae22f36838b/testcases/open_posix_testsuite/conformance/interfaces/mmap/24-2.c#L94 [basically, MAP_FIXED mmap with addr + len > TASK_SIZE fails with -EINVAL on mips and -ENOMEM elsewhere] > Under POSIX standard, the expected errno should be ENOMEM > > when the specific [addr+len] exceeds the bound of memory. The mmap() function may fail if: [EINVAL] The addr argument (if MAP_FIXED was specified) or off is not a multiple of the page size as returned by sysconf(), or is considered invalid by ^^^^^^^^^^^^^^^^^^^^^^^^^^^ the implementation. ^^^^^^^^^^^^^^^^^^^ So that behaviour gets past POSIX. That part is mostly about the things like cache aliasing constraints, etc., but it leaves enough space to weasel out. Said that, this [ENOMEM] MAP_FIXED was specified, and the range [addr,addr+len) exceeds that allowed for the address space of a process; or, if MAP_FIXED was not specified and there is insufficient room in the address space to effect the mapping. is a lot more specific, so switching to -ENOMEM there might be a good idea, especially since on other architectures we do get -ENOMEM in that case, AFAICS.
