Hi Al, On Thu, Oct 18, 2018 at 05:32:00AM +0100, Al Viro wrote: > [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. Thanks for the heads up - that does sound like reasonably clear non-compliance. I'll make a note to put together a patch & test it out, likely next week, if nobody submits one first. Thanks, Paul
