On Thu, Mar 26, 2015 at 10:08 AM, Eric B Munson <emunson@xxxxxxxxxx> wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > On 03/26/2015 07:56 AM, Davide Libenzi wrote: >> On Wed, 25 Mar 2015, David Rientjes wrote: >> >>> I looked at this thread at http://marc.info/?t=141392508800001 >>> since I didn't have it in my mailbox, and I didn't get a chance >>> to actually run your test code. >>> >>> In short, I think what you're saying is that >>> >>> ptr = mmap(..., 4KB, ..., MAP_HUGETLB | ..., ...) munmap(ptr, >>> 4KB) == EINVAL >> >> I am not sure you have read the email correctly: >> >> munmap(mmap(size, HUGETLB), size) = EFAIL >> >> For every size not multiple of the huge page size. Whereas: >> >> munmap(mmap(size, HUGETLB), ALIGN(size, HUGEPAGE_SIZE)) = OK > > I think Davide is right here, this is a long existing bug in the > MAP_HUGETLB implementation. Specifically, the mmap man page says: > > All pages containing a part of the indicated range are unmapped, and > subsequent references to these pages will generate SIGSEGV. > > I realize that huge pages may not have been considered by those that > wrote the spec. But if I read this I would assume that all pages, > regardless of size, touched by the munmap() request should be unmapped. > > Please include > Acked-by: Eric B Munson <emunson@xxxxxxxxxx> > to the original patch. I would like to see the mmap man page adjusted > to make note of this behavior as well. This is just a bug fix and I never think this has large risk. But caution, we might revert immediately if this patch arise some regression even if it's come from broken application code. Acked-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxx> -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>