On Mon, Jul 26, 2021 at 9:16 AM Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > > From: Peter Collingbourne <pcc@xxxxxxxxxx> > > commit 0db282ba2c12c1515d490d14a1ff696643ab0f1b upstream. > > This test passes pointers obtained from anon_allocate_area to the > userfaultfd and mremap APIs. This causes a problem if the system > allocator returns tagged pointers because with the tagged address ABI > the kernel rejects tagged addresses passed to these APIs, which would > end up causing the test to fail. To make this test compatible with such > system allocators, stop using the system allocator to allocate memory in > anon_allocate_area, and instead just use mmap. > > Link: https://lkml.kernel.org/r/20210714195437.118982-3-pcc@xxxxxxxxxx > Link: https://linux-review.googlesource.com/id/Icac91064fcd923f77a83e8e133f8631c5b8fc241 > Fixes: c47174fc362a ("userfaultfd: selftest") > Co-developed-by: Lokesh Gidra <lokeshgidra@xxxxxxxxxx> > Signed-off-by: Lokesh Gidra <lokeshgidra@xxxxxxxxxx> > Signed-off-by: Peter Collingbourne <pcc@xxxxxxxxxx> > Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx> > Cc: Vincenzo Frascino <vincenzo.frascino@xxxxxxx> > Cc: Dave Martin <Dave.Martin@xxxxxxx> > Cc: Will Deacon <will@xxxxxxxxxx> > Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx> > Cc: Alistair Delva <adelva@xxxxxxxxxx> > Cc: William McVicker <willmcvicker@xxxxxxxxxx> > Cc: Evgenii Stepanov <eugenis@xxxxxxxxxx> > Cc: Mitch Phillips <mitchp@xxxxxxxxxx> > Cc: Andrey Konovalov <andreyknvl@xxxxxxxxx> > Cc: <stable@xxxxxxxxxxxxxxx> [5.4] > Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > --- > tools/testing/selftests/vm/userfaultfd.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > --- a/tools/testing/selftests/vm/userfaultfd.c > +++ b/tools/testing/selftests/vm/userfaultfd.c > @@ -197,8 +197,10 @@ static int anon_release_pages(char *rel_ > > static void anon_allocate_area(void **alloc_area) > { > - if (posix_memalign(alloc_area, page_size, nr_pages * page_size)) { > - fprintf(stderr, "out of memory\n"); > + *alloc_area = mmap(NULL, nr_pages * page_size, PROT_READ | PROT_WRITE, > + MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); > + if (*alloc_area == MAP_FAILED) Hi Greg, It looks like your backport of this patch (and the backports to stable kernels) are missing a left brace here. Peter > + fprintf(stderr, "mmap of anonymous memory failed"); > *alloc_area = NULL; > } > } > >
