Quoting Chris Wilson (2020-08-06 15:35:36) > When igt_random_offset() is a given a range of [0, PAGE_SIZE], it is > allowed to return 0. However, attempting to use a size of 0 for the > igt_lmem_write_cpu() byte poking, leads to call igt_random_offset() with > a range of [offset, offset + 0] and ask it to find a length of 4 within > it. This triggers the bug on that the requested length should fit within > the range! > > Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > Cc: Matthew Auld <matthew.auld@xxxxxxxxx> > --- > I feel into the same trap of not fixing up the random return of 0 > --- > drivers/gpu/drm/i915/selftests/intel_memory_region.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/i915/selftests/intel_memory_region.c b/drivers/gpu/drm/i915/selftests/intel_memory_region.c > index 6e80d99048e4..54e683bb220b 100644 > --- a/drivers/gpu/drm/i915/selftests/intel_memory_region.c > +++ b/drivers/gpu/drm/i915/selftests/intel_memory_region.c > @@ -522,9 +522,10 @@ static int igt_lmem_write_cpu(void *arg) > goto out_unpin; > } > > - /* We want to throw in a random width/align */ > - bytes[0] = igt_random_offset(&prng, 0, PAGE_SIZE, sizeof(u32), > - sizeof(u32)); > + /* A random multiple of u32, picked between [64, PAGE_SIZE - 64] */ > + bytes[0] = 1 + prandom_u32_state(&prng); But what about if it returns -1. Gah. -Chris _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
