On Thu, May 09, 2019 at 01:05:55PM -0700, Nadav Amit wrote: > One of the most important properties of tests is reproducibility. For > tests to be reproducible, the same environment should be set on each > test invocation. > > When it comes to memory content, this is not exactly the case in > kvm-unit-tests. The tests might, mistakenly or intentionally, assume > that memory is zeroed (by the BIOS or KVM). However, failures might not > be reproducible if this assumption is broken. > > As an example, consider x86 do_iret(), which mistakenly does not push > SS:RSP onto the stack on 64-bit mode, although they are popped > unconditionally on iret. > > Do not assume that memory is zeroed. Clear it once it is allocated to > allow tests to easily be reproduced. > > Reviewed-by: Krish Sadhukhan <krish.sadhukhan@xxxxxxxxxx> > Signed-off-by: Nadav Amit <nadav.amit@xxxxxxxxx> > --- > lib/alloc_page.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/lib/alloc_page.c b/lib/alloc_page.c > index 730f2b5..97d1339 100644 > --- a/lib/alloc_page.c > +++ b/lib/alloc_page.c > @@ -65,6 +65,8 @@ void *alloc_page() > freelist = *(void **)freelist; > spin_unlock(&lock); > > + if (p) > + memset(p, 0, PAGE_SIZE); > return p; > } > > @@ -126,6 +128,8 @@ void *alloc_pages(unsigned long order) > } > } > spin_unlock(&lock); > + if (run_start) > + memset(run_start, 0, n * PAGE_SIZE); > return run_start; > } > > -- > 2.17.1 > Reviewed-by: Andrew Jones <drjones@xxxxxxxxxx>
