On Fri, Aug 30, 2019 at 03:29:29PM +0100, Cristian Marussi wrote:
> Hi
>
> On 13/08/2019 17:25, Dave Martin wrote:
> > On Fri, Aug 02, 2019 at 06:02:55PM +0100, Cristian Marussi wrote:
[...]
> >> diff --git a/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_magic.c b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_magic.c
[...]
> >> +static int fake_sigreturn_bad_magic_run(struct tdescr *td,
> >> + siginfo_t *si, ucontext_t *uc)
> >> +{
> >> + size_t resv_sz, offset;
> >> + struct _aarch64_ctx *shead = GET_SF_RESV_HEAD(sf), *head;
> >> +
> >> + /* just to fill the ucontext_t with something real */
> >> + if (!get_current_context(td, &sf.uc))
> >> + return 1;
> >> +
> >> + resv_sz = GET_SF_RESV_SIZE(sf);
> >> + /*
> >> + * find the terminator, preserving existing headers
> >> + * and verify amount of spare room in __reserved area.
> >> + */
> >> + head = get_terminator(shead, resv_sz, &offset);
> >> + /*
> >> + * try stripping extra_context header when low on space:
> >> + * we need at least 2*HDR_SZ space ... one for the KSFT_BAD_MAGIC
> >> + * and the other for the usual terminator.
> >> + */
> >> + if (head && resv_sz - offset < HDR_SZ * 2) {
> >
> > Can we factor out this logic for finding space in the signal frame?
> >
> > We do pretty much the same thing in all the fake_sigreturn tests...
>
> Ok
> >
> >> + fprintf(stderr, "Low on space:%zd. Discarding extra_context.\n",
> >> + resv_sz - offset);
> >> + head = get_header(shead, EXTRA_MAGIC, resv_sz, &offset);
> >> + }
> >> + /* just give up and timeout if still not enough space */
> >
> > Do we actually time out? I don't see where we actually wait, so doesn't
> > test_run() just fail immediately?
> >
> > The same applies to all the other fake_sigreturn tests too.
> >
> Right. It is probably a leftover.
>
> SIGALRM is used as an extreme measure to kill tests gone bad, but this
> can happen only once the fake sigframe has been effectively placed on the stack
> and sigreturned.
OK, so this gets reported as a test failure because with no SIGSEGV,
nothing ever sets td->pass?
This is probably OK for now, though I wonder whether this should be
reported as a skipped test instead.
In case of doubt, reporting a failure is preferable anyway, since that
will encourage people actually to investigate what went wrong.
[...]
Cheers
---Dave
