Re: [LTP] [PATCH v1] mseal02: Handle multiple errnos for 32-bit compat mode

Cyril Hrubis
2026-02-19T11:38:08Z

Hi!
> > In 32-bit compat mode, the overflow_size (calculated using a 32-bit ULONG_MAX)
> > does not cause a 64-bit integer wrap-around when added to the start address.
> > Consequently, the kernel see valid range that points to unmapped space, returning
> > ENOMEM instead of the expected EINVAL.
> >
> > Signed-off-by: Wei Gao <wegao@suse.com>
> > ---
> > testcases/kernel/syscalls/mseal/mseal02.c | 20 +++++++++++---------
> > 1 file changed, 11 insertions(+), 9 deletions(-)
> >
> > diff --git a/testcases/kernel/syscalls/mseal/mseal02.c b/testcases/kernel/syscalls/mseal/mseal02.c
> > index e11d7dbf4..d941f6c40 100644
> > --- a/testcases/kernel/syscalls/mseal/mseal02.c
> > +++ b/testcases/kernel/syscalls/mseal/mseal02.c
> > @@ -21,6 +21,8 @@
> > #include "tst_test.h"
> > #include "lapi/syscalls.h"
> >
> > +#define MAX_ERRNOS 5
> > +
> > static void *start_addr, *unaligned_start_addr, *unallocated_start_addr, *unallocated_end_addr;
> > static size_t page_size, twopages_size, fourpages_size, overflow_size;
> >
> > @@ -28,22 +30,22 @@ static struct tcase {
> > void **addr;
> > size_t *len;
> > unsigned long flags;
> > - int exp_err;
> > + int exp_errs[MAX_ERRNOS];
> > } tcases[] = {
> > - {&start_addr, &page_size, ULONG_MAX, EINVAL},
> > - {&unaligned_start_addr, &page_size, 0, EINVAL},
> > - {&start_addr, &overflow_size, 0, EINVAL},
> > - {&unallocated_start_addr, &twopages_size, 0, ENOMEM},
> > - {&unallocated_end_addr, &twopages_size, 0, ENOMEM},
> > - {&start_addr, &fourpages_size, 0, ENOMEM},
> > + {&start_addr, &page_size, ULONG_MAX, {EINVAL}},
> > + {&unaligned_start_addr, &page_size, 0, {EINVAL}},
> > + {&start_addr, &overflow_size, 0, {EINVAL, ENOMEM}},
> > + {&unallocated_start_addr, &twopages_size, 0, {ENOMEM}},
> > + {&unallocated_end_addr, &twopages_size, 0, {ENOMEM}},
> > + {&start_addr, &fourpages_size, 0, {ENOMEM}},
> > };
> >
> > static void run(unsigned int n)
> > {
> > struct tcase *tc = &tcases[n];
> >
> > - TST_EXP_FAIL(tst_syscall(__NR_mseal, *tc->addr, *tc->len, tc->flags), tc->exp_err,
> > - "mseal(%p, %lu, %lu)", *tc->addr, *tc->len, tc->flags);
> > + TST_EXP_FAIL2_ARR(tst_syscall(__NR_mseal, *tc->addr, *tc->len, tc->flags),
> > + tc->exp_errs, MAX_ERRNOS, "mseal(%p, %lu, %lu)", *tc->addr, *tc->len, tc->flags);
> > }
> >
> > static void setup(void)
>
> Instead of checking multiple errno, you should pass the right type
> according to the architecture.

That would be slightly more complex here since the problem happens only
in compat mode, which can be only detected at runtime with
tst_is_compat_mode(). We would have to call that in the test setup and
adjust expectations accordinlgy.

--
Cyril Hrubis
chrubis@suse.cz