Re: [LTP] [PATCH 1/1] recvmmsg01: Workaround segfault on libc variant on 32 bit

Wei Gao via ltp
2024-11-11T08:31:13Z

On Fri, Nov 08, 2024 at 01:21:39PM +0100, Petr Vorel wrote:
> EFAULT test segfaults on newer kernels (e.g. 6.4) on libc variant on
> 32bit. Use typical LTP workaround to test by forked child + checking
> the terminating signal.
>
> NOTE: testing kernel variants could be done without forking child, but
> use it as well for simplicity.
>
> Suggested-by: Cyril Hrubis <chrubis@suse.cz>
> Signed-off-by: Petr Vorel <pvorel@suse.cz>
> ---
> NOTE: working on other 3 tests affected by the same problem
> (mq_timedreceive01.c, mq_timedsend01.c, sigtimedwait01.c).
>
> .../kernel/syscalls/recvmmsg/recvmmsg01.c | 48 +++++++++++++++----
> 1 file changed, 40 insertions(+), 8 deletions(-)
>
> diff --git a/testcases/kernel/syscalls/recvmmsg/recvmmsg01.c b/testcases/kernel/syscalls/recvmmsg/recvmmsg01.c
> index fb21ea1e70..46658b133d 100644
> --- a/testcases/kernel/syscalls/recvmmsg/recvmmsg01.c
> +++ b/testcases/kernel/syscalls/recvmmsg/recvmmsg01.c
> @@ -47,7 +47,7 @@ static struct test_case tcase[] = {
> .desc = "bad message vector address",
> .fd = &receive_sockfd,
> .exp_errno = EFAULT,
> - .msg_vec = (void*)&bad_addr,
> + .msg_vec = (void *)&bad_addr,
> },
> {
> .desc = "negative seconds in timeout",
> @@ -74,23 +74,54 @@ static struct test_case tcase[] = {
> }
> };
>
> -static void do_test(unsigned int i)
> +static void verify_recvmmsg(unsigned int i, void *timeout)
> {
> struct time64_variants *tv = &variants[tst_variant];
> struct test_case *tc = &tcase[i];
> - void *timeout;
>
> ts.type = tv->ts_type;
> tst_ts_set_sec(&ts, tc->tv_sec);
> tst_ts_set_nsec(&ts, tc->tv_nsec);
>
> + TST_EXP_FAIL2(tv->recvmmsg(*tc->fd, *tc->msg_vec, VLEN, 0, timeout),
> + tc->exp_errno, "recvmmsg() %s", tc->desc);
> +}
> +
> +static void test_bad_addr(unsigned int i)
> +{
> + struct time64_variants *tv = &variants[tst_variant];
> + void *timeout = bad_addr;
> + pid_t pid;
> + int status;
> +
> + pid = SAFE_FORK();
> + if (!pid) {
> + verify_recvmmsg(i, timeout);
> + _exit(!TST_PASS);
> + }
> +
> + SAFE_WAITPID(pid, &status, 0);
> +
> + if (WIFEXITED(status))
> + return;
> +
> + if (tv->ts_type == TST_LIBC_TIMESPEC &&
> + WIFSIGNALED(status) && WTERMSIG(status) == SIGSEGV) {
> + tst_res(TPASS, "Child killed by signal");
very nit:
1) s/Child killed by signal/Child killed by SIGSEGV signal/
2) suggest also print out tc->desc

Thanks for create patch fix our current issue.
Reviewed-by: Wei Gao <wegao@suse.com>
> + return;
> + }
> +
> + tst_res(TFAIL, "Child %s", tst_strstatus(status));
> +}
> +
> +static void do_test(unsigned int i)
> +{
> + struct test_case *tc = &tcase[i];
> +
> if (tc->bad_ts_addr)
> - timeout = bad_addr;
> + test_bad_addr(i);
> else
> - timeout = tst_ts_get(&ts);
> -
> - TST_EXP_FAIL2(tv->recvmmsg(*tc->fd, *tc->msg_vec, VLEN, 0, timeout),
> - tc->exp_errno, "recvmmsg() %s", tc->desc);
> + verify_recvmmsg(i, tst_ts_get(&ts));
> }
>
> static void setup(void)
> @@ -139,6 +170,7 @@ static struct tst_test test = {
> .setup = setup,
> .cleanup = cleanup,
> .test_variants = ARRAY_SIZE(variants),
> + .forks_child = 1,
> .bufs = (struct tst_buffers []) {
> {&iov, .iov_sizes = (int[]){1, -1}},
> {&msg, .size = VLEN * sizeof(*msg)},
> --
> 2.45.2
>