[LTP] [PATCH] hugeshmctl02: Skipped EFAULT tests for libc variant

[Dylan Dai-Rong Jhong(鍾岱融)]

Hi All,

Ping. Any comments on this patch?

Thanks,
Dylan

-----Original Message-----
From: Dylan Dai-Rong Jhong(鍾岱融) <dylan@andestech.com>
Sent: Thursday, June 15, 2023 5:40 PM
To: ltp@lists.linux.it
Cc: Randolph Sheng-Kai Lin(林聖凱) <randolph@andestech.com>; x5710999x@gmail.com; Tim Shih-Ting OuYang(歐陽士庭) <tim609@andestech.com>; Mina Hui-Min Chou(周慧敏) <minachou@andestech.com>; Dylan Dai-Rong Jhong(鍾岱融) <dylan@andestech.com>
Subject: [LTP] [PATCH] hugeshmctl02: Skipped EFAULT tests for libc variant

When testing hugeshmctl02 under the 32bit architecture, a segmentation fault will occur. This patch will skip EFAULT tests for libc variant.

Hugeshmctl02 will intentionally pass "(struct shmid_ds *)-1" to shmctl(), but glibc will perform an additional conversion function when the architecture is 32bit, which will try to copy all items in (struct shmid_ds *) to another structure[*1]. In the process of copying, it is necessary to dereference "(struct shmid_ds *)-1", resulting in segmentation fault.

The LTP also has similar problems before, this patch is reference from the
shmctl03 patch[*2].

[*1]: https://github.com/bminor/glibc/blob/master/sysdeps/unix/sysv/linux/shmctl.c#L37
[*2]: https://github.com/linux-test-project/ltp/commit/a5a80aa8485a7cb017f96aba8d7b5ea79f1ba4d4

Signed-off-by: Dylan Jhong <dylan@andestech.com>
---
 .../mem/hugetlb/hugeshmctl/hugeshmctl02.c     | 35 ++++++++++++++++++-
 1 file changed, 34 insertions(+), 1 deletion(-)

diff --git a/testcases/kernel/mem/hugetlb/hugeshmctl/hugeshmctl02.c b/testcases/kernel/mem/hugetlb/hugeshmctl/hugeshmctl02.c
index 0bc9ffd74..e9c2e9fc8 100644
--- a/testcases/kernel/mem/hugetlb/hugeshmctl/hugeshmctl02.c
+++ b/testcases/kernel/mem/hugetlb/hugeshmctl/hugeshmctl02.c
@@ -27,6 +27,7 @@
 #include <pwd.h>
 #include <limits.h>
 #include "hugetlb.h"
+#include "lapi/syscalls.h"

 static size_t shm_size;
 static int shm_id_1 = -1;
@@ -50,9 +51,37 @@ struct tcase {
        {&shm_id_2, -1, &buf, EINVAL},
 };

+static int libc_shmctl(int shmid, int cmd, void *buf) {
+       return shmctl(shmid, cmd, buf);
+}
+
+static int sys_shmctl(int shmid, int cmd, void *buf) {
+       return tst_syscall(__NR_shmctl, shmid, cmd, buf); }
+
+static struct test_variants
+{
+       int (*shmctl)(int shmid, int cmd, void *buf);
+       char *desc;
+} variants[] = {
+       { .shmctl = libc_shmctl, .desc = "libc shmctl()"}, #if (__NR_shmctl !=
+__LTP__NR_INVALID_SYSCALL)
+       { .shmctl = sys_shmctl,  .desc = "__NR_shmctl syscall"}, #endif };
+
 static void test_hugeshmctl(unsigned int i)  {
-       TEST(shmctl(*(tcases[i].shmid), tcases[i].cmd, tcases[i].sbuf));
+       struct test_variants *tv = &variants[tst_variant];
+
+       if (tcases[i].error == EFAULT && tv->shmctl == libc_shmctl) {
+               tst_res(TCONF, "EFAULT is skipped for libc variant");
+               return;
+       }
+
+       TEST(tv->shmctl(*(tcases[i].shmid), tcases[i].cmd, tcases[i].sbuf));
        if (TST_RET != -1) {
                tst_res(TFAIL, "shmctl succeeded unexpectedly");
                return;
@@ -70,8 +99,11 @@ static void test_hugeshmctl(unsigned int i)

 static void setup(void)
 {
+       struct test_variants *tv = &variants[tst_variant];
        long hpage_size;

+       tst_res(TINFO, "Testing variant: %s", tv->desc);
+
        if (tst_hugepages == 0)
                tst_brk(TCONF, "No enough hugepages for testing.");

@@ -101,6 +133,7 @@ static void cleanup(void)

 static struct tst_test test = {
        .test = test_hugeshmctl,
+       .test_variants = ARRAY_SIZE(variants),
        .tcnt = ARRAY_SIZE(tcases),
        .needs_root = 1,
        .needs_tmpdir = 1,
--
2.34.1

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