[LTP] [PATCH] syscalls/pread02: extend buffer to avoid glibc overflow detection

[Jan Stancek]

Test started failing with recent glibc (glibc-2.34.9000-38.fc36),
which detects that buffer in pread is potentially too small:
  tst_test.c:1431: TINFO: Timeout per run is 0h 05m 00s
  *** buffer overflow detected ***: terminated
  tst_test.c:1484: TBROK: Test killed by SIGIOT/SIGABRT!

(gdb) bt
  #0  __pthread_kill_implementation at pthread_kill.c:44
  #1  0x00007ffff7e46f73 in __pthread_kill_internal at pthread_kill.c:78
  #2  0x00007ffff7df6a36 in __GI_raise at ../sysdeps/posix/raise.c:26
  #3  0x00007ffff7de082f in __GI_abort () at abort.c:79
  #4  0x00007ffff7e3b01e in __libc_message at ../sysdeps/posix/libc_fatal.c:155
  #5  0x00007ffff7ed945a in __GI___fortify_fail at fortify_fail.c:26
  #6  0x00007ffff7ed7dc6 in __GI___chk_fail () at chk_fail.c:28
  #7  0x00007ffff7ed8214 in __pread_chk at pread_chk.c:26
  #8  0x0000000000404d1a in pread at /usr/include/bits/unistd.h:74
  #9  verify_pread (n=<optimized out>) at pread02.c:44
  #10 0x000000000040dc19 in run_tests () at tst_test.c:1246
  #11 testrun () at tst_test.c:1331
  #12 fork_testrun () at tst_test.c:1462
  #13 0x000000000040e9a1 in tst_run_tcases
  #14 0x0000000000404bde in main

Extend it to number of bytes we are trying to read from fd.

Signed-off-by: Jan Stancek <jstancek@redhat.com>
---
 testcases/kernel/syscalls/pread/pread02.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/testcases/kernel/syscalls/pread/pread02.c b/testcases/kernel/syscalls/pread/pread02.c
index de2a81fffc37..fda5fd19037c 100644
--- a/testcases/kernel/syscalls/pread/pread02.c
+++ b/testcases/kernel/syscalls/pread/pread02.c
@@ -39,7 +39,7 @@ struct test_case_t {
 static void verify_pread(unsigned int n)
 {
 	struct test_case_t *tc = &tcases[n];
-	char buf;
+	char buf[K1];
 
 	TST_EXP_FAIL2(pread(*tc->fd, &buf, tc->nb, tc->offst), tc->exp_errno,
 		"pread(%d, %zu, %ld) %s", *tc->fd, tc->nb, tc->offst, tc->desc);
-- 
2.27.0