File ioctl_sg01_Print_buffer_contents_on_failure.patch of Package ltp-stable

From 728c97429e6a3ca9cb3bab33760c58fe3cac9dc9 Mon Sep 17 00:00:00 2001
From: Martin Doucha <mdoucha@suse.cz>
Date: Wed, 22 Oct 2025 11:57:38 +0200
Subject: [PATCH] ioctl_sg01: Print buffer contents on failure

Link: https://lore.kernel.org/ltp/20251022095740.8747-2-mdoucha@suse.cz/
Tested-by: Petr Vorel <pvorel@suse.cz>
Reviewed-by: Petr Vorel <pvorel@suse.cz>
Signed-off-by: Martin Doucha <mdoucha@suse.cz>
---
 testcases/kernel/syscalls/ioctl/ioctl_sg01.c | 24 +++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/testcases/kernel/syscalls/ioctl/ioctl_sg01.c b/testcases/kernel/syscalls/ioctl/ioctl_sg01.c
index 66ff980ce59..dada174e007 100644
--- a/testcases/kernel/syscalls/ioctl/ioctl_sg01.c
+++ b/testcases/kernel/syscalls/ioctl/ioctl_sg01.c
@@ -36,7 +36,7 @@
 #define CMD_SIZE 6
 
 static int devfd = -1;
-static char buffer[BUF_SIZE];
+static char buffer[BUF_SIZE + 1];
 static unsigned char command[CMD_SIZE];
 static struct sg_io_hdr query;
 
@@ -100,6 +100,25 @@ static const char *find_generic_scsi_device(int access_flags, int skip_usb)
 	return NULL;
 }
 
+static void dump_hex(const char *str, size_t size)
+{
+	size_t i;
+
+	for (; size && !str[size - 1]; size--)
+		;
+
+	for (i = 0; i < size; i++) {
+		if (i && (i % 32) == 0)
+			printf("\n");
+		else if (i && (i % 4) == 0)
+			printf(" ");
+
+		printf("%02x", (unsigned int)str[i]);
+	}
+
+	printf("\n");
+}
+
 static void setup(void)
 {
 	const char *devpath = find_generic_scsi_device(O_RDONLY, 1);
@@ -135,6 +154,7 @@ static void run(void)
 
 	for (i = 0; i < 100; i++) {
 		TEST(ioctl(devfd, SG_IO, &query));
+		buffer[BUF_SIZE] = '\0';
 
 		if (TST_RET != 0 && TST_RET != -1)
 			tst_brk(TBROK|TTERRNO, "Invalid ioctl() return value");
@@ -143,6 +163,8 @@ static void run(void)
 		for (j = 0; j < BUF_SIZE; j++) {
 			if (buffer[j]) {
 				tst_res(TFAIL, "Kernel memory leaked");
+				tst_res(TINFO, "Buffer contents: %s", buffer);
+				dump_hex(buffer, BUF_SIZE);
 				return;
 			}
 		}