hpfs: hpfs_error: Remove static buffer, use vsprintf extension %pV instead

commit a28e4b2b upstream.

Removing unnecessary static buffers is good.
Use the vsprintf %pV extension instead.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Mikulas Patocka <mikulas@twibright.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[Mikulas:
 - The bug corrected by the patch is - if hpfs_error is called concurrently
   on multiple filesystems, it could corrupt the string because the text
   buffer is shared. That's why I marked the patch for stable.]
[lizf: Backported to 3.4: adjust context]
Signed-off-by: Zefan Li <lizefan@huawei.com>

fs/hpfs/super.c

@@ -52,17 +52,20 @@ static void unmark_dirty(struct super_block *s)
 }
 
 /* Filesystem error... */
-static char err_buf[1024];
-
 void hpfs_error(struct super_block *s, const char *fmt, ...)
 {
+	struct va_format vaf;
 	va_list args;
 
 	va_start(args, fmt);
-	vsnprintf(err_buf, sizeof(err_buf), fmt, args);
+
+	vaf.fmt = fmt;
+	vaf.va = &args;
+
+	pr_err("filesystem error: %pV", &vaf);
+
 	va_end(args);
 
-	printk("HPFS: filesystem error: %s", err_buf);
 	if (!hpfs_sb(s)->sb_was_error) {
 		if (hpfs_sb(s)->sb_err == 2) {
 			printk("; crashing the system because you wanted it\n");