fs/procfs: remove build ID-related code duplication in PROCMAP_QUERY

A piece of build ID handling code in PROCMAP_QUERY ioctl() was
accidentally duplicated.  It wasn't meant to be part of ed5d583a
("fs/procfs: implement efficient VMA querying API for /proc/<pid>/maps")
commit, which is what introduced duplication.

It has no correctness implications, but we unnecessarily perform the same
work twice, if build ID parsing is requested.  Drop the duplication.

Link: https://lkml.kernel.org/r/20240729174044.4008399-1-andrii@kernel.org
Fixes: ed5d583a ("fs/procfs: implement efficient VMA querying API for /proc/<pid>/maps")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reported-by: Jann Horn <jannh@google.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

fs/proc/task_mmu.c

@@ -543,21 +543,6 @@ static int do_procmap_query(struct proc_maps_private *priv, void __user *uarg)
 		}
 	}
 
-	if (karg.build_id_size) {
-		__u32 build_id_sz;
-
-		err = build_id_parse(vma, build_id_buf, &build_id_sz);
-		if (err) {
-			karg.build_id_size = 0;
-		} else {
-			if (karg.build_id_size < build_id_sz) {
-				err = -ENAMETOOLONG;
-				goto out;
-			}
-			karg.build_id_size = build_id_sz;
-		}
-	}
-
 	if (karg.vma_name_size) {
 		size_t name_buf_sz = min_t(size_t, PATH_MAX, karg.vma_name_size);
 		const struct path *path;