mountpoint-util: initialize mnt_id for name_to_handle_at(AT_HANDLE_MNT_ID_UNIQUE)

Suppress the following message:
```
$ sudo valgrind --leak-check=full build/networkctl dhcp-lease wlp59s0
==175708== Memcheck, a memory error detector
==175708== Copyright (C) 2002-2024, and GNU GPL'd, by Julian Seward et al.
==175708== Using Valgrind-3.26.0 and LibVEX; rerun with -h for copyright info
==175708== Command: build/networkctl status wlp59s0
==175708==
==175708== Conditional jump or move depends on uninitialised value(s)
==175708==    at 0x4BC33D1: inode_same_at (stat-util.c:610)
==175708==    by 0x4BF1972: inode_same (stat-util.h:86)
==175708==    by 0x4BF48FE: running_in_chroot (virt.c:817)
==175708==    by 0x4B16643: running_in_chroot_or_offline (verbs.c:37)
==175708==    by 0x4B175CE: _dispatch_verb_with_args (verbs.c:136)
==175708==    by 0x4B17868: dispatch_verb (verbs.c:160)
==175708==    by 0x407CBB: networkctl_main (networkctl.c:249)
==175708==    by 0x407D06: run (networkctl.c:263)
==175708==    by 0x407D39: main (networkctl.c:266)
==175708==
```
Not sure if it is an issue in valgrind or glibc, but at least there is
nothing we can do except for working around it.

(cherry picked from commit f46ad8b4ba8a5aef0bb628bd5dcd7ec43283e9a1)

diff --git a/src/basic/mountpoint-util.c b/src/basic/mountpoint-util.c
index 79b51cb099fcde15c03697e8fe5836286e1b2786..e5781e44cf010912531ef5da4d2720ec582977c4 100644 (file)
--- a/src/basic/mountpoint-util.c
+++ b/src/basic/mountpoint-util.c
@@ -84,7 +84,13 @@ int name_to_handle_at_loop(
                 h->handle_bytes = n;
 
                 if (ret_unique_mnt_id) {
-                        uint64_t mnt_id;
+                        /* Here, explicitly initialize mnt_id, otherwise valgrind complains:
+                         *
+                         * ==175708== Conditional jump or move depends on uninitialised value(s)
+                         * ==175708==    at 0x4BC33D1: inode_same_at (stat-util.c:610)
+                         * ==175708==    by 0x4BF1972: inode_same (stat-util.h:86)
+                         */
+                        uint64_t mnt_id = 0;
 
                         /* The kernel will still use this as uint64_t pointer */
                         r = name_to_handle_at(fd, path, h, (int *) &mnt_id, flags|AT_HANDLE_MNT_ID_UNIQUE);