505ca8
From f58b96d3e8d1cb0dd3666bc74fa673918b586612 Mon Sep 17 00:00:00 2001
505ca8
From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= <zbyszek@in.waw.pl>
505ca8
Date: Mon, 14 Sep 2020 17:58:03 +0200
505ca8
Subject: [PATCH] test-mountpointutil-util: do not assert in test_mnt_id()
505ca8
505ca8
https://bugzilla.redhat.com/show_bug.cgi?id=1803070
505ca8
505ca8
I *think* this a kernel bug: the mnt_id as listed in /proc/self/mountinfo is different
505ca8
than the one we get from /proc/self/fdinfo/. This only matters when both statx and
505ca8
name_to_handle_at are unavailable and we hit the fallback path that goes through fdinfo:
505ca8
505ca8
(gdb) !uname -r
505ca8
5.6.19-200.fc31.ppc64le
505ca8
505ca8
(gdb) !cat /proc/self/mountinfo
505ca8
697 664 253:0 /var/lib/mock/fedora-31-ppc64le/root / rw,relatime shared:298 master:1 - xfs /dev/mapper/fedora_rh--power--vm14-root rw,seclabel,attr2,inode64,logbufs=8,logbsize=32k,noquota
505ca8
698 697 253:0 /var/cache/mock/fedora-31-ppc64le/yum_cache /var/cache/yum rw,relatime shared:299 master:1 - xfs /dev/mapper/fedora_rh--power--vm14-root rw,seclabel,attr2,inode64,logbufs=8,logbsize=32k,noquota
505ca8
699 697 253:0 /var/cache/mock/fedora-31-ppc64le/dnf_cache /var/cache/dnf rw,relatime shared:300 master:1 - xfs /dev/mapper/fedora_rh--power--vm14-root rw,seclabel,attr2,inode64,logbufs=8,logbsize=32k,noquota
505ca8
700 697 0:32 /mock-selinux-plugin.7me9bfpi /proc/filesystems rw,nosuid,nodev shared:301 master:18 - tmpfs tmpfs rw,seclabel <==========================================================
505ca8
701 697 0:41 / /sys ro,nosuid,nodev,noexec,relatime shared:302 - sysfs sysfs ro,seclabel
505ca8
702 701 0:21 / /sys/fs/selinux ro,nosuid,nodev,noexec,relatime shared:306 master:8 - selinuxfs selinuxfs rw
505ca8
703 697 0:42 / /dev rw,nosuid shared:303 - tmpfs tmpfs rw,seclabel,mode=755
505ca8
704 703 0:43 / /dev/shm rw,nosuid,nodev shared:304 - tmpfs tmpfs rw,seclabel
505ca8
705 703 0:45 / /dev/pts rw,nosuid,noexec,relatime shared:307 - devpts devpts rw,seclabel,gid=5,mode=620,ptmxmode=666
505ca8
706 703 0:6 /btrfs-control /dev/btrfs-control rw,nosuid shared:308 master:9 - devtmpfs devtmpfs rw,seclabel,size=4107840k,nr_inodes=64185,mode=755
505ca8
707 703 0:6 /loop-control /dev/loop-control rw,nosuid shared:309 master:9 - devtmpfs devtmpfs rw,seclabel,size=4107840k,nr_inodes=64185,mode=755
505ca8
708 703 0:6 /loop0 /dev/loop0 rw,nosuid shared:310 master:9 - devtmpfs devtmpfs rw,seclabel,size=4107840k,nr_inodes=64185,mode=755
505ca8
709 703 0:6 /loop1 /dev/loop1 rw,nosuid shared:311 master:9 - devtmpfs devtmpfs rw,seclabel,size=4107840k,nr_inodes=64185,mode=755
505ca8
710 703 0:6 /loop10 /dev/loop10 rw,nosuid shared:312 master:9 - devtmpfs devtmpfs rw,seclabel,size=4107840k,nr_inodes=64185,mode=755
505ca8
711 703 0:6 /loop11 /dev/loop11 rw,nosuid shared:313 master:9 - devtmpfs devtmpfs rw,seclabel,size=4107840k,nr_inodes=64185,mode=755
505ca8
712 703 0:6 /loop2 /dev/loop2 rw,nosuid shared:314 master:9 - devtmpfs devtmpfs rw,seclabel,size=4107840k,nr_inodes=64185,mode=755
505ca8
713 703 0:6 /loop3 /dev/loop3 rw,nosuid shared:315 master:9 - devtmpfs devtmpfs rw,seclabel,size=4107840k,nr_inodes=64185,mode=755
505ca8
714 703 0:6 /loop4 /dev/loop4 rw,nosuid shared:316 master:9 - devtmpfs devtmpfs rw,seclabel,size=4107840k,nr_inodes=64185,mode=755
505ca8
715 703 0:6 /loop5 /dev/loop5 rw,nosuid shared:317 master:9 - devtmpfs devtmpfs rw,seclabel,size=4107840k,nr_inodes=64185,mode=755
505ca8
716 703 0:6 /loop6 /dev/loop6 rw,nosuid shared:318 master:9 - devtmpfs devtmpfs rw,seclabel,size=4107840k,nr_inodes=64185,mode=755
505ca8
717 703 0:6 /loop7 /dev/loop7 rw,nosuid shared:319 master:9 - devtmpfs devtmpfs rw,seclabel,size=4107840k,nr_inodes=64185,mode=755
505ca8
718 703 0:6 /loop8 /dev/loop8 rw,nosuid shared:320 master:9 - devtmpfs devtmpfs rw,seclabel,size=4107840k,nr_inodes=64185,mode=755
505ca8
719 703 0:6 /loop9 /dev/loop9 rw,nosuid shared:321 master:9 - devtmpfs devtmpfs rw,seclabel,size=4107840k,nr_inodes=64185,mode=755
505ca8
720 697 0:44 / /run rw,nosuid,nodev shared:305 - tmpfs tmpfs rw,seclabel,mode=755
505ca8
721 720 0:25 /systemd/nspawn/propagate/9cc8a155d0244558b273f773d2b92142 /run/systemd/nspawn/incoming ro master:12 - tmpfs tmpfs rw,seclabel,mode=755
505ca8
722 697 0:32 /mock-resolv.dvml91hp /etc/resolv.conf rw,nosuid,nodev shared:322 master:18 - tmpfs tmpfs rw,seclabel
505ca8
725 697 0:47 / /proc rw,nosuid,nodev,noexec,relatime shared:323 - proc proc rw
505ca8
603 725 0:47 /sys /proc/sys ro,nosuid,nodev,noexec,relatime shared:323 - proc proc rw
505ca8
604 725 0:44 /systemd/inaccessible/reg /proc/kallsyms ro,nosuid,nodev,noexec shared:305 - tmpfs tmpfs rw,seclabel,mode=755
505ca8
605 725 0:44 /systemd/inaccessible/reg /proc/kcore ro,nosuid,nodev,noexec shared:305 - tmpfs tmpfs rw,seclabel,mode=755
505ca8
606 725 0:44 /systemd/inaccessible/reg /proc/keys ro,nosuid,nodev,noexec shared:305 - tmpfs tmpfs rw,seclabel,mode=755
505ca8
607 725 0:44 /systemd/inaccessible/reg /proc/sysrq-trigger ro,nosuid,nodev,noexec shared:305 - tmpfs tmpfs rw,seclabel,mode=755
505ca8
608 725 0:44 /systemd/inaccessible/reg /proc/timer_list ro,nosuid,nodev,noexec shared:305 - tmpfs tmpfs rw,seclabel,mode=755
505ca8
609 725 0:47 /bus /proc/bus ro,nosuid,nodev,noexec,relatime shared:323 - proc proc rw
505ca8
610 725 0:47 /fs /proc/fs ro,nosuid,nodev,noexec,relatime shared:323 - proc proc rw
505ca8
611 725 0:47 /irq /proc/irq ro,nosuid,nodev,noexec,relatime shared:323 - proc proc rw
505ca8
612 725 0:47 /scsi /proc/scsi ro,nosuid,nodev,noexec,relatime shared:323 - proc proc rw
505ca8
613 703 0:46 / /dev/mqueue rw,nosuid,nodev,noexec,relatime shared:324 - mqueue mqueue rw,seclabel
505ca8
614 701 0:26 / /sys/fs/cgroup rw,nosuid,nodev,noexec,relatime shared:325 - cgroup2 cgroup rw,seclabel,nsdelegate
505ca8
615 603 0:44 /.#proc-sys-kernel-random-boot-id4fbdce67af46d1c2//deleted /proc/sys/kernel/random/boot_id ro,nosuid,nodev,noexec shared:305 - tmpfs tmpfs rw,seclabel,mode=755
505ca8
616 725 0:44 /.#proc-sys-kernel-random-boot-id4fbdce67af46d1c2//deleted /proc/sys/kernel/random/boot_id rw,nosuid,nodev shared:305 - tmpfs tmpfs rw,seclabel,mode=755
505ca8
617 725 0:44 /.#proc-kmsg5b7a8bcfe6717139//deleted /proc/kmsg rw,nosuid,nodev shared:305 - tmpfs tmpfs rw,seclabel,mode=755
505ca8
505ca8
The test process does
505ca8
name_to_handle_at("/proc/filesystems") which returns -EOPNOTSUPP, and then
505ca8
openat(AT_FDCWD, "/proc/filesystems") which returns 4, and then
505ca8
read(open("/proc/self/fdinfo/4", ...)) which gives
505ca8
"pos:\t0\nflags:\t012100000\nmnt_id:\t725\n"
505ca8
505ca8
and the "725" is clearly inconsistent with "700" in /proc/self/mountinfo.
505ca8
505ca8
We could either drop the fallback path (and fail name_to_handle_at() is not
505ca8
avaliable) or ignore the error in the test. Not sure what is better. I think
505ca8
this issue only occurs sometimes and with older kernels, so probably continuing
505ca8
with the current flaky implementation is better than ripping out the fallback.
505ca8
505ca8
Another strace:
505ca8
writev(2</dev/pts/0>, [{iov_base="mnt ids of /proc/sys is 603", iov_len=27}, {iov_base="\n", iov_len=1}], 2mnt ids of /proc/sys is 603
505ca8
) = 28
505ca8
name_to_handle_at(AT_FDCWD, "/", {handle_bytes=128 => 12, handle_type=129, f_handle=0x52748401000000008b93e20d}, [697], 0) = 0
505ca8
writev(2</dev/pts/0>, [{iov_base="mnt ids of / is 697", iov_len=19}, {iov_base="\n", iov_len=1}], 2mnt ids of / is 697
505ca8
) = 20
505ca8
name_to_handle_at(AT_FDCWD, "/proc/kcore", {handle_bytes=128 => 12, handle_type=1, f_handle=0x92ddcfcd2e802d0100000000}, [605], 0) = 0
505ca8
writev(2</dev/pts/0>, [{iov_base="mnt ids of /proc/kcore is 605", iov_len=29}, {iov_base="\n", iov_len=1}], 2mnt ids of /proc/kcore is 605
505ca8
) = 30
505ca8
name_to_handle_at(AT_FDCWD, "/dev", {handle_bytes=128 => 12, handle_type=1, f_handle=0x8ae269160c802d0100000000}, [703], 0) = 0
505ca8
writev(2</dev/pts/0>, [{iov_base="mnt ids of /dev is 703", iov_len=22}, {iov_base="\n", iov_len=1}], 2mnt ids of /dev is 703
505ca8
) = 23
505ca8
name_to_handle_at(AT_FDCWD, "/proc/filesystems", {handle_bytes=128}, 0x7fffe36ddb84, 0) = -1 EOPNOTSUPP (Operation not supported)
505ca8
openat(AT_FDCWD, "/proc/filesystems", O_RDONLY|O_NOFOLLOW|O_CLOEXEC|O_PATH) = 4</proc/filesystems>
505ca8
openat(AT_FDCWD, "/proc/self/fdinfo/4", O_RDONLY|O_CLOEXEC) = 5</proc/20/fdinfo/4>
505ca8
fstat(5</proc/20/fdinfo/4>, {st_mode=S_IFREG|0400, st_size=0, ...}) = 0
505ca8
fstat(5</proc/20/fdinfo/4>, {st_mode=S_IFREG|0400, st_size=0, ...}) = 0
505ca8
read(5</proc/20/fdinfo/4>, "pos:\t0\nflags:\t012100000\nmnt_id:\t725\n", 2048) = 36
505ca8
read(5</proc/20/fdinfo/4>, "", 1024)    = 0
505ca8
close(5</proc/20/fdinfo/4>)             = 0
505ca8
close(4</proc/filesystems>)             = 0
505ca8
writev(2</dev/pts/0>, [{iov_base="mnt ids of /proc/filesystems are 700, 725", iov_len=41}, {iov_base="\n", iov_len=1}], 2mnt ids of /proc/filesystems are 700, 725
505ca8
) = 42
505ca8
writev(2</dev/pts/0>, [{iov_base="the other path for mnt id 725 is /proc", iov_len=38}, {iov_base="\n", iov_len=1}], 2the other path for mnt id 725 is /proc
505ca8
) = 39
505ca8
writev(2</dev/pts/0>, [{iov_base="Assertion 'path_equal(p, t)' failed at src/test/test-mountpoint-util.c:94, function test_mnt_id(). Aborting.", iov_len=108}, {iov_base="\n", iov_len=1}], 2Assertion 'path_equal(p, t)' failed at src/test/test-mountpoint-util.c:94, function test_mnt_id(). Aborting.
505ca8
) = 109
505ca8
rt_sigprocmask(SIG_UNBLOCK, [ABRT], NULL, 8) = 0
505ca8
rt_sigprocmask(SIG_BLOCK, ~[RTMIN RT_1], [], 8) = 0
505ca8
getpid()                                = 20
505ca8
gettid()                                = 20
505ca8
tgkill(20, 20, SIGABRT)                 = 0
505ca8
rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
505ca8
--- SIGABRT {si_signo=SIGABRT, si_code=SI_TKILL, si_pid=20, si_uid=0} ---
505ca8
+++ killed by SIGABRT (core dumped) +++
505ca8
---
505ca8
 src/test/test-mountpoint-util.c | 8 ++++++--
505ca8
 1 file changed, 6 insertions(+), 2 deletions(-)
505ca8
505ca8
diff --git a/src/test/test-mountpoint-util.c b/src/test/test-mountpoint-util.c
42949c
index 30b00ae4d8b7..ffe5144b04ae 100644
505ca8
--- a/src/test/test-mountpoint-util.c
505ca8
+++ b/src/test/test-mountpoint-util.c
505ca8
@@ -89,8 +89,12 @@ static void test_mnt_id(void) {
505ca8
                 /* The ids don't match? If so, then there are two mounts on the same path, let's check if
505ca8
                  * that's really the case */
505ca8
                 char *t = hashmap_get(h, INT_TO_PTR(mnt_id2));
505ca8
-                log_debug("the other path for mnt id %i is %s\n", mnt_id2, t);
505ca8
-                assert_se(path_equal(p, t));
505ca8
+                log_debug("Path for mnt id %i from /proc/self/mountinfo is %s\n", mnt_id2, t);
505ca8
+
505ca8
+                if (!path_equal(p, t))
505ca8
+                        /* Apparent kernel bug in /proc/self/fdinfo */
505ca8
+                        log_warning("Bad mount id given for %s: %d, should be %d",
505ca8
+                                    p, mnt_id2, mnt_id);
505ca8
         }
505ca8
 }
505ca8