From: Kevin Hao <kexin.hao@windriver.com>
To: <util-linux@vger.kernel.org>
Subject: [PATCH] libmount: Keep the mnt_tab info for the existent dest in mnt_copy_fs()
Date: Mon, 19 Aug 2019 16:30:22 +0800 [thread overview]
Message-ID: <20190819083022.12289-1-kexin.hao@windriver.com> (raw)
The "umount -f -a -r" get stuck in a endless loop when run with a
mountinfo like below:
15 0 179:2 / / ro,relatime - ext4 /dev/root ro
16 15 0:6 / /dev rw,relatime - devtmpfs devtmpfs rw,size=242896k,nr_inodes=60724,mode=755
17 15 0:4 / /proc rw,relatime - proc proc rw
18 15 0:15 / /mnt/.psplash rw,relatime - tmpfs tmpfs rw,size=40k
19 15 0:16 / /sys rw,relatime - sysfs sysfs rw
20 19 0:7 / /sys/kernel/debug rw,relatime - debugfs debugfs rw
21 15 0:17 / /run rw,nosuid,nodev - tmpfs tmpfs rw,mode=755
22 15 0:18 / /var/volatile rw,relatime - tmpfs tmpfs rw
23 15 179:1 / /boot rw,relatime - vfat /dev/mmcblk0p1 rw,fmask=0022,dmask=0022,codepage=437,iocharset=iso8859-1,shortname=mixed,errors=remount-ro
24 16 0:19 / /dev/pts rw,relatime - devpts devpts rw,gid=5,mode=620,ptmxmode=000
25 18 0:20 / /mnt/.psplash rw,relatime - tmpfs tmpfs rw,size=40k
The reason is that the two same mnt entry "/mnt/.psplash" will cause
the dst->tab set to NULL when umount this mnt entry the second time.
This will trigger an endless loop in mnt_reset_table() because that
mnt entry is linked on the libmnt_table but its .tab is set to NULL.
Signed-off-by: Kevin Hao <kexin.hao@windriver.com>
---
libmount/src/fs.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/libmount/src/fs.c b/libmount/src/fs.c
index eb89bb8a39be..4126ee9dce85 100644
--- a/libmount/src/fs.c
+++ b/libmount/src/fs.c
@@ -188,9 +188,10 @@ struct libmnt_fs *mnt_copy_fs(struct libmnt_fs *dest,
dest = mnt_new_fs();
if (!dest)
return NULL;
+
+ dest->tab = NULL;
}
- dest->tab = NULL;
dest->id = src->id;
dest->parent = src->parent;
dest->devno = src->devno;
--
2.14.4
next reply other threads:[~2019-08-19 8:33 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-19 8:30 Kevin Hao [this message]
2019-08-19 12:59 ` [PATCH] libmount: Keep the mnt_tab info for the existent dest in mnt_copy_fs() Karel Zak
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