https://github.com/torvalds/linux
Revision 1e9c75fb9c47a75a9aec0cd17db5f6dc36b58e00 authored by Benjamin Coddington on 03 October 2018, 14:18:33 UTC, committed by Eric W. Biederman on 12 November 2018, 07:02:34 UTC
Since commit ff17fa561a04 ("d_invalidate(): unhash immediately") immediately unhashes the dentry, we'll never return the mountpoint in lookup_mountpoint(), which can lead to an unbreakable loop in d_invalidate(). I have reports of NFS clients getting into this condition after the server removes an export of an existing mount created through follow_automount(), but I suspect there are various other ways to produce this problem if we hunt down users of d_invalidate(). For example, it is possible to get into this state by using XFS' d_invalidate() call in xfs_vn_unlink(): truncate -s 100m img{1,2} mkfs.xfs -q -n version=ci img1 mkfs.xfs -q -n version=ci img2 mkdir -p /mnt/xfs mount img1 /mnt/xfs mkdir /mnt/xfs/sub1 mount img2 /mnt/xfs/sub1 cat > /mnt/xfs/sub1/foo & umount -l /mnt/xfs/sub1 mount img2 /mnt/xfs/sub1 mount --make-private /mnt/xfs mkdir /mnt/xfs/sub2 mount --move /mnt/xfs/sub1 /mnt/xfs/sub2 rmdir /mnt/xfs/sub1 Fix this by moving the check for an unlinked dentry out of the detach_mounts() path. Fixes: ff17fa561a04 ("d_invalidate(): unhash immediately") Cc: stable@vger.kernel.org Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Benjamin Coddington <bcodding@redhat.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
1 parent 9c8e0a1
Tip revision: 1e9c75fb9c47a75a9aec0cd17db5f6dc36b58e00 authored by Benjamin Coddington on 03 October 2018, 14:18:33 UTC
mnt: fix __detach_mounts infinite loop
mnt: fix __detach_mounts infinite loop
Tip revision: 1e9c75f
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arch | ||
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certs | ||
crypto | ||
drivers | ||
firmware | ||
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include | ||
init | ||
ipc | ||
kernel | ||
lib | ||
mm | ||
net | ||
samples | ||
scripts | ||
security | ||
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tools | ||
usr | ||
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.clang-format | -rw-r--r-- | 12.7 KB |
.cocciconfig | -rw-r--r-- | 59 bytes |
.get_maintainer.ignore | -rw-r--r-- | 31 bytes |
.gitattributes | -rw-r--r-- | 30 bytes |
.gitignore | -rw-r--r-- | 1.5 KB |
.mailmap | -rw-r--r-- | 10.5 KB |
COPYING | -rw-r--r-- | 423 bytes |
CREDITS | -rw-r--r-- | 96.4 KB |
Kbuild | -rw-r--r-- | 2.2 KB |
Kconfig | -rw-r--r-- | 563 bytes |
MAINTAINERS | -rw-r--r-- | 470.2 KB |
Makefile | -rw-r--r-- | 59.7 KB |
README | -rw-r--r-- | 727 bytes |
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