Roman Pen a8f324a46f debugfs: fix inode i_nlink references for automount dentry ... Directory inodes should start off with i_nlink == 2 (one extra ref for "." entry). debugfs_create_automount() increases neither the i_nlink reference for current inode nor for parent inode. On attempt to remove the automount dentry, kernel complains: [ 86.288070] WARNING: CPU: 1 PID: 3616 at fs/inode.c:273 drop_nlink+0x3e/0x50() [ 86.288461] Modules linked in: debugfs_example2(O-) [ 86.288745] CPU: 1 PID: 3616 Comm: rmmod Tainted: G O 4.4.0-rc3-next-20151207+ #135 [ 86.289197] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.8.2-20150617_082717-anatol 04/01/2014 [ 86.289696] ffffffff81be05c9 ffff8800b9e6fda0 ffffffff81352e2c 0000000000000000 [ 86.290110] ffff8800b9e6fdd8 ffffffff81065142 ffff8801399175e8 ffff8800bb78b240 [ 86.290507] ffff8801399175e8 ffff8800b73d7898 ffff8800b73d7840 ffff8800b9e6fde8 [ 86.290933] Call Trace: [ 86.291080] [<ffffffff81352e2c>] dump_stack+0x4e/0x82 [ 86.291340] [<ffffffff81065142>] warn_slowpath_common+0x82/0xc0 [ 86.291640] [<ffffffff8106523a>] warn_slowpath_null+0x1a/0x20 [ 86.291932] [<ffffffff811ae62e>] drop_nlink+0x3e/0x50 [ 86.292208] [<ffffffff811ba35b>] simple_unlink+0x4b/0x60 [ 86.292481] [<ffffffff811ba3a7>] simple_rmdir+0x37/0x50 [ 86.292748] [<ffffffff812d9808>] __debugfs_remove.part.16+0xa8/0xd0 [ 86.293082] [<ffffffff812d9a0b>] debugfs_remove_recursive+0xdb/0x1c0 [ 86.293406] [<ffffffffa00004dd>] cleanup_module+0x2d/0x3b [debugfs_example2] [ 86.293762] [<ffffffff810d959b>] SyS_delete_module+0x16b/0x220 [ 86.294077] [<ffffffff818ef857>] entry_SYSCALL_64_fastpath+0x12/0x6a [ 86.294405] ---[ end trace c9fc53353fe14a36 ]--- [ 86.294639] ------------[ cut here ]------------ To reproduce the issue it is enough to invoke these lines: autom = debugfs_create_automount("automount", NULL, vfsmount_cb, data); BUG_ON(IS_ERR_OR_NULL(autom)); debugfs_remove(autom); The issue is fixed by increasing inode i_nlink references for current and parent inodes. Signed-off-by: Roman Pen <r.peniaev@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2016-03-29 10:11:44 -07:00
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9p	…
adfs	…
affs	…
afs	…
autofs4	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2016-03-19 18:52:29 -07:00
befs	…
bfs	…
btrfs	Merge branch 'for-linus-4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs	2016-03-21 18:12:42 -07:00
cachefiles	…
ceph	ceph: use kmem_cache_zalloc	2016-03-25 18:51:56 +01:00
cifs	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2016-03-19 18:52:29 -07:00
coda	…
configfs	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2016-03-19 18:52:29 -07:00
cramfs	…
crypto	f2fs/crypto: fix xts_tweak initialization	2016-03-26 10:13:05 -07:00
debugfs	debugfs: fix inode i_nlink references for automount dentry	2016-03-29 10:11:44 -07:00
devpts	…
dlm	…
ecryptfs	Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6	2016-03-23 06:12:39 -07:00
efivarfs	…
efs	…
exofs	…
exportfs	…
ext2	…
ext4	ext4: in ext4_dir_llseek, check syscall bitness directly	2016-03-22 15:36:02 -07:00
f2fs	…
fat	fat: add config option to set UTF-8 mount option by default	2016-03-22 15:36:02 -07:00
freevxfs	…
fscache	…
fuse	…
gfs2	…
hfs	…
hfsplus	…
hostfs	…
hpfs	…
hugetlbfs	…
isofs	…
jbd2	…
jffs2	MTD updates for v4.6	2016-03-24 19:57:15 -07:00
jfs	…
kernfs	Merge branch 'for-4.6-ns' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup	2016-03-21 10:05:13 -07:00
lockd	…
logfs	…
minix	…
ncpfs	…
nfs	Various bugfixes, a RDMA update from Chuck Lever, and support for a new	2016-03-24 19:50:32 -07:00
nfs_common	…
nfsd	Various bugfixes, a RDMA update from Chuck Lever, and support for a new	2016-03-24 19:50:32 -07:00
nilfs2	…
nls	…
notify	…
ntfs	…
ocfs2	ocfs2: extend enough credits for freeing one truncate record while replaying truncate records	2016-03-25 16:37:42 -07:00
omfs	…
openpromfs	…
orangefs	orangefs: fix orangefs_superblock locking	2016-03-26 07:22:00 -04:00
overlayfs	ovl: cleanup unused var in rename2	2016-03-21 17:31:46 +01:00
proc	Merge branch 'for-4.6-ns' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup	2016-03-21 10:05:13 -07:00
pstore	…
qnx4	…
qnx6	…
quota	Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs	2016-03-21 12:22:37 -07:00
ramfs	…
reiserfs	…
romfs	…
squashfs	…
sysfs	…
sysv	…
tracefs	…
ubifs	ubifs: Remove unused header	2016-03-20 21:37:46 +01:00
udf	…
ufs	…
xfs	Various bugfixes, a RDMA update from Chuck Lever, and support for a new	2016-03-24 19:50:32 -07:00
Kconfig	Merge tag 'ofs-pull-tag-1' of git://git.kernel.org/pub/scm/linux/kernel/git/hubcap/linux	2016-03-26 12:59:04 -07:00
Kconfig.binfmt	…
Makefile	Merge tag 'ofs-pull-tag-1' of git://git.kernel.org/pub/scm/linux/kernel/git/hubcap/linux	2016-03-26 12:59:04 -07:00
aio.c	…
anon_inodes.c	…
attr.c	…
bad_inode.c	…
binfmt_aout.c	…
binfmt_elf.c	…
binfmt_elf_fdpic.c	…
binfmt_em86.c	…
binfmt_flat.c	…
binfmt_misc.c	…
binfmt_script.c	…
block_dev.c	…
buffer.c	…
char_dev.c	chrdev: emit a warning when we go below dynamic major range	2016-03-29 10:11:44 -07:00
compat.c	…
compat_binfmt_elf.c	…
compat_ioctl.c	…
coredump.c	fs/coredump: prevent fsuid=0 dumps into user-controlled directories	2016-03-22 15:36:02 -07:00
dax.c	xfs: Changes for 4.6-rc1	2016-03-21 11:53:05 -07:00
dcache.c	…
dcookies.c	…
direct-io.c	xfs: Changes for 4.6-rc1	2016-03-21 11:53:05 -07:00
drop_caches.c	…
eventfd.c	eventfd: document lockless access in eventfd_poll	2016-03-22 15:36:02 -07:00
eventpoll.c	…
exec.c	Merge branch 'mm-pkeys-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2016-03-20 19:08:56 -07:00
fcntl.c	…
fhandle.c	fs/coredump: prevent fsuid=0 dumps into user-controlled directories	2016-03-22 15:36:02 -07:00
file.c	…
file_table.c	…
filesystems.c	…
fs-writeback.c	writeback, cgroup: fix use of the wrong bdi_writeback which mismatches the inode	2016-03-20 09:44:20 -06:00
fs_pin.c	…
fs_struct.c	…
inode.c	…
internal.h	…
ioctl.c	…
libfs.c	…
locks.c	…
mbcache.c	…
mount.h	…
mpage.c	…
namei.c	…
namespace.c	…
no-block.c	…
nsfs.c	…
open.c	fs/coredump: prevent fsuid=0 dumps into user-controlled directories	2016-03-22 15:36:02 -07:00
pipe.c	…
pnode.c	…
pnode.h	…
posix_acl.c	…
proc_namespace.c	…
read_write.c	…
readdir.c	…
select.c	…
seq_file.c	…
signalfd.c	…
splice.c	…
stack.c	…
stat.c	…
statfs.c	…
super.c	…
sync.c	…
timerfd.c	…
userfaultfd.c	…
utimes.c	…
xattr.c	…