linux/fs
Chuck Lever 80c30e8de4 NLM: Fix "kernel BUG at fs/lockd/host.c:417!" or ".../host.c:283!"
Nick Bowler <nbowler@elliptictech.com> reports:

> We were just having some NFS server troubles, and my client machine
> running 2.6.38-rc1+ (specifically, commit 2b1caf6ed7) crashed
> hard (syslog output appended to this mail).
>
> I'm not sure what the exact timeline was or how to reproduce this,
> but the server was rebooted during all this.  Since I've never seen
> this happen before, it is possibly a regression from previous kernel
> releases.  However, I recently updated my nfs-utils (on the client) to
> version 1.2.3, so that might be related as well.

  [ BUG output redacted ]

When done searching, the for_each_host loop in next_host_state() falls
through and returns the final host on the host chain without bumping
it's reference count.

Since the host's ref count is only one at that point, releasing the
host in nlm_host_rebooted() attempts to destroy the host prematurely,
and therefore hits a BUG().

Likely, the original intent of the for_each_host behavior in
next_host_state() was to handle the case when the host chain is empty.
Searching the chain and finding no suitable host to return needs to be
handled as well.

Defensively restructure next_host_state() always to return NULL when
the loop falls through.

Introduced by commit b10e30f6 "lockd: reorganize nlm_host_rebooted".

Cc: J. Bruce Fields <bfields@fieldses.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-01-25 15:24:47 -05:00
..
9p switch 9p 2011-01-12 20:03:43 -05:00
adfs switch adfs 2011-01-12 20:02:45 -05:00
affs switch affs 2011-01-12 20:03:42 -05:00
afs Unexport do_add_mount() and add in follow_automount(), not ->d_automount() 2011-01-15 20:07:48 -05:00
autofs4 autofs4: clean ->d_release() and autofs4_free_ino() up 2011-01-18 01:21:29 -05:00
befs befs: don't pass huge structs by value 2011-01-13 08:03:15 -08:00
bfs fs: icache RCU free inodes 2011-01-07 17:50:26 +11:00
btrfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable 2011-01-17 14:43:43 -08:00
cachefiles
ceph Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client 2011-01-13 10:25:24 -08:00
cifs Merge git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6 2011-01-17 11:17:51 -08:00
coda Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2011-01-13 10:27:28 -08:00
configfs configfs: change depends -> select SYSFS 2011-01-16 21:22:29 +00:00
cramfs cramfs: generate unique inode number for better inode cache usage 2011-01-13 08:03:23 -08:00
debugfs
devpts
dlm dlm: Make DLM depend on CONFIGFS_FS 2011-01-16 21:22:37 +00:00
ecryptfs ecryptfs: remove unnecessary decrypt when extending a file 2011-01-17 13:01:25 -06:00
efs fs: icache RCU free inodes 2011-01-07 17:50:26 +11:00
exofs fs: icache RCU free inodes 2011-01-07 17:50:26 +11:00
exportfs fs: dcache per-inode inode alias locking 2011-01-07 17:50:31 +11:00
ext2 Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 2011-01-11 14:37:31 -08:00
ext3 Merge branch 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-block 2011-01-13 10:45:01 -08:00
ext4 fallocate should be a file operation 2011-01-17 02:25:31 -05:00
fat switch fat to ->s_d_op, close exportfs races there 2011-01-12 20:02:43 -05:00
freevxfs fs: icache RCU free inodes 2011-01-07 17:50:26 +11:00
fscache FS-Cache: Fix operation handling 2011-01-14 09:23:36 -08:00
fuse switch fuse 2011-01-12 20:02:44 -05:00
gfs2 fallocate should be a file operation 2011-01-17 02:25:31 -05:00
hfs switch hfs 2011-01-12 20:02:45 -05:00
hfsplus switch hfsplus 2011-01-12 20:02:45 -05:00
hostfs switch hostfs 2011-01-12 20:03:42 -05:00
hpfs hpfs_setattr error case avoids unlock_kernel 2011-01-17 05:11:37 -05:00
hppfs fs: icache RCU free inodes 2011-01-07 17:50:26 +11:00
hugetlbfs fs: icache RCU free inodes 2011-01-07 17:50:26 +11:00
isofs fix isofs d_op handling 2011-01-12 20:02:43 -05:00
jbd fix comment typos concerning "consistent" 2010-12-10 16:04:28 +01:00
jbd2 Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2011-01-13 10:05:56 -08:00
jffs2 Merge git://git.infradead.org/mtd-2.6 2011-01-17 11:15:30 -08:00
jfs Merge branch 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-block 2011-01-13 10:45:01 -08:00
lockd NLM: Fix "kernel BUG at fs/lockd/host.c:417!" or ".../host.c:283!" 2011-01-25 15:24:47 -05:00
logfs Merge branch 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-block 2011-01-13 10:45:01 -08:00
minix minixfs: kill dead code 2011-01-12 20:02:44 -05:00
ncpfs move internal-only parts of ncpfs headers to fs/ncpfs 2011-01-12 20:03:43 -05:00
nfs NFS: Prevent memory allocation failure in nfsacl_encode() 2011-01-25 15:24:47 -05:00
nfs_common NFS: Prevent memory allocation failure in nfsacl_encode() 2011-01-25 15:24:47 -05:00
nfsd Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2011-01-16 11:31:50 -08:00
nilfs2 Merge branch 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-block 2011-01-13 10:45:01 -08:00
nls
notify Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2011-01-13 10:05:56 -08:00
ntfs NTFS: writev() fix and maintenance/contact details update 2011-01-12 08:35:53 -08:00
ocfs2 fallocate should be a file operation 2011-01-17 02:25:31 -05:00
omfs
openpromfs fs: icache RCU free inodes 2011-01-07 17:50:26 +11:00
partitions Merge branch 'for-2.6.38/event-handling' into for-2.6.38/core 2011-01-13 14:47:54 +01:00
proc thp: remove PG_buddy 2011-01-13 17:32:43 -08:00
qnx4 fs: icache RCU free inodes 2011-01-07 17:50:26 +11:00
quota quota: Use %pV and __attribute__((format (printf in __quota_error and fix fallout 2011-01-10 19:04:05 +01:00
ramfs
reiserfs Merge branch 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-block 2011-01-13 10:45:01 -08:00
romfs fs: icache RCU free inodes 2011-01-07 17:50:26 +11:00
squashfs Squashfs: simplify CONFIG_SQUASHFS_LZO handling 2011-01-13 21:38:46 +00:00
sysfs Merge branch 'driver-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6 2011-01-10 16:10:33 -08:00
sysv switch sysv 2011-01-12 20:02:44 -05:00
ubifs fs: icache RCU free inodes 2011-01-07 17:50:26 +11:00
udf Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-udf-2.6 2011-01-11 14:45:52 -08:00
ufs fs: icache RCU free inodes 2011-01-07 17:50:26 +11:00
xfs xfs: Do not name variables "panic" 2011-01-17 12:39:07 -08:00
aio.c aio: check return value of create_workqueue() 2011-01-17 05:12:44 -05:00
anon_inodes.c sanitize vfsmount refcounting changes 2011-01-16 13:47:07 -05:00
attr.c
bad_inode.c fs: provide rcu-walk aware permission i_ops 2011-01-07 17:50:29 +11:00
binfmt_aout.c
binfmt_elf_fdpic.c
binfmt_elf.c binfmt_elf: cleanups 2011-01-13 08:03:12 -08:00
binfmt_em86.c
binfmt_flat.c
binfmt_misc.c
binfmt_script.c
binfmt_som.c
bio-integrity.c bio-integrity: mark kintegrityd_wq highpri and CPU intensive 2011-01-03 15:01:48 +01:00
bio.c
block_dev.c block: restore multiple bd_link_disk_holder() support 2011-01-14 18:44:22 +01:00
buffer.c fs: Use this_cpu_inc_return in buffer.c 2010-12-17 15:18:05 +01:00
char_dev.c Merge branch 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-block 2011-01-13 10:45:01 -08:00
compat_binfmt_elf.c
compat_ioctl.c Merge branch 'tty-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty-2.6 2011-01-07 14:39:20 -08:00
compat.c compat: copy missing fields in compat_statfs64 to user 2011-01-17 04:54:38 -05:00
dcache.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2011-01-16 11:31:50 -08:00
dcookies.c
direct-io.c
drop_caches.c
eventfd.c
eventpoll.c epoll: convert max_user_watches to long 2011-01-13 08:03:12 -08:00
exec.c install_special_mapping skips security_file_mmap check. 2010-12-15 12:30:36 -08:00
fcntl.c
fifo.c
file_table.c fs: Remove unlikely() from fget_light() 2011-01-17 03:26:27 -05:00
file.c
filesystems.c fs: rcu-walk for path lookup 2011-01-07 17:50:27 +11:00
fs_struct.c sanitize vfsmount refcounting changes 2011-01-16 13:47:07 -05:00
fs-writeback.c fs/fs-writeback.c: fix sync_inodes_sb() return value kernel-doc 2011-01-13 17:32:48 -08:00
generic_acl.c fs: provide simple rcu-walk generic_check_acl implementation 2011-01-07 17:50:29 +11:00
inode.c fs: avoid inode RCU freeing for pseudo fs 2011-01-07 17:50:26 +11:00
internal.h tidy up around finish_automount() 2011-01-17 01:47:59 -05:00
ioctl.c fs: fix address space warnings in ioctl_fiemap() 2011-01-17 08:21:42 -05:00
ioprio.c
Kconfig fs: FS_POSIX_ACL does not depend on BLOCK 2011-01-17 03:30:37 -05:00
Kconfig.binfmt
libfs.c pass default dentry_operations to mount_pseudo() 2011-01-12 20:03:43 -05:00
locks.c Merge branch 'for-2.6.38' of git://linux-nfs.org/~bfields/linux 2011-01-14 13:17:26 -08:00
Makefile
mbcache.c ext2: Resolve 'dereferencing pointer to incomplete type' when enabling EXT2_XATTR_DEBUG 2011-01-10 19:04:08 +01:00
mpage.c fs/mpage.c: consolidate code 2011-01-13 17:32:32 -08:00
namei.c vfs - fix dentry ref count in do_lookup() 2011-01-18 01:21:26 -05:00
namespace.c tidy up around finish_automount() 2011-01-17 01:47:59 -05:00
nfsctl.c
no-block.c
open.c fallocate should be a file operation 2011-01-17 02:25:31 -05:00
pipe.c sanitize vfsmount refcounting changes 2011-01-16 13:47:07 -05:00
pnode.c fs: scale mntget/mntput 2011-01-07 17:50:33 +11:00
pnode.h
posix_acl.c NFS: Prevent memory allocation failure in nfsacl_encode() 2011-01-25 15:24:47 -05:00
read_write.c fix signedness mess in rw_verify_area() on 64bit architectures 2011-01-12 20:06:58 -05:00
read_write.h
readdir.c
select.c fs/select.c: fix information leak to userspace 2011-01-13 08:03:12 -08:00
seq_file.c
signalfd.c
splice.c Merge branch 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-block 2011-01-13 10:45:01 -08:00
stack.c
stat.c Add an AT_NO_AUTOMOUNT flag to suppress terminal automount 2011-01-15 20:07:33 -05:00
statfs.c
super.c sanitize vfsmount refcounting changes 2011-01-16 13:47:07 -05:00
sync.c
timerfd.c
utimes.c
xattr_acl.c
xattr.c