linux/fs
David Howells 341f741f04 afs: Refcount the afs_call struct
A static checker warning occurs in the AFS filesystem:

	fs/afs/cmservice.c:155 SRXAFSCB_CallBack()
	error: dereferencing freed memory 'call'

due to the reply being sent before we access the server it points to.  The
act of sending the reply causes the call to be freed if an error occurs
(but not if it doesn't).

On top of this, the lifetime handling of afs_call structs is fragile
because they get passed around through workqueues without any sort of
refcounting.

Deal with the issues by:

 (1) Fix the maybe/maybe not nature of the reply sending functions with
     regards to whether they release the call struct.

 (2) Refcount the afs_call struct and sort out places that need to get/put
     references.

 (3) Pass a ref through the work queue and release (or pass on) that ref in
     the work function.  Care has to be taken because a work queue may
     already own a ref to the call.

 (4) Do the cleaning up in the put function only.

 (5) Simplify module cleanup by always incrementing afs_outstanding_calls
     whenever a call is allocated.

 (6) Set the backlog to 0 with kernel_listen() at the beginning of the
     process of closing the socket to prevent new incoming calls from
     occurring and to remove the contribution of preallocated calls from
     afs_outstanding_calls before we wait on it.

A tracepoint is also added to monitor the afs_call refcount and lifetime.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Fixes: 08e0e7c82e: "[AF_RXRPC]: Make the in-kernel AFS filesystem use AF_RXRPC."
2017-01-09 11:10:02 +00:00
..
9p Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
adfs
affs vfs: remove ".readlink = generic_readlink" assignments 2016-12-09 16:45:04 +01:00
afs afs: Refcount the afs_call struct 2017-01-09 11:10:02 +00:00
autofs4 Merge uncontroversial parts of branch 'readlink' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs 2016-12-17 19:16:12 -08:00
befs befs: add NFS export support 2016-12-22 11:25:24 +00:00
bfs Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
btrfs Merge uncontroversial parts of branch 'readlink' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs 2016-12-17 19:16:12 -08:00
cachefiles
ceph Merge uncontroversial parts of branch 'readlink' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs 2016-12-17 19:16:12 -08:00
cifs Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
coda vfs: remove ".readlink = generic_readlink" assignments 2016-12-09 16:45:04 +01:00
configfs Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
cramfs
crypto fscrypt: fix renaming and linking special files 2016-12-31 00:47:05 -05:00
debugfs
devpts
dlm ktime: Get rid of ktime_equal() 2016-12-25 17:21:23 +01:00
ecryptfs vfs: remove ".readlink = generic_readlink" assignments 2016-12-09 16:45:04 +01:00
efivarfs
efs Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
exofs exofs: don't mess with simple_write_{begin,end} 2016-12-10 14:25:19 -05:00
exportfs
ext2 ext2: Return BH_New buffers for zeroed blocks 2016-12-26 20:29:24 -08:00
ext4 ext4: Simplify DAX fault path 2016-12-26 20:29:25 -08:00
f2fs Merge uncontroversial parts of branch 'readlink' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs 2016-12-17 19:16:12 -08:00
fat
freevxfs
fscache
fuse Merge uncontroversial parts of branch 'readlink' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs 2016-12-17 19:16:12 -08:00
gfs2 ktime: Cleanup ktime_set() usage 2016-12-25 17:21:22 +01:00
hfs Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
hfsplus Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
hostfs vfs: remove ".readlink = generic_readlink" assignments 2016-12-09 16:45:04 +01:00
hpfs
hugetlbfs Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
isofs Merge branch 'for-4.10/block' of git://git.kernel.dk/linux-block 2016-12-13 10:19:16 -08:00
jbd2 Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
jffs2 vfs: remove ".readlink = generic_readlink" assignments 2016-12-09 16:45:04 +01:00
jfs Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
kernfs Merge uncontroversial parts of branch 'readlink' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs 2016-12-17 19:16:12 -08:00
lockd
minix vfs: remove ".readlink = generic_readlink" assignments 2016-12-09 16:45:04 +01:00
ncpfs Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
nfs ktime: Get rid of ktime_equal() 2016-12-25 17:21:23 +01:00
nfs_common
nfsd Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
nilfs2 Merge uncontroversial parts of branch 'readlink' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs 2016-12-17 19:16:12 -08:00
nls
notify Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs 2016-12-19 08:23:53 -08:00
ntfs Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
ocfs2 ktime: Get rid of the union 2016-12-25 17:21:22 +01:00
omfs
openpromfs Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
orangefs Merge uncontroversial parts of branch 'readlink' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs 2016-12-17 19:16:12 -08:00
overlayfs Merge uncontroversial parts of branch 'readlink' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs 2016-12-17 19:16:12 -08:00
proc Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
pstore Improvements and fixes to pstore subsystem: 2016-12-13 09:16:11 -08:00
qnx4
qnx6
quota Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs 2016-12-19 08:23:53 -08:00
ramfs Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
reiserfs Merge uncontroversial parts of branch 'readlink' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs 2016-12-17 19:16:12 -08:00
romfs
squashfs Merge uncontroversial parts of branch 'readlink' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs 2016-12-17 19:16:12 -08:00
sysfs
sysv vfs: remove ".readlink = generic_readlink" assignments 2016-12-09 16:45:04 +01:00
tracefs
ubifs Merge uncontroversial parts of branch 'readlink' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs 2016-12-17 19:16:12 -08:00
udf
ufs Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
xfs xfs: fix max_retries _show and _store functions 2017-01-03 20:34:17 -08:00
aio.c ktime: Get rid of the union 2016-12-25 17:21:22 +01:00
anon_inodes.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
attr.c
bad_inode.c bad_inode: add missing i_op initializers 2016-12-09 11:57:43 +01:00
binfmt_aout.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
binfmt_elf_fdpic.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
binfmt_elf.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
binfmt_em86.c
binfmt_flat.c
binfmt_misc.c
binfmt_script.c
block_dev.c Merge branch 'for-linus' of git://git.kernel.dk/linux-block 2017-01-04 09:03:37 -08:00
buffer.c clean_bdev_aliases: Prevent cleaning blocks that are not in block range 2017-01-02 09:35:14 -07:00
char_dev.c
compat_binfmt_elf.c
compat_ioctl.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
compat.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
coredump.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
dax.c dax: Call ->iomap_begin without entry lock during dax fault 2016-12-26 20:29:25 -08:00
dcache.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
dcookies.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
direct-io.c xfs: updates for 4.10-rc1 2016-12-14 21:35:31 -08:00
drop_caches.c
eventfd.c
eventpoll.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
exec.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
fcntl.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
fhandle.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
file_table.c constify alloc_file() 2016-12-05 19:01:16 -05:00
file.c
filesystems.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
fs_pin.c
fs_struct.c
fs-writeback.c fs/fs-writeback.c: remove redundant if check 2016-12-12 18:55:08 -08:00
inode.c
internal.h Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2016-12-17 18:44:00 -08:00
ioctl.c vfs: call vfs_clone_file_range() under freeze protection 2016-12-16 11:02:54 +01:00
iomap.c xfs: updates for 4.10-rc1 2016-12-14 21:35:31 -08:00
Kconfig Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2016-12-16 10:24:44 -08:00
Kconfig.binfmt
libfs.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
locks.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
Makefile logfs: remove from tree 2016-12-14 23:48:11 -05:00
mbcache.c
mount.h
mpage.c
namei.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
namespace.c Merge branch 'work.namespace' into for-linus 2016-12-22 23:04:31 -05:00
no-block.c
nsfs.c
open.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
pipe.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
pnode.c reorganize do_make_slave() 2016-12-16 16:30:49 -05:00
pnode.h
posix_acl.c
proc_namespace.c
read_write.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
readdir.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
select.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
seq_file.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
signalfd.c
splice.c splice: reinstate SIGPIPE/EPIPE handling 2016-12-21 10:59:34 -08:00
stack.c
stat.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
statfs.c vfs: misc struct path constification 2016-12-05 19:03:49 -05:00
super.c
sync.c
timerfd.c ktime: Cleanup ktime_set() usage 2016-12-25 17:21:22 +01:00
userfaultfd.c mm: join struct fault_env and vm_fault 2016-12-14 16:04:09 -08:00
utimes.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
xattr.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00