David Howells 9faaff5934 rxrpc: Provide a different lockdep key for call->user_mutex for kernel calls ... Provide a different lockdep key for rxrpc_call::user_mutex when the call is made on a kernel socket, such as by the AFS filesystem. The problem is that lockdep registers a false positive between userspace calling the sendmsg syscall on a user socket where call->user_mutex is held whilst userspace memory is accessed whereas the AFS filesystem may perform operations with mmap_sem held by the caller. In such a case, the following warning is produced. ====================================================== WARNING: possible circular locking dependency detected 4.14.0-fscache+ #243 Tainted: G E ------------------------------------------------------ modpost/16701 is trying to acquire lock: (&vnode->io_lock){+.+.}, at: [<ffffffffa000fc40>] afs_begin_vnode_operation+0x33/0x77 [kafs] but task is already holding lock: (&mm->mmap_sem){++++}, at: [<ffffffff8104376a>] __do_page_fault+0x1ef/0x486 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&mm->mmap_sem){++++}: __might_fault+0x61/0x89 _copy_from_iter_full+0x40/0x1fa rxrpc_send_data+0x8dc/0xff3 rxrpc_do_sendmsg+0x62f/0x6a1 rxrpc_sendmsg+0x166/0x1b7 sock_sendmsg+0x2d/0x39 ___sys_sendmsg+0x1ad/0x22b __sys_sendmsg+0x41/0x62 do_syscall_64+0x89/0x1be return_from_SYSCALL_64+0x0/0x75 -> #2 (&call->user_mutex){+.+.}: __mutex_lock+0x86/0x7d2 rxrpc_new_client_call+0x378/0x80e rxrpc_kernel_begin_call+0xf3/0x154 afs_make_call+0x195/0x454 [kafs] afs_vl_get_capabilities+0x193/0x198 [kafs] afs_vl_lookup_vldb+0x5f/0x151 [kafs] afs_create_volume+0x2e/0x2f4 [kafs] afs_mount+0x56a/0x8d7 [kafs] mount_fs+0x6a/0x109 vfs_kern_mount+0x67/0x135 do_mount+0x90b/0xb57 SyS_mount+0x72/0x98 do_syscall_64+0x89/0x1be return_from_SYSCALL_64+0x0/0x75 -> #1 (k-sk_lock-AF_RXRPC){+.+.}: lock_sock_nested+0x74/0x8a rxrpc_kernel_begin_call+0x8a/0x154 afs_make_call+0x195/0x454 [kafs] afs_fs_get_capabilities+0x17a/0x17f [kafs] afs_probe_fileserver+0xf7/0x2f0 [kafs] afs_select_fileserver+0x83f/0x903 [kafs] afs_fetch_status+0x89/0x11d [kafs] afs_iget+0x16f/0x4f8 [kafs] afs_mount+0x6c6/0x8d7 [kafs] mount_fs+0x6a/0x109 vfs_kern_mount+0x67/0x135 do_mount+0x90b/0xb57 SyS_mount+0x72/0x98 do_syscall_64+0x89/0x1be return_from_SYSCALL_64+0x0/0x75 -> #0 (&vnode->io_lock){+.+.}: lock_acquire+0x174/0x19f __mutex_lock+0x86/0x7d2 afs_begin_vnode_operation+0x33/0x77 [kafs] afs_fetch_data+0x80/0x12a [kafs] afs_readpages+0x314/0x405 [kafs] __do_page_cache_readahead+0x203/0x2ba filemap_fault+0x179/0x54d __do_fault+0x17/0x60 __handle_mm_fault+0x6d7/0x95c handle_mm_fault+0x24e/0x2a3 __do_page_fault+0x301/0x486 do_page_fault+0x236/0x259 page_fault+0x22/0x30 __clear_user+0x3d/0x60 padzero+0x1c/0x2b load_elf_binary+0x785/0xdc7 search_binary_handler+0x81/0x1ff do_execveat_common.isra.14+0x600/0x888 do_execve+0x1f/0x21 SyS_execve+0x28/0x2f do_syscall_64+0x89/0x1be return_from_SYSCALL_64+0x0/0x75 other info that might help us debug this: Chain exists of: &vnode->io_lock --> &call->user_mutex --> &mm->mmap_sem Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&mm->mmap_sem); lock(&call->user_mutex); lock(&mm->mmap_sem); lock(&vnode->io_lock); *** DEADLOCK *** 1 lock held by modpost/16701: #0: (&mm->mmap_sem){++++}, at: [<ffffffff8104376a>] __do_page_fault+0x1ef/0x486 stack backtrace: CPU: 0 PID: 16701 Comm: modpost Tainted: G E 4.14.0-fscache+ #243 Hardware name: ASUS All Series/H97-PLUS, BIOS 2306 10/09/2014 Call Trace: dump_stack+0x67/0x8e print_circular_bug+0x341/0x34f check_prev_add+0x11f/0x5d4 ? add_lock_to_list.isra.12+0x8b/0x8b ? add_lock_to_list.isra.12+0x8b/0x8b ? __lock_acquire+0xf77/0x10b4 __lock_acquire+0xf77/0x10b4 lock_acquire+0x174/0x19f ? afs_begin_vnode_operation+0x33/0x77 [kafs] __mutex_lock+0x86/0x7d2 ? afs_begin_vnode_operation+0x33/0x77 [kafs] ? afs_begin_vnode_operation+0x33/0x77 [kafs] ? afs_begin_vnode_operation+0x33/0x77 [kafs] afs_begin_vnode_operation+0x33/0x77 [kafs] afs_fetch_data+0x80/0x12a [kafs] afs_readpages+0x314/0x405 [kafs] __do_page_cache_readahead+0x203/0x2ba ? filemap_fault+0x179/0x54d filemap_fault+0x179/0x54d __do_fault+0x17/0x60 __handle_mm_fault+0x6d7/0x95c handle_mm_fault+0x24e/0x2a3 __do_page_fault+0x301/0x486 do_page_fault+0x236/0x259 page_fault+0x22/0x30 RIP: 0010:__clear_user+0x3d/0x60 RSP: 0018:ffff880071e93da0 EFLAGS: 00010202 RAX: 0000000000000000 RBX: 000000000000011c RCX: 000000000000011c RDX: 0000000000000000 RSI: 0000000000000008 RDI: 000000000060f720 RBP: 000000000060f720 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: ffff8800b5459b68 R12: ffff8800ce150e00 R13: 000000000060f720 R14: 00000000006127a8 R15: 0000000000000000 padzero+0x1c/0x2b load_elf_binary+0x785/0xdc7 search_binary_handler+0x81/0x1ff do_execveat_common.isra.14+0x600/0x888 do_execve+0x1f/0x21 SyS_execve+0x28/0x2f do_syscall_64+0x89/0x1be entry_SYSCALL64_slow_path+0x25/0x25 RIP: 0033:0x7fdb6009ee07 RSP: 002b:00007fff566d9728 EFLAGS: 00000246 ORIG_RAX: 000000000000003b RAX: ffffffffffffffda RBX: 000055ba57280900 RCX: 00007fdb6009ee07 RDX: 000055ba5727f270 RSI: 000055ba5727cac0 RDI: 000055ba57280900 RBP: 000055ba57280900 R08: 00007fff566d9700 R09: 0000000000000000 R10: 000055ba5727cac0 R11: 0000000000000246 R12: 0000000000000000 R13: 000055ba5727cac0 R14: 000055ba5727f270 R15: 0000000000000000 Signed-off-by: David Howells <dhowells@redhat.com>		2017-11-24 10:18:40 +00:00
..
6lowpan	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
9p	Merge branch '9p-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2017-11-22 20:17:54 -10:00
802	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
8021q	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net	2017-11-12 09:17:05 +09:00
appletalk	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
atm	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next	2017-11-15 11:56:19 -08:00
ax25	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net	2017-11-04 09:26:51 +09:00
batman-adv
bluetooth	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net	2017-11-04 09:26:51 +09:00
bpf
bridge	net: bridge: add vlan_tunnel to bridge port policies	2017-11-14 21:54:55 +09:00
caif	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
can	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net	2017-11-04 09:26:51 +09:00
ceph	We have a set of file locking improvements from Zheng, rbd rw/ro	2017-11-21 05:38:32 -10:00
core	Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf	2017-11-24 02:33:01 +09:00
dcb
dccp	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net	2017-11-04 09:26:51 +09:00
decnet	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next	2017-11-15 11:56:19 -08:00
dns_resolver
dsa	net: dsa: lan9303: calculate offload_fwd_mark from tag	2017-11-14 21:47:48 +09:00
ethernet
hsr
ieee802154	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net	2017-11-04 09:26:51 +09:00
ife
ipv4	net: accept UFO datagrams from tuntap and packet	2017-11-24 01:37:35 +09:00
ipv6	net: accept UFO datagrams from tuntap and packet	2017-11-24 01:37:35 +09:00
ipx	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net	2017-11-04 09:26:51 +09:00
iucv
kcm	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net	2017-11-04 09:26:51 +09:00
key	af_key: replace BUG_ON on WARN_ON in net_exit hook	2017-11-14 15:45:52 +09:00
l2tp	l2tp: exit_net cleanup check added	2017-11-14 15:45:53 +09:00
l3mdev
lapb
llc	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next	2017-11-15 11:56:19 -08:00
mac80211	mac80211: properly free requested-but-not-started TX agg sessions	2017-11-20 17:01:31 +01:00
mac802154	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net	2017-11-04 09:26:51 +09:00
mpls	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net	2017-11-04 09:26:51 +09:00
ncsi	net/ncsi: Don't return error on normal response	2017-11-11 15:09:44 +09:00
netfilter	netfilter: add ifdef around ctnetlink_proto_size	2017-11-16 10:49:00 +09:00
netlabel	net/netlabel: Add list_next_rcu() in rcu_dereference().	2017-11-18 10:32:41 +09:00
netlink	netlink: remove unnecessary forward declaration	2017-11-14 21:51:14 +09:00
netrom	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next	2017-11-15 11:56:19 -08:00
nfc	genetlink: fix genlmsg_nlhdr()	2017-11-16 10:49:00 +09:00
nsh	openvswitch: enable NSH support	2017-11-08 16:12:33 +09:00
openvswitch	net: accept UFO datagrams from tuntap and packet	2017-11-24 01:37:35 +09:00
packet	packet: exit_net cleanup check added	2017-11-14 15:45:52 +09:00
phonet	phonet: exit_net cleanup check added	2017-11-14 15:45:53 +09:00
psample
qrtr	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net	2017-11-10 10:00:18 +09:00
rds	Merge branch 'akpm' (patches from Andrew)	2017-11-15 19:42:40 -08:00
rfkill
rose
rxrpc	rxrpc: Provide a different lockdep key for call->user_mutex for kernel calls	2017-11-24 10:18:40 +00:00
sched	Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf	2017-11-24 02:33:01 +09:00
sctp	sctp: set frag_point in sctp_setsockopt_maxseg correctly	2017-11-18 10:32:41 +09:00
smc	net/smc: Fix preinitialization of buf_desc in __smc_buf_create()	2017-11-24 01:33:34 +09:00
strparser
sunrpc	Lots of good bugfixes, including:	2017-11-18 11:22:04 -08:00
switchdev	net: bridge: Add/del switchdev object on host join/leave	2017-11-10 13:41:40 +09:00
tipc	tipc: fix access of released memory	2017-11-21 20:22:03 +09:00
tls	tls: don't override sk_write_space if tls_set_sw_offload fails.	2017-11-14 16:26:35 +09:00
unix	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net	2017-11-04 09:26:51 +09:00
vmw_vsock	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net	2017-11-04 09:26:51 +09:00
wimax	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
wireless	cfg80211: initialize regulatory keys/database later	2017-11-20 16:55:29 +01:00
x25	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net	2017-11-04 09:26:51 +09:00
xfrm	Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec	2017-11-16 22:33:54 +09:00
compat.c
Kconfig
Makefile	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
socket.c	kmemcheck: remove annotations	2017-11-15 18:21:04 -08:00
sysctl_net.c