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fff4f776df
linux/net
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Nikolay Aleksandrov fff4f776df ip6mr: fix stale iterator 
[ Upstream commit 4adfa79fc2 ]

When we dump the ip6mr mfc entries via proc, we initialize an iterator
with the table to dump but we don't clear the cache pointer which might
be initialized from a prior read on the same descriptor that ended. This
can result in lock imbalance (an unnecessary unlock) leading to other
crashes and hangs. Clear the cache pointer like ipmr does to fix the issue.
Thanks for the reliable reproducer.

Here's syzbot's trace:
 WARNING: bad unlock balance detected!
 4.15.0-rc3+ #128 Not tainted
 syzkaller971460/3195 is trying to release lock (mrt_lock) at:
 [<000000006898068d>] ipmr_mfc_seq_stop+0xe1/0x130 net/ipv6/ip6mr.c:553
 but there are no more locks to release!

 other info that might help us debug this:
 1 lock held by syzkaller971460/3195:
  #0:  (&p->lock){+.+.}, at: [<00000000744a6565>] seq_read+0xd5/0x13d0
 fs/seq_file.c:165

 stack backtrace:
 CPU: 1 PID: 3195 Comm: syzkaller971460 Not tainted 4.15.0-rc3+ #128
 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
 Google 01/01/2011
 Call Trace:
  __dump_stack lib/dump_stack.c:17 [inline]
  dump_stack+0x194/0x257 lib/dump_stack.c:53
  print_unlock_imbalance_bug+0x12f/0x140 kernel/locking/lockdep.c:3561
  __lock_release kernel/locking/lockdep.c:3775 [inline]
  lock_release+0x5f9/0xda0 kernel/locking/lockdep.c:4023
  __raw_read_unlock include/linux/rwlock_api_smp.h:225 [inline]
  _raw_read_unlock+0x1a/0x30 kernel/locking/spinlock.c:255
  ipmr_mfc_seq_stop+0xe1/0x130 net/ipv6/ip6mr.c:553
  traverse+0x3bc/0xa00 fs/seq_file.c:135
  seq_read+0x96a/0x13d0 fs/seq_file.c:189
  proc_reg_read+0xef/0x170 fs/proc/inode.c:217
  do_loop_readv_writev fs/read_write.c:673 [inline]
  do_iter_read+0x3db/0x5b0 fs/read_write.c:897
  compat_readv+0x1bf/0x270 fs/read_write.c:1140
  do_compat_preadv64+0xdc/0x100 fs/read_write.c:1189
  C_SYSC_preadv fs/read_write.c:1209 [inline]
  compat_SyS_preadv+0x3b/0x50 fs/read_write.c:1203
  do_syscall_32_irqs_on arch/x86/entry/common.c:327 [inline]
  do_fast_syscall_32+0x3ee/0xf9d arch/x86/entry/common.c:389
  entry_SYSENTER_compat+0x51/0x60 arch/x86/entry/entry_64_compat.S:125
 RIP: 0023:0xf7f73c79
 RSP: 002b:00000000e574a15c EFLAGS: 00000292 ORIG_RAX: 000000000000014d
 RAX: ffffffffffffffda RBX: 000000000000000f RCX: 0000000020a3afb0
 RDX: 0000000000000001 RSI: 0000000000000067 RDI: 0000000000000000
 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 BUG: sleeping function called from invalid context at lib/usercopy.c:25
 in_atomic(): 1, irqs_disabled(): 0, pid: 3195, name: syzkaller971460
 INFO: lockdep is turned off.
 CPU: 1 PID: 3195 Comm: syzkaller971460 Not tainted 4.15.0-rc3+ #128
 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
 Google 01/01/2011
 Call Trace:
  __dump_stack lib/dump_stack.c:17 [inline]
  dump_stack+0x194/0x257 lib/dump_stack.c:53
  ___might_sleep+0x2b2/0x470 kernel/sched/core.c:6060
  __might_sleep+0x95/0x190 kernel/sched/core.c:6013
  __might_fault+0xab/0x1d0 mm/memory.c:4525
  _copy_to_user+0x2c/0xc0 lib/usercopy.c:25
  copy_to_user include/linux/uaccess.h:155 [inline]
  seq_read+0xcb4/0x13d0 fs/seq_file.c:279
  proc_reg_read+0xef/0x170 fs/proc/inode.c:217
  do_loop_readv_writev fs/read_write.c:673 [inline]
  do_iter_read+0x3db/0x5b0 fs/read_write.c:897
  compat_readv+0x1bf/0x270 fs/read_write.c:1140
  do_compat_preadv64+0xdc/0x100 fs/read_write.c:1189
  C_SYSC_preadv fs/read_write.c:1209 [inline]
  compat_SyS_preadv+0x3b/0x50 fs/read_write.c:1203
  do_syscall_32_irqs_on arch/x86/entry/common.c:327 [inline]
  do_fast_syscall_32+0x3ee/0xf9d arch/x86/entry/common.c:389
  entry_SYSENTER_compat+0x51/0x60 arch/x86/entry/entry_64_compat.S:125
 RIP: 0023:0xf7f73c79
 RSP: 002b:00000000e574a15c EFLAGS: 00000292 ORIG_RAX: 000000000000014d
 RAX: ffffffffffffffda RBX: 000000000000000f RCX: 0000000020a3afb0
 RDX: 0000000000000001 RSI: 0000000000000067 RDI: 0000000000000000
 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 WARNING: CPU: 1 PID: 3195 at lib/usercopy.c:26 _copy_to_user+0xb5/0xc0
 lib/usercopy.c:26

Reported-by: syzbot <bot+eceb3204562c41a438fa1f2335e0fe4f6886d669@syzkaller.appspotmail.com>
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-02-16 20:09:37 +01:00
..
6lowpan 6lowpan: put mcast compression in an own function 2015-10-21 00:49:25 +02:00
9p net/9p: Switch to wait_event_killable() 2017-11-30 08:37:25 +00:00
802
8021q 8021q: fix a memory leak for VLAN 0 device 2018-01-17 09:35:29 +01:00
appletalk
atm atm: deal with setting entry before mkip was called 2015-09-17 22:13:32 -07:00
ax25 ax25: Fix segfault after sock connection timeout 2017-02-04 09:45:09 +01:00
batman-adv batman-adv: Check for alloc errors when preparing TT local data 2016-12-15 08:49:23 -08:00
bluetooth Bluetooth: Prevent stack info leak from the EFS element. 2018-01-17 09:35:32 +01:00
bridge net: bridge: fix early call to br_stp_change_bridge_id and plug newlink leaks 2018-01-02 20:33:26 +01:00
caif net: caif: Fix a sleep-in-atomic bug in cfpkt_create_pfx 2017-07-05 14:37:14 +02:00
can can: af_can: canfd_rcv(): replace WARN_ONCE by pr_warn_once 2018-01-31 12:06:08 +01:00
ceph libceph: force GFP_NOIO for socket allocations 2017-04-08 09:53:30 +02:00
core bpf: fix 32-bit divide by zero 2018-02-03 17:04:25 +01:00
dcb net/dcb: make dcbnl.c explicitly non-modular 2015-10-09 07:52:27 -07:00
dccp dccp: don't restart ccid2_hc_tx_rto_expire() if sk in closed state 2018-01-31 12:06:12 +01:00
decnet decnet: always not take dst->__refcnt when inserting dst into hash table 2017-07-05 14:37:14 +02:00
dns_resolver KEYS: Fix race between updating and finding a negative key 2017-10-27 10:23:18 +02:00
dsa net: dsa: select NET_SWITCHDEV 2017-11-15 17:13:11 +01:00
ethernet net: introduce device min_header_len 2017-02-18 16:39:27 +01:00
hsr net/hsr: fix a warning message 2015-11-23 14:56:15 -05:00
ieee802154 Revert "net: fix percpu memory leaks" 2017-09-27 11:00:11 +02:00
ipv4 net: tcp: close sock if net namespace is exiting 2018-01-31 12:06:14 +01:00
ipv6 ip6mr: fix stale iterator 2018-02-16 20:09:37 +01:00
ipx ipx: call ipxitf_put() in ioctl error path 2017-05-25 14:30:13 +02:00
irda irda: do not leak initialized list.dev to userspace 2017-08-30 10:19:21 +02:00
iucv af_iucv: Validate socket address length in iucv_sock_bind() 2016-03-03 15:07:03 -08:00
key af_key: fix buffer overread in parse_exthdrs() 2018-01-23 19:50:14 +01:00
l2tp l2tp: cleanup l2tp_tunnel_delete calls 2017-12-20 10:04:59 +01:00
l3mdev net: Add netif_is_l3_slave 2015-10-07 04:27:43 -07:00
lapb
llc net/llc: avoid BUG_ON() in skb_orphan() 2017-02-26 11:07:49 +01:00
mac80211 mac80211: fix the update of path metric for RANN frame 2018-02-03 17:04:27 +01:00
mac802154 mac802154: llsec: use kzfree 2015-10-21 00:49:24 +02:00
mpls mpls: Send route delete notifications when router module is unloaded 2017-03-22 12:04:16 +01:00
netfilter netfilter: xt_osf: Add missing permission checks 2018-01-31 12:06:11 +01:00
netlabel netlabel: add address family checks to netlbl_{sock,req}_delattr() 2016-08-20 18:09:22 +02:00
netlink netlink: Add netns check on taps 2018-01-02 20:33:24 +01:00
netrom
nfc NFC: fix device-allocation error return 2017-11-30 08:37:23 +00:00
openvswitch openvswitch: fix the incorrect flow action alloc size 2018-02-03 17:04:27 +01:00
packet net/packet: fix a race in packet_bind() and packet_notifier() 2017-12-16 10:33:56 +01:00
phonet phonet: properly unshare skbs in phonet_rcv() 2016-01-31 11:29:00 -08:00
rds RDS: null pointer dereference in rds_atomic_free_op 2018-01-17 09:35:29 +01:00
rfkill rfkill: fix rfkill_fop_read wait_event usage 2016-03-03 15:07:26 -08:00
rose
rxrpc rxrpc: Fix several cases where a padded len isn't checked in ticket decode 2017-06-29 12:48:52 +02:00
sched sch_dsmark: fix invalid skb_cow() usage 2017-12-25 14:22:10 +01:00
sctp sctp: return error if the asoc has been peeled off in sctp_wait_for_sndbuf 2018-01-31 12:06:13 +01:00
sunrpc SUNRPC: Allow connect to return EHOSTUNREACH 2018-02-03 17:04:28 +01:00
switchdev switchdev: pass pointer to fib_info instead of copy 2016-06-24 10:18:16 -07:00
tipc tipc: fix memory leak in tipc_accept_from_sock() 2017-12-16 10:33:56 +01:00
unix net/unix: don't show information about sockets from other namespaces 2017-11-18 11:11:06 +01:00
vmw_vsock vsock: use new wait API for vsock_stream_sendmsg() 2017-11-30 08:37:19 +00:00
wimax net:wimax: Fix doucble word "the the" in networking.xml 2015-08-09 22:43:52 -07:00
wireless nl80211: Define policy for packet pattern attributes 2017-10-18 09:20:41 +02:00
x25 net: fix a kernel infoleak in x25 module 2016-05-18 17:06:43 -07:00
xfrm xfrm: Copy policy family in clone_policy 2017-12-16 10:33:55 +01:00
compat.c audit: log 32-bit socketcalls 2017-10-08 10:14:18 +02:00
Kconfig bpf: introduce BPF_JIT_ALWAYS_ON config 2018-02-03 17:04:24 +01:00
Makefile net: Introduce L3 Master device abstraction 2015-09-29 20:40:32 -07:00
socket.c bpf: introduce BPF_JIT_ALWAYS_ON config 2018-02-03 17:04:24 +01:00
sysctl_net.c net: Use ns_capable_noaudit() when determining net sysctl permissions 2016-09-15 08:27:50 +02:00