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db6a5018b6
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Jakub Sitnicki db6a5018b6 bpf, sockmap: Don't sleep while holding RCU lock on tear-down 
rcu_read_lock is needed to protect access to psock inside sock_map_unref
when tearing down the map. However, we can't afford to sleep in lock_sock
while in RCU read-side critical section. Grab the RCU lock only after we
have locked the socket.

This fixes RCU warnings triggerable on a VM with 1 vCPU when free'ing a
sockmap/sockhash that contains at least one socket:

| =============================
| WARNING: suspicious RCU usage
| 5.5.0-04005-g8fc91b972b73 #450 Not tainted
| -----------------------------
| include/linux/rcupdate.h:272 Illegal context switch in RCU read-side critical section!
|
| other info that might help us debug this:
|
|
| rcu_scheduler_active = 2, debug_locks = 1
| 4 locks held by kworker/0:1/62:
|  #0: ffff88813b019748 ((wq_completion)events){+.+.}, at: process_one_work+0x1d7/0x5e0
|  #1: ffffc900000abe50 ((work_completion)(&map->work)){+.+.}, at: process_one_work+0x1d7/0x5e0
|  #2: ffffffff82065d20 (rcu_read_lock){....}, at: sock_map_free+0x5/0x170
|  #3: ffff8881368c5df8 (&stab->lock){+...}, at: sock_map_free+0x64/0x170
|
| stack backtrace:
| CPU: 0 PID: 62 Comm: kworker/0:1 Not tainted 5.5.0-04005-g8fc91b972b73 #450
| Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_073836-buildvm-ppc64le-16.ppc.fedoraproject.org-3.fc31 04/01/2014
| Workqueue: events bpf_map_free_deferred
| Call Trace:
|  dump_stack+0x71/0xa0
|  ___might_sleep+0x105/0x190
|  lock_sock_nested+0x28/0x90
|  sock_map_free+0x95/0x170
|  bpf_map_free_deferred+0x58/0x80
|  process_one_work+0x260/0x5e0
|  worker_thread+0x4d/0x3e0
|  kthread+0x108/0x140
|  ? process_one_work+0x5e0/0x5e0
|  ? kthread_park+0x90/0x90
|  ret_from_fork+0x3a/0x50

| =============================
| WARNING: suspicious RCU usage
| 5.5.0-04005-g8fc91b972b73-dirty #452 Not tainted
| -----------------------------
| include/linux/rcupdate.h:272 Illegal context switch in RCU read-side critical section!
|
| other info that might help us debug this:
|
|
| rcu_scheduler_active = 2, debug_locks = 1
| 4 locks held by kworker/0:1/62:
|  #0: ffff88813b019748 ((wq_completion)events){+.+.}, at: process_one_work+0x1d7/0x5e0
|  #1: ffffc900000abe50 ((work_completion)(&map->work)){+.+.}, at: process_one_work+0x1d7/0x5e0
|  #2: ffffffff82065d20 (rcu_read_lock){....}, at: sock_hash_free+0x5/0x1d0
|  #3: ffff888139966e00 (&htab->buckets[i].lock){+...}, at: sock_hash_free+0x92/0x1d0
|
| stack backtrace:
| CPU: 0 PID: 62 Comm: kworker/0:1 Not tainted 5.5.0-04005-g8fc91b972b73-dirty #452
| Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_073836-buildvm-ppc64le-16.ppc.fedoraproject.org-3.fc31 04/01/2014
| Workqueue: events bpf_map_free_deferred
| Call Trace:
|  dump_stack+0x71/0xa0
|  ___might_sleep+0x105/0x190
|  lock_sock_nested+0x28/0x90
|  sock_hash_free+0xec/0x1d0
|  bpf_map_free_deferred+0x58/0x80
|  process_one_work+0x260/0x5e0
|  worker_thread+0x4d/0x3e0
|  kthread+0x108/0x140
|  ? process_one_work+0x5e0/0x5e0
|  ? kthread_park+0x90/0x90
|  ret_from_fork+0x3a/0x50

Fixes: 7e81a35302 ("bpf: Sockmap, ensure sock lock held during tear down")
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200206111652.694507-2-jakub@cloudflare.com
2020-02-07 22:36:26 +01:00
..
6lowpan
9p 9p pull request for inclusion in 5.4 2019-09-27 15:10:34 -07:00
802 treewide: Use sizeof_field() macro 2019-12-09 10:36:44 -08:00
8021q Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-01-09 12:13:43 -08:00
appletalk appletalk: enforce CAP_NET_RAW for raw sockets 2019-09-24 16:37:18 +02:00
atm Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-01-26 10:40:21 +01:00
ax25 net: Make sock protocol value checks more specific 2020-01-09 18:41:40 -08:00
batman-adv Merge ra.kernel.org:/pub/scm/linux/kernel/git/netdev/net 2020-01-19 22:10:04 +01:00
bluetooth Bluetooth: Fix race condition in hci_release_sock() 2020-01-26 10:34:17 +02:00
bpf bpf: Allow to change skb mark in test_run 2019-12-18 17:05:58 -08:00
bpfilter
bridge net: bridge: vlan: add per-vlan state 2020-01-24 12:58:14 +01:00
caif caif_usb: fix spelling mistake "to" -> "too" 2020-01-24 08:12:06 +01:00
can can: j1939: j1939_sk_bind(): take priv after lock is held 2019-12-08 11:52:02 +01:00
ceph libceph, rbd, ceph: convert to use the new mount API 2019-11-27 22:28:37 +01:00
core bpf, sockmap: Don't sleep while holding RCU lock on tear-down 2020-02-07 22:36:26 +01:00
dcb
dccp treewide: Use sizeof_field() macro 2019-12-09 10:36:44 -08:00
decnet net: Make sock protocol value checks more specific 2020-01-09 18:41:40 -08:00
dns_resolver
dsa net: dsa: Fix use-after-free in probing of DSA switch tree 2020-01-27 11:12:46 +01:00
ethernet net: remove eth_change_mtu 2020-01-27 11:09:31 +01:00
ethtool net/core: Replace driver version to be kernel version 2020-01-27 13:47:22 +01:00
hsr net/hsr: remove seq_nr_after_or_eq 2020-01-21 12:03:21 +01:00
ieee802154 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-11-02 13:54:56 -07:00
ife net: Fix Kconfig indentation 2019-09-26 08:56:17 +02:00
ipv4 udp: Support UDP fraglist GRO/GSO. 2020-01-27 11:00:21 +01:00
ipv6 udp: Support UDP fraglist GRO/GSO. 2020-01-27 11:00:21 +01:00
iucv treewide: Use sizeof_field() macro 2019-12-09 10:36:44 -08:00
kcm kcm: disable preemption in kcm_parse_func_strparser() 2019-09-27 10:27:14 +02:00
key
l2tp l2tp: Remove redundant BUG_ON() check in l2tp_pernet 2020-01-03 12:26:07 -08:00
l3mdev
lapb
llc llc2: Fix return statement of llc_stat_ev_rx_null_dsap_xid_c (and _test_c) 2019-12-20 21:19:36 -08:00
mac80211 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 2020-01-28 16:02:33 -08:00
mac802154
mpls net: ipv6_stub: use ip6_dst_lookup_flow instead of ip6_dst_lookup 2019-12-04 12:27:13 -08:00
mptcp mptcp: Fix build with PROC_FS disabled. 2020-01-29 10:39:23 +01:00
ncsi net/ncsi: Support for multi host mellanox card 2020-01-09 18:36:22 -08:00
netfilter nf_tables: Add set type for arbitrary concatenation of ranges 2020-01-27 08:54:30 +01:00
netlabel netlabel: remove redundant assignment to pointer iter 2019-09-01 11:45:02 -07:00
netlink treewide: Use sizeof_field() macro 2019-12-09 10:36:44 -08:00
netrom net: core: add generic lockdep keys 2019-10-24 14:53:48 -07:00
nfc net: nfc: nci: fix a possible sleep-in-atomic-context bug in nci_uart_tty_receive() 2019-12-18 11:57:33 -08:00
nsh
openvswitch net: openvswitch: use skb_list_walk_safe helper for gso segments 2020-01-14 11:48:41 -08:00
packet af_packet: refactoring code for prb_calc_retire_blk_tmo 2019-12-26 15:19:59 -08:00
phonet net: Remove redundant BUG_ON() check in phonet_pernet 2020-01-03 12:25:50 -08:00
psample net: psample: fix skb_over_panic 2019-11-26 14:40:13 -08:00
qrtr net: qrtr: Remove receive worker 2020-01-14 18:36:42 -08:00
rds net/rds: Use prefetch for On-Demand-Paging MR 2020-01-18 11:48:19 +02:00
rfkill rfkill: Fix incorrect check to avoid NULL pointer dereference 2019-12-16 10:15:49 +01:00
rose Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-01-26 10:40:21 +01:00
rxrpc rxrpc: Fix use-after-free in rxrpc_receive_data() 2020-01-27 10:56:30 +01:00
sched sch_choke: Use kvcalloc 2020-01-29 11:58:10 +01:00
sctp Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-01-09 12:13:43 -08:00
smc net/smc: allow unprivileged users to read pnet table 2020-01-21 11:39:56 +01:00
strparser
sunrpc xprtrdma: Fix oops in Receive handler after device removal 2020-01-14 13:30:24 -05:00
switchdev
tipc Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 2020-01-28 16:02:33 -08:00
tls Merge ra.kernel.org:/pub/scm/linux/kernel/git/netdev/net 2020-01-19 22:10:04 +01:00
unix Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next 2020-01-21 12:18:20 +01:00
vmw_vsock Merge ra.kernel.org:/pub/scm/linux/kernel/git/netdev/net 2020-01-19 22:10:04 +01:00
wimax
wireless Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 2020-01-28 16:02:33 -08:00
x25 net/x25: fix nonblocking connect 2020-01-09 18:39:33 -08:00
xdp xsk, net: Make sock_def_readable() have external linkage 2020-01-22 00:08:52 +01:00
xfrm Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-01-26 10:40:21 +01:00
compat.c y2038: socket: use __kernel_old_timespec instead of timespec 2019-11-15 14:38:29 +01:00
Kconfig mptcp: Add MPTCP socket stubs 2020-01-24 13:44:07 +01:00
Makefile mptcp: Add MPTCP socket stubs 2020-01-24 13:44:07 +01:00
socket.c socket: fix unused-function warning 2020-01-08 15:02:21 -08:00
sysctl_net.c