linux/net
Florian Westphal 0470eb99b4 netlink: don't hold mutex in rcu callback when releasing mmapd ring
Kirill A. Shutemov says:

This simple test-case trigers few locking asserts in kernel:

int main(int argc, char **argv)
{
        unsigned int block_size = 16 * 4096;
        struct nl_mmap_req req = {
                .nm_block_size          = block_size,
                .nm_block_nr            = 64,
                .nm_frame_size          = 16384,
                .nm_frame_nr            = 64 * block_size / 16384,
        };
        unsigned int ring_size;
	int fd;

	fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_GENERIC);
        if (setsockopt(fd, SOL_NETLINK, NETLINK_RX_RING, &req, sizeof(req)) < 0)
                exit(1);
        if (setsockopt(fd, SOL_NETLINK, NETLINK_TX_RING, &req, sizeof(req)) < 0)
                exit(1);

	ring_size = req.nm_block_nr * req.nm_block_size;
	mmap(NULL, 2 * ring_size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
	return 0;
}

+++ exited with 0 +++
BUG: sleeping function called from invalid context at /home/kas/git/public/linux-mm/kernel/locking/mutex.c:616
in_atomic(): 1, irqs_disabled(): 0, pid: 1, name: init
3 locks held by init/1:
 #0:  (reboot_mutex){+.+...}, at: [<ffffffff81080959>] SyS_reboot+0xa9/0x220
 #1:  ((reboot_notifier_list).rwsem){.+.+..}, at: [<ffffffff8107f379>] __blocking_notifier_call_chain+0x39/0x70
 #2:  (rcu_callback){......}, at: [<ffffffff810d32e0>] rcu_do_batch.isra.49+0x160/0x10c0
Preemption disabled at:[<ffffffff8145365f>] __delay+0xf/0x20

CPU: 1 PID: 1 Comm: init Not tainted 4.1.0-00009-gbddf4c4818e0 #253
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS Debian-1.8.2-1 04/01/2014
 ffff88017b3d8000 ffff88027bc03c38 ffffffff81929ceb 0000000000000102
 0000000000000000 ffff88027bc03c68 ffffffff81085a9d 0000000000000002
 ffffffff81ca2a20 0000000000000268 0000000000000000 ffff88027bc03c98
Call Trace:
 <IRQ>  [<ffffffff81929ceb>] dump_stack+0x4f/0x7b
 [<ffffffff81085a9d>] ___might_sleep+0x16d/0x270
 [<ffffffff81085bed>] __might_sleep+0x4d/0x90
 [<ffffffff8192e96f>] mutex_lock_nested+0x2f/0x430
 [<ffffffff81932fed>] ? _raw_spin_unlock_irqrestore+0x5d/0x80
 [<ffffffff81464143>] ? __this_cpu_preempt_check+0x13/0x20
 [<ffffffff8182fc3d>] netlink_set_ring+0x1ed/0x350
 [<ffffffff8182e000>] ? netlink_undo_bind+0x70/0x70
 [<ffffffff8182fe20>] netlink_sock_destruct+0x80/0x150
 [<ffffffff817e484d>] __sk_free+0x1d/0x160
 [<ffffffff817e49a9>] sk_free+0x19/0x20
[..]

Cong Wang says:

We can't hold mutex lock in a rcu callback, [..]

Thomas Graf says:

The socket should be dead at this point. It might be simpler to
add a netlink_release_ring() function which doesn't require
locking at all.

Reported-by: "Kirill A. Shutemov" <kirill@shutemov.name>
Diagnosed-by: Cong Wang <cwang@twopensource.com>
Suggested-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-07-21 22:22:56 -07:00
..
6lowpan
9p Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-07-04 19:36:06 -07:00
802
8021q vlan: Add GRO support for non hardware accelerated vlan 2015-06-01 16:50:52 -07:00
appletalk net: Pass kern from net_proto_family.create to sk_alloc 2015-05-11 10:50:17 -04:00
atm net: Pass kern from net_proto_family.create to sk_alloc 2015-05-11 10:50:17 -04:00
ax25 NET: AX.25: Stop heartbeat timer on disconnect. 2015-07-15 15:59:58 -07:00
batman-adv batman-adv: change the MAC of each VLAN upon ndo_set_mac_address 2015-06-07 17:07:20 +02:00
bluetooth bluetooth: fix list handling 2015-07-04 19:11:33 -07:00
bridge bridge: mdb: fix double add notification 2015-07-15 17:15:01 -07:00
caif caif: fix leaks and race in caif_queue_rcv_skb() 2015-07-21 00:02:44 -07:00
can can: replace timestamp as unique skb attribute 2015-07-12 21:13:22 +02:00
ceph libceph: treat sockaddr_storage with uninitialized family as blank 2015-07-09 20:30:34 +03:00
core net: ratelimit warnings about dst entry refcount underflow or overflow 2015-07-21 00:11:19 -07:00
dcb
dccp sock_diag: specify info_size per inet protocol 2015-06-15 19:49:22 -07:00
decnet net: Pass kern from net_proto_family.create to sk_alloc 2015-05-11 10:50:17 -04:00
dns_resolver
dsa net: dsa: Fix off-by-one in switch address parsing 2015-07-11 23:25:16 -07:00
ethernet net: Add full IPv6 addresses to flow_keys 2015-06-04 15:44:30 -07:00
hsr
ieee802154 nl802154: export supported commands 2015-06-04 12:27:15 +02:00
ipv4 tcp: suppress a division by zero warning 2015-07-21 22:13:13 -07:00
ipv6 Revert "sit: Add gro callbacks to sit_offload" 2015-07-20 16:52:28 -07:00
ipx net: Pass kern from net_proto_family.create to sk_alloc 2015-05-11 10:50:17 -04:00
irda irda: use msecs_to_jiffies for conversion to jiffies 2015-05-25 17:46:21 -04:00
iucv net: Pass kern from net_proto_family.create to sk_alloc 2015-05-11 10:50:17 -04:00
key Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2015-06-24 16:49:49 -07:00
l2tp net: Modify sk_alloc to not reference count the netns of kernel sockets. 2015-05-11 10:50:18 -04:00
lapb
llc net: Pass kern from net_proto_family.create to sk_alloc 2015-05-11 10:50:17 -04:00
mac80211 cfg80211: use RTNL locked reg_can_beacon for IR-relaxation 2015-07-17 15:02:02 +02:00
mac802154 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2015-06-24 16:49:49 -07:00
mpls Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-06-13 23:56:52 -07:00
netfilter netfilter: nfnetlink: keep going batch handling on missing modules 2015-07-02 17:59:33 +02:00
netlabel
netlink netlink: don't hold mutex in rcu callback when releasing mmapd ring 2015-07-21 22:22:56 -07:00
netrom netfilter: Remove spurios included of netfilter.h 2015-06-18 21:14:32 +02:00
nfc NFC: nci: fix mistake in uart generic driver 2015-06-15 18:10:37 +02:00
openvswitch Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-06-08 20:06:56 -07:00
packet Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-06-24 02:58:51 -07:00
phonet net: Pass kern from net_proto_family.create to sk_alloc 2015-05-11 10:50:17 -04:00
rds net-RDS: Delete an unnecessary check before the function call "module_put" 2015-07-03 09:27:42 -07:00
rfkill net: rfkill: gpio: make better use of gpiod API 2015-05-29 13:13:45 +02:00
rose Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-06-24 02:58:51 -07:00
rxrpc net: Pass kern from net_proto_family.create to sk_alloc 2015-05-11 10:50:17 -04:00
sched sched: cls_flow: fix panic on filter replace 2015-07-21 00:25:03 -07:00
sctp sctp: Fix race between OOTB responce and route removal 2015-06-29 09:28:42 -07:00
sunrpc NFS client updates for Linux 4.2 2015-07-02 11:32:23 -07:00
switchdev net: switchdev: don't abort unsupported operations 2015-07-11 21:29:55 -07:00
tipc net/tipc: initialize security state for new connection socket 2015-07-08 16:08:23 -07:00
unix net/unix: support SCM_SECURITY for stream sockets 2015-06-10 22:49:20 -07:00
vmw_vsock net: Pass kern from net_proto_family.create to sk_alloc 2015-05-11 10:50:17 -04:00
wimax
wireless cfg80211: use RTNL locked reg_can_beacon for IR-relaxation 2015-07-17 15:02:02 +02:00
x25 net: Pass kern from net_proto_family.create to sk_alloc 2015-05-11 10:50:17 -04:00
xfrm Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2015-06-24 16:49:49 -07:00
compat.c
Kconfig net: add CONFIG_NET_INGRESS to enable ingress filtering 2015-05-14 01:10:05 -04:00
Makefile
socket.c net: Add a struct net parameter to sock_create_kern 2015-05-11 10:50:17 -04:00
sysctl_net.c