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234ec0b603
I analyze the potential sleeping issue of the following processes:
Thread A Thread B
... netlink_create //ref = 1
do_mq_notify ...
sock = netlink_getsockbyfilp ... //ref = 2
info->notify_sock = sock; ...
... netlink_sendmsg
... skb = netlink_alloc_large_skb //skb->head is vmalloced
... netlink_unicast
... sk = netlink_getsockbyportid //ref = 3
... netlink_sendskb
... __netlink_sendskb
... skb_queue_tail //put skb to sk_receive_queue
... sock_put //ref = 2
... ...
... netlink_release
... deferred_put_nlk_sk //ref = 1
mqueue_flush_file
spin_lock
remove_notification
netlink_sendskb
sock_put //ref = 0
sk_free
...
__sk_destruct
netlink_sock_destruct
skb_queue_purge //get skb from sk_receive_queue
...
__skb_queue_purge_reason
kfree_skb_reason
__kfree_skb
...
skb_release_all
skb_release_head_state
netlink_skb_destructor
vfree(skb->head) //sleeping while holding spinlock
In netlink_sendmsg, if the memory pointed to by skb->head is allocated by
vmalloc, and is put to sk_receive_queue queue, also the skb is not freed.
When the mqueue executes flush, the sleeping bug will occur. Use
vfree_atomic instead of vfree in netlink_skb_destructor to solve the issue.
Fixes:
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---|---|---|
.. | ||
6lowpan | ||
9p | ||
802 | ||
8021q | ||
appletalk | ||
atm | ||
ax25 | ||
batman-adv | ||
bluetooth | ||
bpf | ||
bridge | ||
caif | ||
can | ||
ceph | ||
core | ||
dcb | ||
dccp | ||
devlink | ||
dns_resolver | ||
dsa | ||
ethernet | ||
ethtool | ||
handshake | ||
hsr | ||
ieee802154 | ||
ife | ||
ipv4 | ||
ipv6 | ||
iucv | ||
kcm | ||
key | ||
l2tp | ||
l3mdev | ||
lapb | ||
llc | ||
mac80211 | ||
mac802154 | ||
mctp | ||
mpls | ||
mptcp | ||
ncsi | ||
netfilter | ||
netlabel | ||
netlink | ||
netrom | ||
nfc | ||
nsh | ||
openvswitch | ||
packet | ||
phonet | ||
psample | ||
qrtr | ||
rds | ||
rfkill | ||
rose | ||
rxrpc | ||
sched | ||
sctp | ||
smc | ||
strparser | ||
sunrpc | ||
switchdev | ||
tipc | ||
tls | ||
unix | ||
vmw_vsock | ||
wireless | ||
x25 | ||
xdp | ||
xfrm | ||
compat.c | ||
devres.c | ||
Kconfig | ||
Kconfig.debug | ||
Makefile | ||
socket.c | ||
sysctl_net.c |