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021fd0f870
syzbot reported a recursive lock warning in rds_tcp_get_peer_sport() as
it calls inet6_getname() which acquires the socket lock that was already
held by __release_sock().
kworker/u8:6/2985 is trying to acquire lock:
ffff88807a07aa20 (k-sk_lock-AF_INET6){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1709 [inline]
ffff88807a07aa20 (k-sk_lock-AF_INET6){+.+.}-{0:0}, at: inet6_getname+0x15d/0x650 net/ipv6/af_inet6.c:533
but task is already holding lock:
ffff88807a07aa20 (k-sk_lock-AF_INET6){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1709 [inline]
ffff88807a07aa20 (k-sk_lock-AF_INET6){+.+.}-{0:0}, at: tcp_sock_set_cork+0x2c/0x2e0 net/ipv4/tcp.c:3694
lock_sock_nested+0x48/0x100 net/core/sock.c:3780
lock_sock include/net/sock.h:1709 [inline]
inet6_getname+0x15d/0x650 net/ipv6/af_inet6.c:533
rds_tcp_get_peer_sport net/rds/tcp_listen.c:70 [inline]
rds_tcp_conn_slots_available+0x288/0x470 net/rds/tcp_listen.c:149
rds_recv_hs_exthdrs+0x60f/0x7c0 net/rds/recv.c:265
rds_recv_incoming+0x9f6/0x12d0 net/rds/recv.c:389
rds_tcp_data_recv+0x7f1/0xa40 net/rds/tcp_recv.c:243
__tcp_read_sock+0x196/0x970 net/ipv4/tcp.c:1702
rds_tcp_read_sock net/rds/tcp_recv.c:277 [inline]
rds_tcp_data_ready+0x369/0x950 net/rds/tcp_recv.c:331
tcp_rcv_established+0x19e9/0x2670 net/ipv4/tcp_input.c:6675
tcp_v6_do_rcv+0x8eb/0x1ba0 net/ipv6/tcp_ipv6.c:1609
sk_backlog_rcv include/net/sock.h:1185 [inline]
__release_sock+0x1b8/0x3a0 net/core/sock.c:3213
Reading from the socket struct directly is safe from possible paths. For
rds_tcp_accept_one(), the socket has just been accepted and is not yet
exposed to concurrent access. For rds_tcp_conn_slots_available(), direct
access avoids the recursive deadlock seen during backlog processing
where the socket lock is already held from the __release_sock().
However, rds_tcp_conn_slots_available() is also called from the normal
softirq path via tcp_data_ready() where the lock is not held. This is
also safe because inet_dport is a stable 16 bits field. A READ_ONCE()
annotation as the value might be accessed lockless in a concurrent
access context.
Note that it is also safe to call rds_tcp_conn_slots_available() from
rds_conn_shutdown() because the fan-out is disabled.
Fixes:
|
||
|---|---|---|
| .. | ||
| 6lowpan | ||
| 9p | ||
| 802 | ||
| 8021q | ||
| appletalk | ||
| atm | ||
| ax25 | ||
| batman-adv | ||
| bluetooth | ||
| bpf | ||
| bridge | ||
| caif | ||
| can | ||
| ceph | ||
| core | ||
| dcb | ||
| 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 | ||
| psp | ||
| qrtr | ||
| rds | ||
| rfkill | ||
| rose | ||
| rxrpc | ||
| sched | ||
| sctp | ||
| shaper | ||
| 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 | ||