freebsd-dev/sys/netgraph
Robert Watson 81158452be Push acquisition of the accept mutex out of sofree() into the caller
(sorele()/sotryfree()):

- This permits the caller to acquire the accept mutex before the socket
  mutex, avoiding sofree() having to drop the socket mutex and re-order,
  which could lead to races permitting more than one thread to enter
  sofree() after a socket is ready to be free'd.

- This also covers clearing of the so_pcb weak socket reference from
  the protocol to the socket, preventing races in clearing and
  evaluation of the reference such that sofree() might be called more
  than once on the same socket.

This appears to close a race I was able to easily trigger by repeatedly
opening and resetting TCP connections to a host, in which the
tcp_close() code called as a result of the RST raced with the close()
of the accepted socket in the user process resulting in simultaneous
attempts to de-allocate the same socket.  The new locking increases
the overhead for operations that may potentially free the socket, so we
will want to revise the synchronization strategy here as we normalize
the reference counting model for sockets.  The use of the accept mutex
in freeing of sockets that are not listen sockets is primarily
motivated by the potential need to remove the socket from the
incomplete connection queue on its parent (listen) socket, so cleaning
up the reference model here may allow us to substantially weaken the
synchronization requirements.

RELENG_5_3 candidate.

MFC after:	3 days
Reviewed by:	dwhite
Discussed with:	gnn, dwhite, green
Reported by:	Marc UBM Bocklet <ubm at u-boot-man dot de>
Reported by:	Vlad <marchenko at gmail dot com>
2004-10-18 22:19:43 +00:00
..
atm Apply error and success logic consistently to the function netisr_queue() and 2004-08-27 18:33:08 +00:00
bluetooth Push acquisition of the accept mutex out of sofree() into the caller 2004-10-18 22:19:43 +00:00
netflow - Remove advertising clause from copyright [1] 2004-09-17 19:58:03 +00:00
netgraph.h Align netgraph message fields ready for 64-bit (and 128 bit :-) machines. 2004-08-20 01:24:23 +00:00
ng_async.c Consistently use __inline instead of __inline__ as the former is an empty macro 2004-07-04 16:11:03 +00:00
ng_async.h
ng_atmllc.c Switch to using C99 sparse initialisers for the type methods array. 2004-05-29 00:51:19 +00:00
ng_atmllc.h Add a netgraph node to handle ATM LLC encapsulation. This currently handles 2004-03-08 10:54:35 +00:00
ng_base.c When making a peer of unknown type framework tries to load module 2004-07-27 20:30:56 +00:00
ng_bpf.c Avoid calling bpf_filter() with len == 0, which causes a change in semantics 2004-06-23 02:37:10 +00:00
ng_bpf.h Get rid of the deprecated *LEN constants in favour of the new 2004-01-26 14:05:31 +00:00
ng_bridge.c Convert ipfw to use PFIL_HOOKS. This is change is transparent to userland 2004-08-17 22:05:54 +00:00
ng_bridge.h
ng_cisco.c Switch to using C99 sparse initialisers for the type methods array. 2004-05-29 00:51:19 +00:00
ng_cisco.h
ng_device.c Major overhaul. 2004-10-18 20:13:57 +00:00
ng_device.h Major overhaul. 2004-10-18 20:13:57 +00:00
ng_echo.c Switch to using C99 sparse initialisers for the type methods array. 2004-05-29 00:51:19 +00:00
ng_echo.h
ng_eiface.c Remove orphaned comment about Meta data. 2004-09-11 08:59:06 +00:00
ng_eiface.h Use the (now standard) Ethernet address parse type. 2003-12-17 13:03:32 +00:00
ng_etf.c Having moved metadata usage to mbuf tags, remove code that supports 2004-06-26 22:24:16 +00:00
ng_etf.h Get rid of the deprecated *LEN constants in favour of the new 2004-01-26 14:05:31 +00:00
ng_ether.c Fix packet flow when both ng_ether(4) and bridge(4) are in use: 2004-10-12 10:33:42 +00:00
ng_ether.h Backout previous change, it breaks build and it is not needed 2004-02-20 08:26:27 +00:00
ng_fec.c Avoid casts as lvalues. 2004-07-28 06:59:55 +00:00
ng_fec.h
ng_frame_relay.c Mark 'makeup' in ng_frame_relay as const, as its values are immutable. 2004-07-12 04:35:42 +00:00
ng_frame_relay.h
ng_gif_demux.c Consistently use __inline instead of __inline__ as the former is an empty macro 2004-07-04 16:11:03 +00:00
ng_gif_demux.h
ng_gif.c Avoid casts as lvalues. 2004-07-28 06:59:55 +00:00
ng_gif.h
ng_hole.c Switch to using C99 sparse initialisers for the type methods array. 2004-05-29 00:51:19 +00:00
ng_hole.h Whitespace nit. 2004-05-19 11:35:03 +00:00
ng_hub.c Having moved metadata usage to mbuf tags, remove code that supports 2004-06-26 22:24:16 +00:00
ng_hub.h A simple packet distribution node type that acts like an Ethernet hub. 2004-04-17 12:42:17 +00:00
ng_iface.c Introduce a new mutex, ng_iface_mtx, to protect the global unit list 2004-07-14 20:24:21 +00:00
ng_iface.h Implemented the "getifindex" control message. 2004-03-07 23:00:44 +00:00
ng_ip_input.c Switch to using C99 sparse initialisers for the type methods array. 2004-05-29 00:51:19 +00:00
ng_ip_input.h
ng_ksocket.c In FreeBSD 5.x, curthread is always defined, so we don't need to to test 2004-09-02 19:53:13 +00:00
ng_ksocket.h oops from Gleb.. 2004-06-25 22:59:59 +00:00
ng_l2tp.c Implement minimalistic L2TP sessions statistics and correct man page 2004-08-03 06:52:55 +00:00
ng_l2tp.h Implement minimalistic L2TP sessions statistics and correct man page 2004-08-03 06:52:55 +00:00
ng_lmi.c Convert Netgraph to use mbuf tags to pass its meta information around. 2004-06-25 19:22:05 +00:00
ng_lmi.h
ng_message.h Align netgraph message fields ready for 64-bit (and 128 bit :-) machines. 2004-08-20 01:24:23 +00:00
ng_mppc.c Switch to using C99 sparse initialisers for the type methods array. 2004-05-29 00:51:19 +00:00
ng_mppc.h
ng_one2many.c Having moved metadata usage to mbuf tags, remove code that supports 2004-06-26 22:24:16 +00:00
ng_one2many.h Backout previous change, it breaks build and it is not needed 2004-02-20 08:26:27 +00:00
ng_parse.c Avoid casts as lvalues. 2004-07-28 06:59:55 +00:00
ng_parse.h Get rid of the deprecated *LEN constants in favour of the new 2004-01-26 14:05:31 +00:00
ng_ppp.c Do not change link[n].conf.latency for internal usage but have 2004-08-03 06:34:55 +00:00
ng_ppp.h
ng_pppoe.c Another stupid error from my side. PPPOE_NONSTANDARD was first defined 2004-08-01 20:39:33 +00:00
ng_pppoe.h When node is server serve both standard RFC2516 and non-standard 3Com 2004-07-27 19:47:13 +00:00
ng_pptpgre.c Increase PPTP_MAX_TIMEOUT up to 3 seconds. 10 prooved too much for high packet 2004-09-06 19:53:58 +00:00
ng_pptpgre.h Add 'enableWindowing' configuration knob to the ng_pptpgre(4) netgraph node. 2004-04-26 14:26:54 +00:00
ng_rfc1490.c Make the frameworkl responsible for not passing the nodes a NULL mbuf pointer. 2004-06-25 21:11:14 +00:00
ng_rfc1490.h Add the capacity for the rfc1490 node to handle cisco style encasulation 2004-06-13 15:44:00 +00:00
ng_sample.c Address node in a less complex way. 2004-07-29 08:05:02 +00:00
ng_sample.h
ng_socket.c Acquire Giant arounds calls into the linker from Netgraph sockets. 2004-08-30 14:41:25 +00:00
ng_socket.h
ng_socketvar.h
ng_source.c Slight cosmetic changes. 2004-07-20 17:15:38 +00:00
ng_source.h Define the new command NGM_SOURCE_START_NOW to allow generation of 2004-01-26 14:54:39 +00:00
ng_split.c Switch to using C99 sparse initialisers for the type methods array. 2004-05-29 00:51:19 +00:00
ng_split.h
ng_sppp.c Consistently use __inline instead of __inline__ as the former is an empty macro 2004-07-04 16:11:03 +00:00
ng_sppp.h sppp (4) to netgraph (4) node. As always: I'l connect it to the 2004-03-24 17:24:01 +00:00
ng_tee.c Having moved metadata usage to mbuf tags, remove code that supports 2004-06-26 22:24:16 +00:00
ng_tee.h
ng_tty.c Fix an issue with ng_tty which (ab)used the tty->t_sc field which is 2004-09-17 22:26:27 +00:00
ng_tty.h
ng_UI.c Make the frameworkl responsible for not passing the nodes a NULL mbuf pointer. 2004-06-25 21:11:14 +00:00
ng_UI.h
ng_vjc.c Switch to using C99 sparse initialisers for the type methods array. 2004-05-29 00:51:19 +00:00
ng_vjc.h
ng_vlan.c Switch to using C99 sparse initialisers for the type methods array. 2004-05-29 00:51:19 +00:00
ng_vlan.h Netgraph node type for IEEE 802.1Q VLAN tagging. 2004-03-01 17:22:16 +00:00
NOTES