#ifndef LLC_CONN_H #define LLC_CONN_H /* * Copyright (c) 1997 by Procom Technology, Inc. * 2001, 2002 by Arnaldo Carvalho de Melo * * This program can be redistributed or modified under the terms of the * GNU General Public License as published by the Free Software Foundation. * This program is distributed without any warranty or implied warranty * of merchantability or fitness for a particular purpose. * * See the GNU General Public License for more details. */ #include #include #include #include #define LLC_EVENT 1 #define LLC_PACKET 2 #define LLC2_P_TIME 2 #define LLC2_ACK_TIME 1 #define LLC2_REJ_TIME 3 #define LLC2_BUSY_TIME 3 struct llc_timer { struct timer_list timer; unsigned long expire; /* timer expire time */ }; struct llc_sock { /* struct sock must be the first member of llc_sock */ struct sock sk; struct sockaddr_llc addr; /* address sock is bound to */ u8 state; /* state of connection */ struct llc_sap *sap; /* pointer to parent SAP */ struct llc_addr laddr; /* lsap/mac pair */ struct llc_addr daddr; /* dsap/mac pair */ struct net_device *dev; /* device to send to remote */ u32 copied_seq; /* head of yet unread data */ u8 retry_count; /* number of retries */ u8 ack_must_be_send; u8 first_pdu_Ns; u8 npta; struct llc_timer ack_timer; struct llc_timer pf_cycle_timer; struct llc_timer rej_sent_timer; struct llc_timer busy_state_timer; /* ind busy clr at remote LLC */ u8 vS; /* seq# next in-seq I-PDU tx'd*/ u8 vR; /* seq# next in-seq I-PDU rx'd*/ u32 n2; /* max nbr re-tx's for timeout*/ u32 n1; /* max nbr octets in I PDU */ u8 k; /* tx window size; max = 127 */ u8 rw; /* rx window size; max = 127 */ u8 p_flag; /* state flags */ u8 f_flag; u8 s_flag; u8 data_flag; u8 remote_busy_flag; u8 cause_flag; struct sk_buff_head pdu_unack_q; /* PUDs sent/waiting ack */ u16 link; /* network layer link number */ u8 X; /* a temporary variable */ u8 ack_pf; /* this flag indicates what is the P-bit of acknowledge */ u8 failed_data_req; /* recognize that already exist a failed llc_data_req_handler (tx_buffer_full or unacceptable state */ u8 dec_step; u8 inc_cntr; u8 dec_cntr; u8 connect_step; u8 last_nr; /* NR of last pdu received */ u32 rx_pdu_hdr; /* used for saving header of last pdu received and caused sending FRMR. Used for resending FRMR */ u32 cmsg_flags; struct hlist_node dev_hash_node; }; static inline struct llc_sock *llc_sk(const struct sock *sk) { return (struct llc_sock *)sk; } static __inline__ void llc_set_backlog_type(struct sk_buff *skb, char type) { skb->cb[sizeof(skb->cb) - 1] = type; } static __inline__ char llc_backlog_type(struct sk_buff *skb) { return skb->cb[sizeof(skb->cb) - 1]; } struct sock *llc_sk_alloc(struct net *net, int family, gfp_t priority, struct proto *prot, int kern); void llc_sk_free(struct sock *sk); void llc_sk_reset(struct sock *sk); /* Access to a connection */ int llc_conn_state_process(struct sock *sk, struct sk_buff *skb); void llc_conn_send_pdu(struct sock *sk, struct sk_buff *skb); void llc_conn_rtn_pdu(struct sock *sk, struct sk_buff *skb); void llc_conn_resend_i_pdu_as_cmd(struct sock *sk, u8 nr, u8 first_p_bit); void llc_conn_resend_i_pdu_as_rsp(struct sock *sk, u8 nr, u8 first_f_bit); int llc_conn_remove_acked_pdus(struct sock *conn, u8 nr, u16 *how_many_unacked); struct sock *llc_lookup_established(struct llc_sap *sap, struct llc_addr *daddr, struct llc_addr *laddr); void llc_sap_add_socket(struct llc_sap *sap, struct sock *sk); void llc_sap_remove_socket(struct llc_sap *sap, struct sock *sk); u8 llc_data_accept_state(u8 state); void llc_build_offset_table(void); #endif /* LLC_CONN_H */ space:mode:
authorDouglas Miller <dougmill@linux.vnet.ibm.com>2017-01-28 06:42:20 -0600
committerTejun Heo <tj@kernel.org>2017-01-28 07:49:42 -0500
commit966d2b04e070bc040319aaebfec09e0144dc3341 (patch)
tree4b96156e3d1dd4dfd6039b7c219c9dc4616da52d /net/mac80211
parent1b1bc42c1692e9b62756323c675a44cb1a1f9dbd (diff)
percpu-refcount: fix reference leak during percpu-atomic transition
percpu_ref_tryget() and percpu_ref_tryget_live() should return "true" IFF they acquire a reference. But the return value from atomic_long_inc_not_zero() is a long and may have high bits set, e.g. PERCPU_COUNT_BIAS, and the return value of the tryget routines is bool so the reference may actually be acquired but the routines return "false" which results in a reference leak since the caller assumes it does not need to do a corresponding percpu_ref_put(). This was seen when performing CPU hotplug during I/O, as hangs in blk_mq_freeze_queue_wait where percpu_ref_kill (blk_mq_freeze_queue_start) raced with percpu_ref_tryget (blk_mq_timeout_work). Sample stack trace: __switch_to+0x2c0/0x450 __schedule+0x2f8/0x970 schedule+0x48/0xc0 blk_mq_freeze_queue_wait+0x94/0x120 blk_mq_queue_reinit_work+0xb8/0x180 blk_mq_queue_reinit_prepare+0x84/0xa0 cpuhp_invoke_callback+0x17c/0x600 cpuhp_up_callbacks+0x58/0x150 _cpu_up+0xf0/0x1c0 do_cpu_up+0x120/0x150 cpu_subsys_online+0x64/0xe0 device_online+0xb4/0x120 online_store+0xb4/0xc0 dev_attr_store+0x68/0xa0 sysfs_kf_write+0x80/0xb0 kernfs_fop_write+0x17c/0x250 __vfs_write+0x6c/0x1e0 vfs_write+0xd0/0x270 SyS_write+0x6c/0x110 system_call+0x38/0xe0 Examination of the queue showed a single reference (no PERCPU_COUNT_BIAS, and __PERCPU_REF_DEAD, __PERCPU_REF_ATOMIC set) and no requests. However, conditions at the time of the race are count of PERCPU_COUNT_BIAS + 0 and __PERCPU_REF_DEAD and __PERCPU_REF_ATOMIC set. The fix is to make the tryget routines use an actual boolean internally instead of the atomic long result truncated to a int. Fixes: e625305b3907 percpu-refcount: make percpu_ref based on longs instead of ints Link: https://bugzilla.kernel.org/show_bug.cgi?id=190751 Signed-off-by: Douglas Miller <dougmill@linux.vnet.ibm.com> Reviewed-by: Jens Axboe <axboe@fb.com> Signed-off-by: Tejun Heo <tj@kernel.org> Fixes: e625305b3907 ("percpu-refcount: make percpu_ref based on longs instead of ints") Cc: stable@vger.kernel.org # v3.18+
Diffstat (limited to 'net/mac80211')