/********************************************************************* * * Filename: irlap_frame.h * Version: 0.9 * Description: IrLAP frame declarations * Status: Experimental. * Author: Dag Brattli * Created at: Tue Aug 19 10:27:26 1997 * Modified at: Sat Dec 25 21:07:26 1999 * Modified by: Dag Brattli * * Copyright (c) 1997-1999 Dag Brattli , * All Rights Reserved. * Copyright (c) 2000-2002 Jean Tourrilhes * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation; either version 2 of * the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, see . * ********************************************************************/ #ifndef IRLAP_FRAME_H #define IRLAP_FRAME_H #include #include /* A few forward declarations (to make compiler happy) */ struct irlap_cb; struct discovery_t; /* Frame types and templates */ #define INVALID 0xff /* Unnumbered (U) commands */ #define SNRM_CMD 0x83 /* Set Normal Response Mode */ #define DISC_CMD 0x43 /* Disconnect */ #define XID_CMD 0x2f /* Exchange Station Identification */ #define TEST_CMD 0xe3 /* Test */ /* Unnumbered responses */ #define RNRM_RSP 0x83 /* Request Normal Response Mode */ #define UA_RSP 0x63 /* Unnumbered Acknowledgement */ #define FRMR_RSP 0x87 /* Frame Reject */ #define DM_RSP 0x0f /* Disconnect Mode */ #define RD_RSP 0x43 /* Request Disconnection */ #define XID_RSP 0xaf /* Exchange Station Identification */ #define TEST_RSP 0xe3 /* Test frame */ /* Supervisory (S) */ #define RR 0x01 /* Receive Ready */ #define REJ 0x09 /* Reject */ #define RNR 0x05 /* Receive Not Ready */ #define SREJ 0x0d /* Selective Reject */ /* Information (I) */ #define I_FRAME 0x00 /* Information Format */ #define UI_FRAME 0x03 /* Unnumbered Information */ #define CMD_FRAME 0x01 #define RSP_FRAME 0x00 #define PF_BIT 0x10 /* Poll/final bit */ /* Some IrLAP field lengths */ /* * Only baud rate triplet is 4 bytes (PV can be 2 bytes). * All others params (7) are 3 bytes, so that's 7*3 + 1*4 bytes. */ #define IRLAP_NEGOCIATION_PARAMS_LEN 25 #define IRLAP_DISCOVERY_INFO_LEN 32 struct disc_frame { __u8 caddr; /* Connection address */ __u8 control; } __packed; struct xid_frame { __u8 caddr; /* Connection address */ __u8 control; __u8 ident; /* Should always be XID_FORMAT */ __le32 saddr; /* Source device address */ __le32 daddr; /* Destination device address */ __u8 flags; /* Discovery flags */ __u8 slotnr; __u8 version; } __packed; struct test_frame { __u8 caddr; /* Connection address */ __u8 control; __le32 saddr; /* Source device address */ __le32 daddr; /* Destination device address */ } __packed; struct ua_frame { __u8 caddr; __u8 control; __le32 saddr; /* Source device address */ __le32 daddr; /* Dest device address */ } __packed; struct dm_frame { __u8 caddr; /* Connection address */ __u8 control; } __packed; struct rd_frame { __u8 caddr; /* Connection address */ __u8 control; } __packed; struct rr_frame { __u8 caddr; /* Connection address */ __u8 control; } __packed; struct i_frame { __u8 caddr; __u8 control; } __packed; struct snrm_frame { __u8 caddr; __u8 control; __le32 saddr; __le32 daddr; __u8 ncaddr; } __packed; void irlap_queue_xmit(struct irlap_cb *self, struct sk_buff *skb); void irlap_send_discovery_xid_frame(struct irlap_cb *, int S, __u8 s, __u8 command, struct discovery_t *discovery); void irlap_send_snrm_frame(struct irlap_cb *, struct qos_info *); void irlap_send_test_frame(struct irlap_cb *self, __u8 caddr, __u32 daddr, struct sk_buff *cmd); void irlap_send_ua_response_frame(struct irlap_cb *, struct qos_info *); void irlap_send_dm_frame(struct irlap_cb *self); void irlap_send_rd_frame(struct irlap_cb *self); void irlap_send_disc_frame(struct irlap_cb *self); void irlap_send_rr_frame(struct irlap_cb *self, int command); void irlap_send_data_primary(struct irlap_cb *, struct sk_buff *); void irlap_send_data_primary_poll(struct irlap_cb *, struct sk_buff *); void irlap_send_data_secondary(struct irlap_cb *, struct sk_buff *); void irlap_send_data_secondary_final(struct irlap_cb *, struct sk_buff *); void irlap_resend_rejected_frames(struct irlap_cb *, int command); void irlap_resend_rejected_frame(struct irlap_cb *self, int command); void irlap_send_ui_frame(struct irlap_cb *self, struct sk_buff *skb, __u8 caddr, int command); int irlap_insert_qos_negotiation_params(struct irlap_cb *self, struct sk_buff *skb); #endif a href='/cgit.cgi/linux/net-next.git/tree/net/ipv6/af_inet6.c?id=966d2b04e070bc040319aaebfec09e0144dc3341'>net/ipv6/af_inet6.c 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/ipv6/af_inet6.c')