/********************************************************************* * * Filename: irqueue.h * Version: 0.3 * Description: General queue implementation * Status: Experimental. * Author: Dag Brattli * Created at: Tue Jun 9 13:26:50 1998 * Modified at: Thu Oct 7 13:25:16 1999 * Modified by: Dag Brattli * * Copyright (C) 1998-1999, Aage Kvalnes * Copyright (c) 1998, Dag Brattli * All Rights Reserved. * * This code is taken from the Vortex Operating System written by Aage * Kvalnes and has been ported to Linux and Linux/IR by Dag Brattli * * 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. * * Neither Dag Brattli nor University of Tromsø admit liability nor * provide warranty for any of this software. This material is * provided "AS-IS" and at no charge. * ********************************************************************/ #include #include #ifndef IRDA_QUEUE_H #define IRDA_QUEUE_H #define NAME_SIZE 32 /* * Hash types (some flags can be xored) * See comments in irqueue.c for which one to use... */ #define HB_NOLOCK 0 /* No concurent access prevention */ #define HB_LOCK 1 /* Prevent concurent write with global lock */ /* * Hash defines */ #define HASHBIN_SIZE 8 #define HASHBIN_MASK 0x7 #ifndef IRDA_ALIGN #define IRDA_ALIGN __attribute__((aligned)) #endif #define Q_NULL { NULL, NULL, "", 0 } typedef void (*FREE_FUNC)(void *arg); struct irda_queue { struct irda_queue *q_next; struct irda_queue *q_prev; char q_name[NAME_SIZE]; long q_hash; /* Must be able to cast a (void *) */ }; typedef struct irda_queue irda_queue_t; typedef struct hashbin_t { __u32 magic; int hb_type; int hb_size; spinlock_t hb_spinlock; /* HB_LOCK - Can be used by the user */ irda_queue_t* hb_queue[HASHBIN_SIZE] IRDA_ALIGN; irda_queue_t* hb_current; } hashbin_t; hashbin_t *hashbin_new(int type); int hashbin_delete(hashbin_t* hashbin, FREE_FUNC func); int hashbin_clear(hashbin_t* hashbin, FREE_FUNC free_func); void hashbin_insert(hashbin_t* hashbin, irda_queue_t* entry, long hashv, const char* name); void* hashbin_remove(hashbin_t* hashbin, long hashv, const char* name); void* hashbin_remove_first(hashbin_t *hashbin); void* hashbin_remove_this( hashbin_t* hashbin, irda_queue_t* entry); void* hashbin_find(hashbin_t* hashbin, long hashv, const char* name); void* hashbin_lock_find(hashbin_t* hashbin, long hashv, const char* name); void* hashbin_find_next(hashbin_t* hashbin, long hashv, const char* name, void ** pnext); irda_queue_t *hashbin_get_first(hashbin_t *hashbin); irda_queue_t *hashbin_get_next(hashbin_t *hashbin); #define HASHBIN_GET_SIZE(hashbin) hashbin->hb_size #endif move&id=966d2b04e070bc040319aaebfec09e0144dc3341'>drivers/usb/dwc2/hcd.h
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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 /drivers/usb/dwc2/hcd.h
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 'drivers/usb/dwc2/hcd.h')