/****************************************************************************** * usbatm.h - Generic USB xDSL driver core * * Copyright (C) 2001, Alcatel * Copyright (C) 2003, Duncan Sands, SolNegro, Josep Comas * Copyright (C) 2004, David Woodhouse * * 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, write to the Free Software Foundation, Inc., 59 * Temple Place - Suite 330, Boston, MA 02111-1307, USA. * ******************************************************************************/ #ifndef _USBATM_H_ #define _USBATM_H_ #include #include #include #include #include #include #include #include #include #include #include /* #define VERBOSE_DEBUG */ #define usb_err(instance, format, arg...) \ dev_err(&(instance)->usb_intf->dev , format , ## arg) #define usb_info(instance, format, arg...) \ dev_info(&(instance)->usb_intf->dev , format , ## arg) #define usb_warn(instance, format, arg...) \ dev_warn(&(instance)->usb_intf->dev , format , ## arg) #define usb_dbg(instance, format, arg...) \ dev_dbg(&(instance)->usb_intf->dev , format , ## arg) /* FIXME: move to dev_* once ATM is driver model aware */ #define atm_printk(level, instance, format, arg...) \ printk(level "ATM dev %d: " format , \ (instance)->atm_dev->number , ## arg) #define atm_err(instance, format, arg...) \ atm_printk(KERN_ERR, instance , format , ## arg) #define atm_info(instance, format, arg...) \ atm_printk(KERN_INFO, instance , format , ## arg) #define atm_warn(instance, format, arg...) \ atm_printk(KERN_WARNING, instance , format , ## arg) #define atm_dbg(instance, format, ...) \ pr_debug("ATM dev %d: " format, \ (instance)->atm_dev->number, ##__VA_ARGS__) #define atm_rldbg(instance, format, ...) \ pr_debug_ratelimited("ATM dev %d: " format, \ (instance)->atm_dev->number, ##__VA_ARGS__) /* flags, set by mini-driver in bind() */ #define UDSL_SKIP_HEAVY_INIT (1<<0) #define UDSL_USE_ISOC (1<<1) #define UDSL_IGNORE_EILSEQ (1<<2) /* mini driver */ struct usbatm_data; /* * Assuming all methods exist and succeed, they are called in this order: * * bind, heavy_init, atm_start, ..., atm_stop, unbind */ struct usbatm_driver { const char *driver_name; /* init device ... can sleep, or cause probe() failure */ int (*bind) (struct usbatm_data *, struct usb_interface *, const struct usb_device_id *id); /* additional device initialization that is too slow to be done in probe() */ int (*heavy_init) (struct usbatm_data *, struct usb_interface *); /* cleanup device ... can sleep, but can't fail */ void (*unbind) (struct usbatm_data *, struct usb_interface *); /* init ATM device ... can sleep, or cause ATM initialization failure */ int (*atm_start) (struct usbatm_data *, struct atm_dev *); /* cleanup ATM device ... can sleep, but can't fail */ void (*atm_stop) (struct usbatm_data *, struct atm_dev *); int bulk_in; /* bulk rx endpoint */ int isoc_in; /* isochronous rx endpoint */ int bulk_out; /* bulk tx endpoint */ unsigned rx_padding; unsigned tx_padding; }; extern int usbatm_usb_probe(struct usb_interface *intf, const struct usb_device_id *id, struct usbatm_driver *driver); extern void usbatm_usb_disconnect(struct usb_interface *intf); struct usbatm_channel { int endpoint; /* usb pipe */ unsigned int stride; /* ATM cell size + padding */ unsigned int buf_size; /* urb buffer size */ unsigned int packet_size; /* endpoint maxpacket */ spinlock_t lock; struct list_head list; struct tasklet_struct tasklet; struct timer_list delay; struct usbatm_data *usbatm; }; /* main driver data */ struct usbatm_data { /****************** * public fields * ******************/ /* mini driver */ struct usbatm_driver *driver; void *driver_data; char driver_name[16]; unsigned int flags; /* set by mini-driver in bind() */ /* USB device */ struct usb_device *usb_dev; struct usb_interface *usb_intf; char description[64]; /* ATM device */ struct atm_dev *atm_dev; /******************************** * private fields - do not use * ********************************/ struct kref refcount; struct mutex serialize; int disconnected; /* heavy init */ struct task_struct *thread; struct completion thread_started; struct completion thread_exited; /* ATM device */ struct list_head vcc_list; struct usbatm_channel rx_channel; struct usbatm_channel tx_channel; struct sk_buff_head sndqueue; struct sk_buff *current_skb; /* being emptied */ struct usbatm_vcc_data *cached_vcc; int cached_vci; short cached_vpi; unsigned char *cell_buf; /* holds partial rx cell */ unsigned int buf_usage; struct urb *urbs[0]; }; static inline void *to_usbatm_driver_data(struct usb_interface *intf) { struct usbatm_data *usbatm_instance; if (intf == NULL) return NULL; usbatm_instance = usb_get_intfdata(intf); if (usbatm_instance == NULL) /* set NULL before unbind() */ return NULL; return usbatm_instance->driver_data; /* set NULL after unbind() */ } #endif /* _USBATM_H_ */ unction/f_obex.c?id=966d2b04e070bc040319aaebfec09e0144dc3341'>drivers/usb/gadget/function/f_obex.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 'drivers/usb/gadget/function/f_obex.c')