config USBIP_CORE tristate "USB/IP support" depends on NET select USB_COMMON ---help--- This enables pushing USB packets over IP to allow remote machines direct access to USB devices. It provides the USB/IP core that is required by both drivers. For more details, and to get the userspace utility programs, please see . To compile this as a module, choose M here: the module will be called usbip-core. If unsure, say N. config USBIP_VHCI_HCD tristate "VHCI hcd" depends on USBIP_CORE && USB ---help--- This enables the USB/IP virtual host controller driver, which is run on the remote machine. To compile this driver as a module, choose M here: the module will be called vhci-hcd. config USBIP_VHCI_HC_PORTS int "Number of ports per USB/IP virtual host controller" range 1 31 default 8 depends on USBIP_VHCI_HCD ---help--- To increase number of ports available for USB/IP virtual host controller driver, this defines number of ports per USB/IP virtual host controller. config USBIP_VHCI_NR_HCS int "Number of USB/IP virtual host controllers" range 1 128 default 1 depends on USBIP_VHCI_HCD ---help--- To increase number of ports available for USB/IP virtual host controller driver, this defines number of USB/IP virtual host controllers as if adding physical host controllers. config USBIP_HOST tristate "Host driver" depends on USBIP_CORE && USB ---help--- This enables the USB/IP host driver, which is run on the machine that is sharing the USB devices. To compile this driver as a module, choose M here: the module will be called usbip-host. config USBIP_VUDC tristate "VUDC driver" depends on USBIP_CORE && USB_GADGET ---help--- This enables the USB/IP virtual USB device controller driver, which is run on the host machine, allowing the machine itself to act as a device. To compile this driver as a module, choose M here: the module will be called usbip-vudc. config USBIP_DEBUG bool "Debug messages for USB/IP" depends on USBIP_CORE ---help--- This enables the debug messages from the USB/IP drivers. ef='/cgit.cgi/linux/net-next.git/diff/sound/soc/soc-jack.c?h=nds-private-remove&id=966d2b04e070bc040319aaebfec09e0144dc3341'>diff
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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 /sound/soc/soc-jack.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 'sound/soc/soc-jack.c')