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Baolin Wang d2da8d3941 usb: gadget: f_fs: Fix possibe deadlock ... commit b3ce3ce02d upstream. When system try to close /dev/usb-ffs/adb/ep0 on one core, at the same time another core try to attach new UDC, which will cause deadlock as below scenario. Thus we should release ffs lock before issuing unregister_gadget_item(). [ 52.642225] c1 ====================================================== [ 52.642228] c1 [ INFO: possible circular locking dependency detected ] [ 52.642236] c1 4.4.6+ #1 Tainted: G W O [ 52.642241] c1 ------------------------------------------------------- [ 52.642245] c1 usb ffs open/2808 is trying to acquire lock: [ 52.642270] c0 (udc_lock){+.+.+.}, at: [<ffffffc00065aeec>] usb_gadget_unregister_driver+0x3c/0xc8 [ 52.642272] c1 but task is already holding lock: [ 52.642283] c0 (ffs_lock){+.+.+.}, at: [<ffffffc00066b244>] ffs_data_clear+0x30/0x140 [ 52.642285] c1 which lock already depends on the new lock. [ 52.642287] c1 the existing dependency chain (in reverse order) is: [ 52.642295] c0 -> #1 (ffs_lock){+.+.+.}: [ 52.642307] c0 [<ffffffc00012340c>] __lock_acquire+0x20f0/0x2238 [ 52.642314] c0 [<ffffffc000123b54>] lock_acquire+0xe4/0x298 [ 52.642322] c0 [<ffffffc000aaf6e8>] mutex_lock_nested+0x7c/0x3cc [ 52.642328] c0 [<ffffffc00066f7bc>] ffs_func_bind+0x504/0x6e8 [ 52.642334] c0 [<ffffffc000654004>] usb_add_function+0x84/0x184 [ 52.642340] c0 [<ffffffc000658ca4>] configfs_composite_bind+0x264/0x39c [ 52.642346] c0 [<ffffffc00065b348>] udc_bind_to_driver+0x58/0x11c [ 52.642352] c0 [<ffffffc00065b49c>] usb_udc_attach_driver+0x90/0xc8 [ 52.642358] c0 [<ffffffc0006598e0>] gadget_dev_desc_UDC_store+0xd4/0x128 [ 52.642369] c0 [<ffffffc0002c14e8>] configfs_write_file+0xd0/0x13c [ 52.642376] c0 [<ffffffc00023c054>] vfs_write+0xb8/0x214 [ 52.642381] c0 [<ffffffc00023cad4>] SyS_write+0x54/0xb0 [ 52.642388] c0 [<ffffffc000085ff0>] el0_svc_naked+0x24/0x28 [ 52.642395] c0 -> #0 (udc_lock){+.+.+.}: [ 52.642401] c0 [<ffffffc00011e3d0>] print_circular_bug+0x84/0x2e4 [ 52.642407] c0 [<ffffffc000123454>] __lock_acquire+0x2138/0x2238 [ 52.642412] c0 [<ffffffc000123b54>] lock_acquire+0xe4/0x298 [ 52.642420] c0 [<ffffffc000aaf6e8>] mutex_lock_nested+0x7c/0x3cc [ 52.642427] c0 [<ffffffc00065aeec>] usb_gadget_unregister_driver+0x3c/0xc8 [ 52.642432] c0 [<ffffffc00065995c>] unregister_gadget_item+0x28/0x44 [ 52.642439] c0 [<ffffffc00066b34c>] ffs_data_clear+0x138/0x140 [ 52.642444] c0 [<ffffffc00066b374>] ffs_data_reset+0x20/0x6c [ 52.642450] c0 [<ffffffc00066efd0>] ffs_data_closed+0xac/0x12c [ 52.642454] c0 [<ffffffc00066f070>] ffs_ep0_release+0x20/0x2c [ 52.642460] c0 [<ffffffc00023dbe4>] __fput+0xb0/0x1f4 [ 52.642466] c0 [<ffffffc00023dd9c>] ____fput+0x20/0x2c [ 52.642473] c0 [<ffffffc0000ee944>] task_work_run+0xb4/0xe8 [ 52.642482] c0 [<ffffffc0000cd45c>] do_exit+0x360/0xb9c [ 52.642487] c0 [<ffffffc0000cf228>] do_group_exit+0x4c/0xb0 [ 52.642494] c0 [<ffffffc0000dd3c8>] get_signal+0x380/0x89c [ 52.642501] c0 [<ffffffc00008a8f0>] do_signal+0x154/0x518 [ 52.642507] c0 [<ffffffc00008af00>] do_notify_resume+0x70/0x78 [ 52.642512] c0 [<ffffffc000085ee8>] work_pending+0x1c/0x20 [ 52.642514] c1 other info that might help us debug this: [ 52.642517] c1 Possible unsafe locking scenario: [ 52.642518] c1 CPU0 CPU1 [ 52.642520] c1 ---- ---- [ 52.642525] c0 lock(ffs_lock); [ 52.642529] c0 lock(udc_lock); [ 52.642533] c0 lock(ffs_lock); [ 52.642537] c0 lock(udc_lock); [ 52.642539] c1 *** DEADLOCK *** [ 52.642543] c1 1 lock held by usb ffs open/2808: [ 52.642555] c0 #0: (ffs_lock){+.+.+.}, at: [<ffffffc00066b244>] ffs_data_clear+0x30/0x140 [ 52.642557] c1 stack backtrace: [ 52.642563] c1 CPU: 1 PID: 2808 Comm: usb ffs open Tainted: G [ 52.642565] c1 Hardware name: Spreadtrum SP9860g Board (DT) [ 52.642568] c1 Call trace: [ 52.642573] c1 [<ffffffc00008b430>] dump_backtrace+0x0/0x170 [ 52.642577] c1 [<ffffffc00008b5c0>] show_stack+0x20/0x28 [ 52.642583] c1 [<ffffffc000422694>] dump_stack+0xa8/0xe0 [ 52.642587] c1 [<ffffffc00011e548>] print_circular_bug+0x1fc/0x2e4 [ 52.642591] c1 [<ffffffc000123454>] __lock_acquire+0x2138/0x2238 [ 52.642595] c1 [<ffffffc000123b54>] lock_acquire+0xe4/0x298 [ 52.642599] c1 [<ffffffc000aaf6e8>] mutex_lock_nested+0x7c/0x3cc [ 52.642604] c1 [<ffffffc00065aeec>] usb_gadget_unregister_driver+0x3c/0xc8 [ 52.642608] c1 [<ffffffc00065995c>] unregister_gadget_item+0x28/0x44 [ 52.642613] c1 [<ffffffc00066b34c>] ffs_data_clear+0x138/0x140 [ 52.642618] c1 [<ffffffc00066b374>] ffs_data_reset+0x20/0x6c [ 52.642621] c1 [<ffffffc00066efd0>] ffs_data_closed+0xac/0x12c [ 52.642625] c1 [<ffffffc00066f070>] ffs_ep0_release+0x20/0x2c [ 52.642629] c1 [<ffffffc00023dbe4>] __fput+0xb0/0x1f4 [ 52.642633] c1 [<ffffffc00023dd9c>] ____fput+0x20/0x2c [ 52.642636] c1 [<ffffffc0000ee944>] task_work_run+0xb4/0xe8 [ 52.642640] c1 [<ffffffc0000cd45c>] do_exit+0x360/0xb9c [ 52.642644] c1 [<ffffffc0000cf228>] do_group_exit+0x4c/0xb0 [ 52.642647] c1 [<ffffffc0000dd3c8>] get_signal+0x380/0x89c [ 52.642651] c1 [<ffffffc00008a8f0>] do_signal+0x154/0x518 [ 52.642656] c1 [<ffffffc00008af00>] do_notify_resume+0x70/0x78 [ 52.642659] c1 [<ffffffc000085ee8>] work_pending+0x1c/0x20 Acked-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Baolin Wang <baolin.wang@linaro.org> Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com> Cc: Jerry Zhang <zhangjerry@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		History 2017-07-05 14:40:18 +02:00
..
function	usb: gadget: f_fs: Fix possibe deadlock	2017-07-05 14:40:18 +02:00
legacy	USB: gadgetfs, dummy-hcd, net2280: fix locking for callbacks	2017-06-24 07:11:16 +02:00
udc	USB: gadgetfs, dummy-hcd, net2280: fix locking for callbacks	2017-06-24 07:11:16 +02:00
composite.c	usb: gadget: composite: Fix function used to free memory	2017-06-24 07:11:17 +02:00
config.c	usb: Use (foo *) instead of (foo*).	2016-06-21 11:16:15 +03:00
configfs.c	usb: gadget: configfs: log function unbinding as debug	2016-08-31 10:06:05 +03:00
configfs.h	usb: gadget: OS descriptors: provide interface directory names	2014-06-19 10:06:48 -05:00
epautoconf.c	usb: gadget: epautoconf: add usb_ep_autoconfig_release() function	2015-09-27 10:54:31 -05:00
functions.c	usb: gadget: add a forward pointer from usb_function to its "instance"	2013-01-21 20:52:46 +02:00
Kconfig	usb: gadget: legacy gadgets are optional	2017-05-20 14:28:35 +02:00
Makefile	usb: gadget: use $(srctree) instead of $(PWD) for includes	2014-08-29 15:53:46 -05:00
u_f.c	usb: gadget: remove useless parameter in alloc_ep_req()	2016-08-25 12:13:19 +03:00
u_f.h	usb: gadget: remove useless parameter in alloc_ep_req()	2016-08-25 12:13:19 +03:00
u_os_desc.h	usb: gadget: u_os_desc: helper functions for accessing ext prop buffer	2014-07-10 08:36:51 -05:00
usbstring.c	usb: delete non-required instances of include <linux/init.h>	2014-01-08 15:01:39 -08:00