Kevin Hao 1413ef638a i2c: dev: Fix the race between the release of i2c_dev and cdev ... The struct cdev is embedded in the struct i2c_dev. In the current code, we would free the i2c_dev struct directly in put_i2c_dev(), but the cdev is manged by a kobject, and the release of it is not predictable. So it is very possible that the i2c_dev is freed before the cdev is entirely released. We can easily get the following call trace with CONFIG_DEBUG_KOBJECT_RELEASE and CONFIG_DEBUG_OBJECTS_TIMERS enabled. ODEBUG: free active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x38 WARNING: CPU: 19 PID: 1 at lib/debugobjects.c:325 debug_print_object+0xb0/0xf0 Modules linked in: CPU: 19 PID: 1 Comm: swapper/0 Tainted: G W 5.2.20-yocto-standard+ #120 Hardware name: Marvell OcteonTX CN96XX board (DT) pstate: 80c00089 (Nzcv daIf +PAN +UAO) pc : debug_print_object+0xb0/0xf0 lr : debug_print_object+0xb0/0xf0 sp : ffff00001292f7d0 x29: ffff00001292f7d0 x28: ffff800b82151788 x27: 0000000000000001 x26: ffff800b892c0000 x25: ffff0000124a2558 x24: 0000000000000000 x23: ffff00001107a1d8 x22: ffff0000116b5088 x21: ffff800bdc6afca8 x20: ffff000012471ae8 x19: ffff00001168f2c8 x18: 0000000000000010 x17: 00000000fd6f304b x16: 00000000ee79de43 x15: ffff800bc0e80568 x14: 79616c6564203a74 x13: 6e6968207473696c x12: 5f72656d6974203a x11: ffff0000113f0018 x10: 0000000000000000 x9 : 000000000000001f x8 : 0000000000000000 x7 : ffff0000101294cc x6 : 0000000000000000 x5 : 0000000000000000 x4 : 0000000000000001 x3 : 00000000ffffffff x2 : 0000000000000000 x1 : 387fc15c8ec0f200 x0 : 0000000000000000 Call trace: debug_print_object+0xb0/0xf0 __debug_check_no_obj_freed+0x19c/0x228 debug_check_no_obj_freed+0x1c/0x28 kfree+0x250/0x440 put_i2c_dev+0x68/0x78 i2cdev_detach_adapter+0x60/0xc8 i2cdev_notifier_call+0x3c/0x70 notifier_call_chain+0x8c/0xe8 blocking_notifier_call_chain+0x64/0x88 device_del+0x74/0x380 device_unregister+0x54/0x78 i2c_del_adapter+0x278/0x2d0 unittest_i2c_bus_remove+0x3c/0x80 platform_drv_remove+0x30/0x50 device_release_driver_internal+0xf4/0x1c0 driver_detach+0x58/0xa0 bus_remove_driver+0x84/0xd8 driver_unregister+0x34/0x60 platform_driver_unregister+0x20/0x30 of_unittest_overlay+0x8d4/0xbe0 of_unittest+0xae8/0xb3c do_one_initcall+0xac/0x450 do_initcall_level+0x208/0x224 kernel_init_freeable+0x2d8/0x36c kernel_init+0x18/0x108 ret_from_fork+0x10/0x1c irq event stamp: 3934661 hardirqs last enabled at (3934661): [<ffff00001009fa04>] debug_exception_exit+0x4c/0x58 hardirqs last disabled at (3934660): [<ffff00001009fb14>] debug_exception_enter+0xa4/0xe0 softirqs last enabled at (3934654): [<ffff000010081d94>] __do_softirq+0x46c/0x628 softirqs last disabled at (3934649): [<ffff0000100b4a1c>] irq_exit+0x104/0x118 This is a common issue when using cdev embedded in a struct. Fortunately, we already have a mechanism to solve this kind of issue. Please see commit 233ed09d7f ("chardev: add helper function to register char devs with a struct device") for more detail. In this patch, we choose to embed the struct device into the i2c_dev, and use the API provided by the commit 233ed09d7f to make sure that the release of i2c_dev and cdev are in sequence. Signed-off-by: Kevin Hao <haokexin@gmail.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>		2020-03-20 18:34:29 +01:00
..
algos	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157	2019-05-30 11:26:37 -07:00
busses	i2c: qcom-geni: Drop of_platform.h include	2020-03-13 15:20:39 +01:00
muxes	i2c: mux: pca954x: support property idle-state	2020-01-03 15:00:53 +01:00
i2c-boardinfo.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157	2019-05-30 11:26:37 -07:00
i2c-core-acpi.c	i2c: i2c-core-acpi: convert to use i2c_new_client_device()	2020-01-15 20:39:55 +01:00
i2c-core-base.c	i2c: i2c-core-base: convert to use i2c_new_client_device()	2020-01-15 20:40:08 +01:00
i2c-core-of.c	i2c: i2c-core-of: convert to use i2c_new_client_device()	2020-01-15 20:40:12 +01:00
i2c-core-slave.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152	2019-05-30 11:26:32 -07:00
i2c-core-smbus.c	i2c: smbus: remove outdated references to irq level triggers	2020-03-10 12:20:04 +01:00
i2c-core.h	Merge branch 'i2c/for-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux	2019-07-15 21:10:39 -07:00
i2c-dev.c	i2c: dev: Fix the race between the release of i2c_dev and cdev	2020-03-20 18:34:29 +01:00
i2c-mux.c	i2c: mux: add sysfs header	2019-06-22 07:32:33 +02:00
i2c-slave-eeprom.c	i2c: use kobj_to_dev() API	2020-03-10 10:50:08 +01:00
i2c-smbus.c	i2c: convert SMBus alert setup function to return an ERRPTR	2020-03-10 12:19:52 +01:00
i2c-stub.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157	2019-05-30 11:26:37 -07:00
Kconfig	docs: i2c: convert to ReST and add to driver-api bookset	2019-07-31 13:25:27 -06:00
Makefile	i2c: don't use any __deprecated handling anymore	2018-08-24 17:26:43 +02:00