On Tue, Nov 02, 2021 at 04:51:51PM -0700, Sujit Kautkar wrote: > Replace cdev add/del APIs with cdev_device_add/cdev_device_del to avoid > below kernel warning. This correctly takes a reference to the parent > device so the parent will not get released until all references to the > cdev are released. > > | ODEBUG: free active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x7c > | WARNING: CPU: 7 PID: 19892 at lib/debugobjects.c:488 debug_print_object+0x13c/0x1b0 > | CPU: 7 PID: 19892 Comm: kworker/7:4 Tainted: G W 5.4.147-lockdep #1 > | ================================================================== > | Hardware name: Google CoachZ (rev1 - 2) with LTE (DT) > | Workqueue: events kobject_delayed_cleanup > | pstate: 60c00009 (nZCv daif +PAN +UAO) > | pc : debug_print_object+0x13c/0x1b0 > | lr : debug_print_object+0x13c/0x1b0 > | sp : ffffff83b2ec7970 > | x29: ffffff83b2ec7970 x28: dfffffd000000000 > | x27: ffffff83d674f000 x26: dfffffd000000000 > | x25: ffffffd06b8fa660 x24: dfffffd000000000 > | x23: 0000000000000000 x22: ffffffd06b7c5108 > | x21: ffffffd06d597860 x20: ffffffd06e2c21c0 > | x19: ffffffd06d5974c0 x18: 000000000001dad8 > | x17: 0000000000000000 x16: dfffffd000000000 > | BUG: KASAN: use-after-free in qcom_glink_rpdev_release+0x54/0x70 > | x15: ffffffffffffffff x14: 79616c6564203a74 > | x13: 0000000000000000 x12: 0000000000000080 > | Write of size 8 at addr ffffff83d95768d0 by task kworker/3:1/150 > | x11: 0000000000000001 x10: 0000000000000000 > | x9 : fc9e8edec0ad0300 x8 : fc9e8edec0ad0300 > | > | x7 : 0000000000000000 x6 : 0000000000000000 > | x5 : 0000000000000080 x4 : 0000000000000000 > | CPU: 3 PID: 150 Comm: kworker/3:1 Tainted: G W 5.4.147-lockdep #1 > | x3 : ffffffd06c149574 x2 : ffffff83f77f7498 > | x1 : ffffffd06d596f60 x0 : 0000000000000061 > | Hardware name: Google CoachZ (rev1 - 2) with LTE (DT) > | Call trace: > | debug_print_object+0x13c/0x1b0 > | Workqueue: events kobject_delayed_cleanup > | __debug_check_no_obj_freed+0x25c/0x3c0 > | debug_check_no_obj_freed+0x18/0x20 > | Call trace: > | slab_free_freelist_hook+0xb4/0x1bc > | kfree+0xe8/0x2d8 > | dump_backtrace+0x0/0x27c > | rpmsg_ctrldev_release_device+0x78/0xb8 > | device_release+0x68/0x14c > | show_stack+0x20/0x2c > | kobject_cleanup+0x12c/0x298 > | kobject_delayed_cleanup+0x10/0x18 > | dump_stack+0xe0/0x19c > | process_one_work+0x578/0x92c > | worker_thread+0x804/0xcf8 > | print_address_description+0x3c/0x4a8 > | kthread+0x2a8/0x314 > | ret_from_fork+0x10/0x18 > | __kasan_report+0x100/0x124 > > Signed-off-by: Sujit Kautkar <sujitka@xxxxxxxxxxxx> Reviewed-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx>
