On Tue, 24 Oct, 2023 17:49:36 +0800 "be286" <be286@xxxxxxx> wrote: > Hi Rahul, > > > When hid_debug_events_release() was being called, in most case, > hid_device_release() finish already, the memory of list->hdev > freed by hid_device_release(), if list->hdev memory > reallocate by others, and it's modified, zeroed, then > list->hdev->debug_list_lock occasioned crash come out. > This makes sense to me. Thanks for the additional explanation. I would add this detail to the commit message body of your v2 to make the patch clearer. With this explanation, I think your patch makes a lot of sense to me and I understand better why you are seeing the trace you shared. > The runing order: > > [ 258.201069] CPU: 0 PID: 203 Comm: kworker/0:2 Not tainted 5.10.110 #255 > [ 258.201073] Hardware name: Rockchip RK3588 EVB4 LP4 V10 Board (DT) > [ 258.201086] Workqueue: usb_hub_wq hub_event > [ 258.201092] Call trace: > [ 258.201100] dump_backtrace+0x0/0x1f8 > [ 258.201105] show_stack+0x1c/0x2c > [ 258.201112] dump_stack_lvl+0xd8/0x12c > [ 258.201116] dump_stack+0x1c/0x60 > [ 258.201122] hid_device_release+0x94/0xb4 > [ 258.201127] device_release+0x38/0x94 > [ 258.201133] kobject_cleanup+0xd0/0x174 > [ 258.201137] kobject_put+0x68/0xa8 > [ 258.201143] put_device+0x1c/0x2c > [ 258.201146] hid_destroy_device+0x60/0x74 > [ 258.201153] usbhid_disconnect+0x5c/0x90 > [ 258.201157] usb_unbind_interface+0xc4/0x268 > [ 258.201162] device_release_driver_internal+0x184/0x25c > [ 258.201165] device_release_driver+0x1c/0x2c > [ 258.201169] bus_remove_device+0xdc/0x138 > [ 258.201173] device_del+0x1d0/0x3d8 > [ 258.201177] usb_disable_device+0x108/0x228 > [ 258.201181] usb_disconnect+0xf4/0x304 > [ 258.201184] usb_disconnect+0xdc/0x304 > [ 258.201188] hub_port_connect+0x88/0xa24 > [ 258.201191] hub_port_connect_change+0x2d8/0x4cc > [ 258.201195] port_event+0x550/0x614 > [ 258.201198] hub_event+0x12c/0x494 > [ 258.201203] process_one_work+0x1f4/0x490 > [ 258.201207] worker_thread+0x278/0x4dc > [ 258.201211] kthread+0x130/0x338 > [ 258.201215] ret_from_fork+0x10/0x30 > [ 259.925641] CPU: 1 PID: 2354 Comm: hidt_bridge Not tainted 5.10.110 #255 > [ 259.925652] Hardware name: Rockchip RK3588 EVB4 LP4 V10 Board (DT) > [ 259.925656] Call trace: > [ 259.925671] dump_backtrace+0x0/0x1f8 > [ 259.925676] show_stack+0x1c/0x2c > [ 259.925685] dump_stack_lvl+0xd8/0x12c > [ 259.925689] dump_stack+0x1c/0x60 > [ 259.925697] hid_debug_events_release+0x24/0x134 > [ 259.925704] full_proxy_release+0x50/0xbc > [ 259.925709] __fput+0xdc/0x238 > [ 259.925714] ____fput+0x14/0x24 > [ 259.925720] task_work_run+0x90/0x148 > [ 259.925725] do_exit+0x1bc/0x8a4 > [ 259.925729] do_group_exit+0x8c/0xa4 > [ 259.925734] get_signal+0x468/0x744 > [ 259.925739] do_signal+0x84/0x280 > [ 259.925743] do_notify_resume+0xd8/0x228 > [ 259.925747] work_pending+0xc/0x3f0 > > The crash: > > [ 120.728477][ T4396] kernel BUG at lib/list_debug.c:53! > [ 120.728505][ T4396] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP > [ 120.739806][ T4396] Modules linked in: bcmdhd dhd_static_buf 8822cu pcie_mhi r8168 > [ 120.747386][ T4396] CPU: 1 PID: 4396 Comm: hidt_bridge Not tainted 5.10.110 #257 > [ 120.754771][ T4396] Hardware name: Rockchip RK3588 EVB4 LP4 V10 Board (DT) > [ 120.761643][ T4396] pstate: 60400089 (nZCv daIf +PAN -UAO -TCO BTYPE=--) > [ 120.768338][ T4396] pc : __list_del_entry_valid+0x98/0xac > [ 120.773730][ T4396] lr : __list_del_entry_valid+0x98/0xac > [ 120.779120][ T4396] sp : ffffffc01e62bb60 > [ 120.783126][ T4396] x29: ffffffc01e62bb60 x28: ffffff818ce3a200 > [ 120.789126][ T4396] x27: 0000000000000009 x26: 0000000000980000 > [ 120.795126][ T4396] x25: ffffffc012431000 x24: ffffff802c6d4e00 > [ 120.801125][ T4396] x23: ffffff8005c66f00 x22: ffffffc01183b5b8 > [ 120.807125][ T4396] x21: ffffff819df2f100 x20: 0000000000000000 > [ 120.813124][ T4396] x19: ffffff802c3f0700 x18: ffffffc01d2cd058 > [ 120.819124][ T4396] x17: 0000000000000000 x16: 0000000000000000 > [ 120.825124][ T4396] x15: 0000000000000004 x14: 0000000000003fff > [ 120.831123][ T4396] x13: ffffffc012085588 x12: 0000000000000003 > [ 120.837123][ T4396] x11: 00000000ffffbfff x10: 0000000000000003 > [ 120.843123][ T4396] x9 : 455103d46b329300 x8 : 455103d46b329300 > [ 120.849124][ T4396] x7 : 74707572726f6320 x6 : ffffffc0124b8cb5 > [ 120.855124][ T4396] x5 : ffffffffffffffff x4 : 0000000000000000 > [ 120.861123][ T4396] x3 : ffffffc011cf4f90 x2 : ffffff81fee7b948 > [ 120.867122][ T4396] x1 : ffffffc011cf4f90 x0 : 0000000000000054 > [ 120.873122][ T4396] Call trace: > [ 120.876259][ T4396] __list_del_entry_valid+0x98/0xac > [ 120.881304][ T4396] hid_debug_events_release+0x48/0x12c > [ 120.886617][ T4396] full_proxy_release+0x50/0xbc > [ 120.891323][ T4396] __fput+0xdc/0x238 > [ 120.895075][ T4396] ____fput+0x14/0x24 > [ 120.898911][ T4396] task_work_run+0x90/0x148 > [ 120.903268][ T4396] do_exit+0x1bc/0x8a4 > [ 120.907193][ T4396] do_group_exit+0x8c/0xa4 > [ 120.911458][ T4396] get_signal+0x468/0x744 > [ 120.915643][ T4396] do_signal+0x84/0x280 > [ 120.919650][ T4396] do_notify_resume+0xd0/0x218 > [ 120.924262][ T4396] work_pending+0xc/0x3f0 > If you would like, you can use git notes to add the trace as well to the notes summary of the patches you send out. This isn't a must but in case you want to provide additional context in the future without having this be a part of the commit message body. https://git-scm.com/docs/git-format-patch#Documentation/git-format-patch.txt---notesltrefgt > > > > > > > > > > At 2023-10-23 23:03:35, "Rahul Rameshbabu" <sergeantsagara@xxxxxxxxxxxxxx> wrote: >>Hi Charles, >> >>On Mon, 23 Oct, 2023 17:35:00 +0800 "Charles Yi" <be286@xxxxxxx> wrote: >>> hid_debug_events_release() access released memory by >>> hid_device_release(). This is fixed by the patch. >>> >> >>A couple of things here. Can you add a Fixes: tag? >> >>https://www.kernel.org/doc/html/latest/process/submitting-patches.html#describe-your-changes >> >>Before any v2 however, it would be nice to understand where this issue >>is coming from. I am wondering if it's really a core issue or rather an >>issue with a higher level device specific driver making use of the hid >>subsystem. I am having a hard time seeing how this issue occurs >>currently. A stack trace in a follow-up email to this one pertaining to >>the crash would be helpful. If you are resolving a syzbot report, a link >>to that report would suffice. >> >>This patch doesn't make a lot of sense to me as-is because >>hid_debug_events_release is about release resources related to hid debug >>events (at least from my current understanding). It should not be >>free-ing the underlying hid device/instance itself. >> >>> Signed-off-by: Charles Yi <be286@xxxxxxx> >>> --- [...] Sorry for the delay in being able to review this. Excited to see a v2 with a Fixes: tag. -- Thanks, Rahul Rameshbabu
