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. 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 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> >> --- >> drivers/hid/hid-core.c | 12 ++++++++++-- >> drivers/hid/hid-debug.c | 3 +++ >> include/linux/hid.h | 3 +++ >> 3 files changed, 16 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c >> index 8992e3c1e769..e0181218ad85 100644 >> --- a/drivers/hid/hid-core.c >> +++ b/drivers/hid/hid-core.c >> @@ -702,15 +702,22 @@ static void hid_close_report(struct hid_device *device) >> * Free a device structure, all reports, and all fields. >> */ >> >> -static void hid_device_release(struct device *dev) >> +void hiddev_free(struct kref *ref) >> { >> - struct hid_device *hid = to_hid_device(dev); >> + struct hid_device *hid = container_of(ref, struct hid_device, ref); >> >> hid_close_report(hid); >> kfree(hid->dev_rdesc); >> kfree(hid); >> } >> >> +static void hid_device_release(struct device *dev) >> +{ >> + struct hid_device *hid = to_hid_device(dev); >> + >> + kref_put(&hid->ref, hiddev_free); >> +} >> + >> /* >> * Fetch a report description item from the data stream. We support long >> * items, though they are not used yet. >> @@ -2846,6 +2853,7 @@ struct hid_device *hid_allocate_device(void) >> spin_lock_init(&hdev->debug_list_lock); >> sema_init(&hdev->driver_input_lock, 1); >> mutex_init(&hdev->ll_open_lock); >> + kref_init(&hdev->ref); >> >> hid_bpf_device_init(hdev); >> >> diff --git a/drivers/hid/hid-debug.c b/drivers/hid/hid-debug.c >> index e7ef1ea107c9..7dd83ec74f8a 100644 >> --- a/drivers/hid/hid-debug.c >> +++ b/drivers/hid/hid-debug.c >> @@ -1135,6 +1135,7 @@ static int hid_debug_events_open(struct inode *inode, struct file *file) >> goto out; >> } >> list->hdev = (struct hid_device *) inode->i_private; >> + kref_get(&list->hdev->ref); >> file->private_data = list; >> mutex_init(&list->read_mutex); >> >> @@ -1227,6 +1228,8 @@ static int hid_debug_events_release(struct inode *inode, struct file *file) >> list_del(&list->node); >> spin_unlock_irqrestore(&list->hdev->debug_list_lock, flags); >> kfifo_free(&list->hid_debug_fifo); >> + >> + kref_put(&list->hdev->ref, hiddev_free); >> kfree(list); >> >> return 0; >> diff --git a/include/linux/hid.h b/include/linux/hid.h >> index 964ca1f15e3f..3b08a2957229 100644 >> --- a/include/linux/hid.h >> +++ b/include/linux/hid.h >> @@ -679,6 +679,7 @@ struct hid_device { /* device report descriptor */ >> struct list_head debug_list; >> spinlock_t debug_list_lock; >> wait_queue_head_t debug_wait; >> + struct kref ref; >> >> unsigned int id; /* system unique id */ >> >> @@ -687,6 +688,8 @@ struct hid_device { /* device report descriptor */ >> #endif /* CONFIG_BPF */ >> }; >> >> +void hiddev_free(struct kref *ref); >> + >> #define to_hid_device(pdev) \ >> container_of(pdev, struct hid_device, dev) > >-- >Thank you for the patch, > >Rahul Rameshbabu
