Messages in this thread | | | Date | Wed, 30 Mar 2022 16:53:41 +0530 | Subject | Re: Possible case of Race in kobject_get_path() | From | Mukesh Ojha <> |
| |
On 3/30/2022 4:49 PM, Greg KH wrote: > On Wed, Mar 30, 2022 at 04:44:26PM +0530, Mukesh Ojha wrote: >> On 3/30/2022 4:31 PM, Greg KH wrote: >>> On Wed, Mar 30, 2022 at 04:14:11PM +0530, Mukesh Ojha wrote: >>>> On 3/30/2022 3:46 PM, Greg KH wrote: >>>>> On Wed, Mar 30, 2022 at 03:41:04PM +0530, Mukesh Ojha wrote: >>>>>> Hi All, >>>>>> >>>>>> We are facing one issue where one driver (p1) is trying to register its >>>>>> device from driver probe >>>>>> and from another path (p2) dev_set_name(new name) done from driver probe of >>>>>> the added device whose >>>>>> new name length can be more than earlier done in (p1 path) which could >>>>>> result in redzone overwritten issue. >>>>> I do not understand, what specific driver is doing this so that we can >>>>> see an example of this problem? >>>> trying to paste some logs of the race. >>>> >>>> [ 14.235820][ T503] BUG kmalloc-128 (Tainted: G S O ): Left Redzone >>>> overwritten >>> What kernel version is this? >> 5.10 > That is very old, is this an issue in 5.17? > >>>> [ 14.244189][ T503] >>>> ----------------------------------------------------------------------------- >>>> [ 14.255241][ T503] INFO: 0xffffff87caae0f7d-0xffffff87caae0f7f >>>> @offset=3965. First byte 0x2f instead of 0xcc >>>> [ 14.265176][ T503] INFO: Allocated in kobject_get_path+0x58/0x100 age=1 >>>> cpu=0 pid=503 >>>> [ 14.273111][ T503] kobject_get_path+0x58/0x100 >>>> [ 14.277747][ T503] kobject_uevent_env+0x120/0x744 >>>> [ 14.282639][ T503] device_add+0x98c/0x1028 >>>> [ 14.286925][ T503] *device_register+0x24/0x38* >>>> [ 14.291395][ T503] slim_alloc_device+0xdc/0x108 [slimbus] >>>> [ 14.296992][ T503] slim_register_controller+0x210/0x2ac [slimbus] >>>> [ 14.303291][ T503] qcom_slim_ngd_probe+0x3c/0x348 [slim_qcom_ngd_ctrl] >>>> [ 14.310007][ T503] platform_drv_probe+0x60/0x180 >>>> [ 14.314812][ T503] really_probe+0x208/0xb64 >>>> [ 14.319184][ T503] driver_probe_device+0x130/0x254 >>>> [ 14.324159][ T503] __device_attach_driver+0x1e8/0x324 >>>> [ 14.329399][ T503] __device_attach+0x170/0x364 >>>> [ 14.334035][ T503] bus_probe_device+0x4c/0x164 >>>> [ 14.338671][ T503] device_add+0xa60/0x1028 >>>> [ 14.342957][ T503] platform_device_add+0x260/0x2c8 >>>> [ 14.347941][ T503] qcom_slim_ngd_ctrl_probe+0x71c/0x804 >>>> [slim_qcom_ngd_ctrl] >>>> [ 14.355177][ T503] INFO: Freed in kobject_uevent_env+0x210/0x744 age=1 >>>> cpu=4 pid=518 >>>> [ 14.363018][ T503] do_init_module+0xac/0x494 >>>> [ 14.367475][ T503] load_module+0x35c0/0x3e54 >>>> [ 14.371930][ T503] __se_sys_finit_module+0x188/0x1c8 >>>> [ 14.377086][ T503] __arm64_sys_finit_module+0x20/0x30 >>>> [ 14.382328][ T503] el0_svc_common+0xdc/0x294 >>>> [ 14.386786][ T503] el0_svc+0x38/0x9c >>>> [ 14.390552][ T503] el0_sync_handler+0x8c/0xf0 >>>> >>>> >>>> [ 14.490994*][ T503] Redzone ffffff87caae0f7**0*: cc cc cc cc cc cc cc cc cc >>>> cc cc cc cc 2f 64 65 .............*/de* >>>> [ 14.501185][ T503] Object ffffff87caae0f80: 76 69 63 65 73 2f 70 6c 61 74 >>>> 66 6f 72 6d 2f 73 vices/platform/s >>>> [ 14.511376][ T503] Object ffffff87caae0f90: 6f 63 2f 33 33 34 30 30 30 30 >>>> 2e 73 6c 69 6d 2f oc/3340000.slim/ >>>> [ 14.521566][ T503] Object ffffff87caae0fa0: 71 63 6f 6d 2c 73 6c 69 6d 2d >>>> 6e 67 64 2e 31 2f qcom,slim-ngd.1/ >>>> [ 14.531757][ T503] Object ffffff87caae0fb0: 62 74 66 6d 73 6c 69 6d 5f 73 >>>> 6c 61 76 65 00 00 *btfmslim_slave*.. >>>> >>>> >>>> >>>> 499 static int btfm_slim_probe(struct slim_device *slim) >>> I do not see that function in Linus's tree right now. Where does it >>> come from? >> Don't you think, it can be caused by any kernel module. > Kernel code do not protect themselves against other kernel code doing > abusive things. > > Perhaps fix your out-of-tree code to not do this if no in-kernel code is > doing this? Nothing we can do at all about out-of-tree code that we > have never seen.
Thanks for the comment, Greg. Why do we make dev_set_name() make it available to module apart from the core ?
-Mukesh
> > Best of luck! > > greg k-h
| |