Message-ID: <4c251905-308b-4709-8e08-39cda85678f9@linux.dev>
Date: Thu, 9 Nov 2023 10:50:44 +0000
From: Vadim Fedorenko <vadim.fedorenko@...ux.dev>
To: Arkadiusz Kubalewski <arkadiusz.kubalewski@...el.com>,
 netdev@...r.kernel.org
Cc: jiri@...nulli.us, michal.michalik@...el.com, milena.olech@...el.com,
 pabeni@...hat.com, kuba@...nel.org
Subject: Re: [PATCH net 0/3] dpll: fix unordered unbind/bind registerer issues

On 08/11/2023 10:32, Arkadiusz Kubalewski wrote:
> Fix issues when performing unordered unbind/bind of a kernel modules
> which are using a dpll device with DPLL_PIN_TYPE_MUX pins.
> Currently only serialized bind/unbind of such use case works, fix
> the issues and allow for unserialized kernel module bind order.
> 
> The issues are observed on the ice driver, i.e.,
> 
> $ echo 0000:af:00.0 > /sys/bus/pci/drivers/ice/unbind
> $ echo 0000:af:00.1 > /sys/bus/pci/drivers/ice/unbind
> 
> results in:
> 
> ice 0000:af:00.0: Removed PTP clock
> BUG: kernel NULL pointer dereference, address: 0000000000000010
> PF: supervisor read access in kernel mode
> PF: error_code(0x0000) - not-present page
> PGD 0 P4D 0
> Oops: 0000 [#1] PREEMPT SMP PTI
> CPU: 7 PID: 71848 Comm: bash Kdump: loaded Not tainted 6.6.0-rc5_next-queue_19th-Oct-2023-01625-g039e5d15e451 #1
> Hardware name: Intel Corporation S2600STB/S2600STB, BIOS SE5C620.86B.02.01.0008.031920191559 03/19/2019
> RIP: 0010:ice_dpll_rclk_state_on_pin_get+0x2f/0x90 [ice]
> Code: 41 57 4d 89 cf 41 56 41 55 4d 89 c5 41 54 55 48 89 f5 53 4c 8b 66 08 48 89 cb 4d 8d b4 24 f0 49 00 00 4c 89 f7 e8 71 ec 1f c5 <0f> b6 5b 10 41 0f b6 84 24 30 4b 00 00 29 c3 41 0f b6 84 24 28 4b
> RSP: 0018:ffffc902b179fb60 EFLAGS: 00010246
> RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
> RDX: ffff8882c1398000 RSI: ffff888c7435cc60 RDI: ffff888c7435cb90
> RBP: ffff888c7435cc60 R08: ffffc902b179fbb0 R09: 0000000000000000
> R10: ffff888ef1fc8050 R11: fffffffffff82700 R12: ffff888c743581a0
> R13: ffffc902b179fbb0 R14: ffff888c7435cb90 R15: 0000000000000000
> FS:  00007fdc7dae0740(0000) GS:ffff888c105c0000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000000000000010 CR3: 0000000132c24002 CR4: 00000000007706e0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> PKRU: 55555554
> Call Trace:
>   <TASK>
>   ? __die+0x20/0x70
>   ? page_fault_oops+0x76/0x170
>   ? exc_page_fault+0x65/0x150
>   ? asm_exc_page_fault+0x22/0x30
>   ? ice_dpll_rclk_state_on_pin_get+0x2f/0x90 [ice]
>   ? __pfx_ice_dpll_rclk_state_on_pin_get+0x10/0x10 [ice]
>   dpll_msg_add_pin_parents+0x142/0x1d0
>   dpll_pin_event_send+0x7d/0x150
>   dpll_pin_on_pin_unregister+0x3f/0x100
>   ice_dpll_deinit_pins+0xa1/0x230 [ice]
>   ice_dpll_deinit+0x29/0xe0 [ice]
>   ice_remove+0xcd/0x200 [ice]
>   pci_device_remove+0x33/0xa0
>   device_release_driver_internal+0x193/0x200
>   unbind_store+0x9d/0xb0
>   kernfs_fop_write_iter+0x128/0x1c0
>   vfs_write+0x2bb/0x3e0
>   ksys_write+0x5f/0xe0
>   do_syscall_64+0x59/0x90
>   ? filp_close+0x1b/0x30
>   ? do_dup2+0x7d/0xd0
>   ? syscall_exit_work+0x103/0x130
>   ? syscall_exit_to_user_mode+0x22/0x40
>   ? do_syscall_64+0x69/0x90
>   ? syscall_exit_work+0x103/0x130
>   ? syscall_exit_to_user_mode+0x22/0x40
>   ? do_syscall_64+0x69/0x90
>   entry_SYSCALL_64_after_hwframe+0x6e/0xd8
> RIP: 0033:0x7fdc7d93eb97
> Code: 0b 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 48 89 54 24 18 48 89 74 24
> RSP: 002b:00007fff2aa91028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
> RAX: ffffffffffffffda RBX: 000000000000000d RCX: 00007fdc7d93eb97
> RDX: 000000000000000d RSI: 00005644814ec9b0 RDI: 0000000000000001
> RBP: 00005644814ec9b0 R08: 0000000000000000 R09: 00007fdc7d9b14e0
> R10: 00007fdc7d9b13e0 R11: 0000000000000246 R12: 000000000000000d
> R13: 00007fdc7d9fb780 R14: 000000000000000d R15: 00007fdc7d9f69e0
>   </TASK>
> Modules linked in: uinput vfio_pci vfio_pci_core vfio_iommu_type1 vfio irqbypass ixgbevf snd_seq_dummy snd_hrtimer snd_seq snd_timer snd_seq_device snd soundcore overlay qrtr rfkill vfat fat xfs libcrc32c rpcrdma sunrpc rdma_ucm ib_srpt ib_isert iscsi_target_mod target_core_mod ib_iser libiscsi scsi_transport_iscsi rdma_cm iw_cm ib_cm intel_rapl_msr intel_rapl_common intel_uncore_frequency intel_uncore_frequency_common isst_if_common skx_edac nfit libnvdimm ipmi_ssif x86_pkg_temp_thermal intel_powerclamp coretemp irdma rapl intel_cstate ib_uverbs iTCO_wdt iTCO_vendor_support acpi_ipmi intel_uncore mei_me ipmi_si pcspkr i2c_i801 ib_core mei ipmi_devintf intel_pch_thermal ioatdma i2c_smbus ipmi_msghandler lpc_ich joydev acpi_power_meter acpi_pad ext4 mbcache jbd2 sd_mod t10_pi sg ast i2c_algo_bit drm_shmem_helper drm_kms_helper ice crct10dif_pclmul ixgbe crc32_pclmul drm crc32c_intel ahci i40e libahci ghash_clmulni_intel libata mdio dca gnss wmi fuse [last unloaded: iavf]
> CR2: 0000000000000010
> 
> Arkadiusz Kubalewski (3):
>    dpll: fix pin dump crash after module unbind
>    dpll: fix pin dump crash for rebound module
>    dpll: fix register pin with unregistered parent pin
> 
>   drivers/dpll/dpll_core.c    |  8 ++------
>   drivers/dpll/dpll_core.h    |  4 ++--
>   drivers/dpll/dpll_netlink.c | 37 ++++++++++++++++++++++---------------
>   3 files changed, 26 insertions(+), 23 deletions(-)
> 


I still don't get how can we end up with unregistered pin. And shouldn't
drivers do unregister of dpll/pin during release procedure? I thought it
was kind of agreement we reached while developing the subsystem.

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