Re: [Intel-wired-lan] [PATCH iwl-net] idpf: clear stale cdev_info ptr

[Simon Horman <horms@kernel.org>]

On Mon, Mar 02, 2026 at 05:28:31PM -0800, Joshua Hay wrote:
> Deinit calls idpf_idc_deinit_core_aux_device to free the cdev_info
> memory, but leaves the adapter->cdev_info field with a stale pointer
> value. This will bypass subsequent "if (!cdev_info)" checks if cdev_info
> is not reallocated. For example, if idc_init fails after a reset,
> cdev_info will already have been freed during the reset handling, but it
> will not have been reallocated. The next reset or rmmod will result in a
> crash.
> 
> [  +0.000008] BUG: kernel NULL pointer dereference, address: 00000000000000d0
> [  +0.000033] #PF: supervisor read access in kernel mode
> [  +0.000020] #PF: error_code(0x0000) - not-present page
> [  +0.000017] PGD 2097dfa067 P4D 0
> [  +0.000017] Oops: Oops: 0000 [#1] SMP NOPTI
> ...
> [  +0.000018] RIP: 0010:device_del+0x3e/0x3d0
> [  +0.000010] Call Trace:
> [  +0.000010]  <TASK>
> [  +0.000012]  idpf_idc_deinit_core_aux_device+0x36/0x70 [idpf]
> [  +0.000034]  idpf_vc_core_deinit+0x3e/0x180 [idpf]
> [  +0.000035]  idpf_remove+0x40/0x1d0 [idpf]
> [  +0.000035]  pci_device_remove+0x42/0xb0
> [  +0.000020]  device_release_driver_internal+0x19c/0x200
> [  +0.000024]  driver_detach+0x48/0x90
> [  +0.000018]  bus_remove_driver+0x6d/0x100
> [  +0.000023]  pci_unregister_driver+0x2e/0xb0
> [  +0.000022]  __do_sys_delete_module.isra.0+0x18c/0x2b0
> [  +0.000025]  ? kmem_cache_free+0x2c2/0x390
> [  +0.000023]  do_syscall_64+0x107/0x7d0
> [  +0.000023]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
> 
> Pass the adapter struct into idpf_idc_deinit_core_aux_device instead and
> clear the cdev_info ptr.
> 
> Fixes: f4312e6bfa2a ("idpf: implement core RDMA auxiliary dev create, init, and destroy")
> Signed-off-by: Joshua Hay <joshua.a.hay@intel.com>
> Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
> Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>

Reviewed-by: Simon Horman <horms@kernel.org>