On Fri, 2022-04-29 at 08:23 -0400, Prarit Bhargava wrote:
> 'rmmod pmt_telemetry' panics with:
>
> BUG: kernel NULL pointer dereference, address: 0000000000000040
> #PF: supervisor read access in kernel mode
> #PF: error_code(0x0000) - not-present page
> PGD 0 P4D 0
> Oops: 0000 [#1] PREEMPT SMP NOPTI
> CPU: 4 PID: 1697 Comm: rmmod Tainted: G S W --------
> --- 5.18.0-rc4 #3
> Hardware name: Intel Corporation Alder Lake Client Platform/AlderLake-P DDR5
> RVP, BIOS ADLPFWI1.R00.3056.B00.2201310233 01/31/2022
> RIP: 0010:device_del+0x1b/0x3d0
> Code: e8 1a d9 e9 ff e9 58 ff ff ff 48 8b 08 eb dc 0f 1f 44 00 00 41 56 41 55
> 41 54 55 48 8d af 80 00 00 00 53 48 89 fb 48 83 ec 18 <4c> 8b 67 40 48 89 ef
> 65 48 8b 04 25 28 00 00 00 48 89 44 24 10 31
> RSP: 0018:ffffb520415cfd60 EFLAGS: 00010286
> RAX: 0000000000000070 RBX: 0000000000000000 RCX: 0000000000000000
> RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000000
> RBP: 0000000000000080 R08: ffffffffffffffff R09: ffffb520415cfd78
> R10: 0000000000000002 R11: ffffb520415cfd78 R12: 0000000000000000
> R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
> FS: 00007f7e198e5740(0000) GS:ffff905c9f700000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000000000000040 CR3: 000000010782a005 CR4: 0000000000770ee0
> PKRU: 55555554
> Call Trace:
> <TASK>
> ? __xa_erase+0x53/0xb0
> device_unregister+0x13/0x50
> intel_pmt_dev_destroy+0x34/0x60 [pmt_class]
> pmt_telem_remove+0x40/0x50 [pmt_telemetry]
> auxiliary_bus_remove+0x18/0x30
> device_release_driver_internal+0xc1/0x150
> driver_detach+0x44/0x90
> bus_remove_driver+0x74/0xd0
> auxiliary_driver_unregister+0x12/0x20
> pmt_telem_exit+0xc/0xe4a [pmt_telemetry]
> __x64_sys_delete_module+0x13a/0x250
> ? syscall_trace_enter.isra.19+0x11e/0x1a0
> do_syscall_64+0x58/0x80
> ? syscall_exit_to_user_mode+0x12/0x30
> ? do_syscall_64+0x67/0x80
> ? syscall_exit_to_user_mode+0x12/0x30
> ? do_syscall_64+0x67/0x80
> ? syscall_exit_to_user_mode+0x12/0x30
> ? do_syscall_64+0x67/0x80
> ? exc_page_fault+0x64/0x140
> entry_SYSCALL_64_after_hwframe+0x44/0xae
> RIP: 0033:0x7f7e1803a05b
> Code: 73 01 c3 48 8b 0d 2d 4e 38 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f
> 84 00 00 00 00 00 90 f3 0f 1e fa b8 b0 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73
> 01 c3 48 8b 0d fd 4d 38 00 f7 d8 64 89 01 48
>
> The probe function, pmt_telem_probe(), adds an entry for devices even if
> they have not been initialized. This results in the array of initialized
> devices containing both initialized and uninitialized entries. This
> causes a panic in the remove function, pmt_telem_remove() which expects
> the array to only contain initialized entries.
>
> Only use an entry when a device is initialized.
>
> Cc: "David E. Box" <david.e.box@xxxxxxxxxxxxxxx>
> Cc: Hans de Goede <hdegoede@xxxxxxxxxx>
> Cc: Mark Gross <markgross@xxxxxxxxxx>
> Cc: platform-driver-x86@xxxxxxxxxxxxxxx
> Signed-off-by: David Arcari <darcari@xxxxxxxxxx>
> Signed-off-by: Prarit Bhargava <prarit@xxxxxxxxxx>
> ---
> drivers/platform/x86/intel/pmt/telemetry.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/platform/x86/intel/pmt/telemetry.c
> b/drivers/platform/x86/intel/pmt/telemetry.c
> index 6b6f3e2a617a..f73ecfd4a309 100644
> --- a/drivers/platform/x86/intel/pmt/telemetry.c
> +++ b/drivers/platform/x86/intel/pmt/telemetry.c
> @@ -103,7 +103,7 @@ static int pmt_telem_probe(struct auxiliary_device
> *auxdev, const struct auxilia
> auxiliary_set_drvdata(auxdev, priv);
>
> for (i = 0; i < intel_vsec_dev->num_resources; i++) {
> - struct intel_pmt_entry *entry = &priv->entry[i];
> + struct intel_pmt_entry *entry = &priv->entry[priv->num_entries];
>
> ret = intel_pmt_dev_create(entry, &pmt_telem_ns, intel_vsec_dev,
> i);
> if (ret < 0)
The unused entries are at the end of the array on Tiger Lake, so we missed
catching this. Thanks for the fix.
Reviewed-by: David E. Box <david.e.box@xxxxxxxxxxxxxxx>
