Comment 0 for bug 1928328

This happens every time booting. Reproducible with Canonical linux-intel (from ppa:canonical-kernel-team/ppa, focal pocket) and mainline v5.13-rc1. Elkhart Lake CRB FAB-B Rev-201, CPU QWW1, BIOS EHLSFWI1.R00.3044.A01.2101210945 01/21/2021.

This also causes a few seconds pause during the boot process, and blocks reboot process.

 BUG: kernel NULL pointer dereference, address: 0000000000000000
 #PF: supervisor read access in kernel mode
 #PF: error_code(0x0000) - not-present page
 PGD 0 P4D 0
 Oops: 0000 [#1] SMP NOPTI
 CPU: 2 PID: 168 Comm: systemd-udevd Not tainted 5.11.0-1003-intel #3-Ubuntu
 Hardware name: Intel Corporation Elkhart Lake Embedded Platform/ElkhartLake LPDDR4x T3 CRB, BIOS EHLSFWI1.R00.3044.A01.2101210945 01/21/2021
 RIP: 0010:strcmp+0xc/0x20
 Code: 06 49 89 f8 48 83 c6 01 48 83 c7 01 88 47 ff 84 c0 75 eb 4c 89 c0 c3 0f 1f 80 00 00 00 00 31 c0 eb 08 48 83 c0 01 84 d2 74 0f <0f> b6 14 07 3a 14 06 74 ef 19 c0 83 c8 01 c3 31 c0 c3 66 90 48 85
 RSP: 0018:ffffa09e0050ba90 EFLAGS: 00010246
 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffa09e0050ba18
 RDX: 0000000000000000 RSI: ffffffffc00dfc7b RDI: 0000000000000000
 RBP: ffffa09e0050bab8 R08: 0000000000000000 R09: ffffa09e0050b808
 R10: ffff8ebf0c3d33ff R11: 0000000000000000 R12: ffffffffc00e1c20
 R13: ffffffffc00e30e0 R14: 0000000000000000 R15: 0000000000000002
 FS: 00007ff28eb16880(0000) GS:ffff8ebfe4300000(0000) knlGS:0000000000000000
 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 0000000000000000 CR3: 0000000102658000 CR4: 0000000000350ee0
 Call Trace:
  ? intel_pinctrl_get_soc_data+0x67/0xc0
  intel_pinctrl_probe_by_uid+0x13/0x30
  platform_probe+0x45/0xa0
  really_probe+0xfb/0x420
  driver_probe_device+0xe9/0x160
  device_driver_attach+0x5d/0x70
  __driver_attach+0x8f/0x150
  ? device_driver_attach+0x70/0x70
  bus_for_each_dev+0x7e/0xc0
  driver_attach+0x1e/0x20
  bus_add_driver+0x152/0x1f0
  driver_register+0x74/0xd0
  ? 0xffffffffc00e6000
  __platform_driver_register+0x1e/0x20
  ehl_pinctrl_driver_init+0x1c/0x1000 [pinctrl_elkhartlake]
  do_one_initcall+0x48/0x1d0
  ? _cond_resched+0x19/0x30
  ? kmem_cache_alloc_trace+0x380/0x430
  ? do_init_module+0x28/0x250
  do_init_module+0x62/0x250
  load_module+0x11aa/0x1370
  ? security_kernel_post_read_file+0x5c/0x70
  ? security_kernel_post_read_file+0x5c/0x70
  __do_sys_finit_module+0xc2/0x120
  ? __do_sys_finit_module+0xc2/0x120
  __x64_sys_finit_module+0x1a/0x20
  do_syscall_64+0x38/0x90
  entry_SYSCALL_64_after_hwframe+0x44/0xa9
 RIP: 0033:0x7ff28f09889d
 Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d c3 f5 0c 00 f7 d8 64 89 01 48
 RSP: 002b:00007ffd618ed1a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
 RAX: ffffffffffffffda RBX: 0000563511b5c430 RCX: 00007ff28f09889d
 RDX: 0000000000000000 RSI: 00007ff28ef75ded RDI: 0000000000000005
 RBP: 0000000000020000 R08: 0000000000000000 R09: 0000000000000000
 R10: 0000000000000005 R11: 0000000000000246 R12: 00007ff28ef75ded
 R13: 0000000000000000 R14: 0000563511b603c0 R15: 0000563511b5c430
 Modules linked in: pinctrl_elkhartlake(+)
 CR2: 0000000000000000
 ---[ end trace 2004c11402add586 ]---