Kernel panic at lpfc_dev_loss_tmo_callbk() with NULL pointer dereference after FC link down and up

Issue

• The system panicked with a NULL pointer dereference in lpfc_dev_loss_tmo_callbk() after the FC links of an lpfc HBA went down and came back up.

[  389.807380]  rport-6:0-6: blocked FC remote port time out: removing rport
[  389.807386]  rport-6:0-4: blocked FC remote port time out: removing rport
[  389.807388]  rport-6:0-5: blocked FC remote port time out: removing rport
[  389.807390]  rport-6:0-3: blocked FC remote port time out: removing rport
[  389.807391]  rport-6:0-2: blocked FC remote port time out: removing rport
[  389.807393]  rport-6:0-1: blocked FC remote port time out: removing rport
[  389.807394]  rport-6:0-0: blocked FC remote port time out: removing rport
[  389.807397] **** lpfc_rport_invalid: Null vport on ndlp xff2377d8866cf200, DID xfffc01 rport xff2377d8866da000 SID xffffffff
[  389.807402] BUG: kernel NULL pointer dereference, address: 0000000000000000
[  389.807403] #PF: supervisor read access in kernel mode
[  389.807404] #PF: error_code(0x0000) - not-present page
[  389.807406] PGD c124d59067 P4D 0 
[  389.807408] Oops: 0000 [#1] PREEMPT SMP NOPTI
[  389.807410] CPU: 48 PID: 997 Comm: kworker/48:1 Kdump: loaded Not tainted 5.14.0-570.119.1.el9_6.x86_64 #1
[  389.807412] Hardware name: Dell Inc. PowerEdge R7725/0KRFPX, BIOS 1.7.6 05/04/2026
[  389.807413] Workqueue: fc_wq_6 fc_rport_final_delete [scsi_transport_fc]
[  389.807423] RIP: 0010:lpfc_dev_loss_tmo_callbk+0x54/0x420 [lpfc]
[  389.807443] Code: 01 00 00 0f b7 8d b4 00 00 00 48 c7 c2 58 d4 12 c1 48 89 fb 44 8b 8d 98 00 00 00 44 8b 85 a0 00 00 00 be 80 00 00 00 4c 89 e7 <4d> 8b 2c 24 e8 93 04 04 00 48 8b 95 10 01 00 00 8b 82 2c 03 00 00
[  389.807443] RSP: 0018:ff5f8ea41b553e20 EFLAGS: 00010286
[  389.807445] RAX: ff2377d8866da538 RBX: ff2377d8866da000 RCX: 000000000000ffff
[  389.807446] RDX: ffffffffc112d458 RSI: 0000000000000080 RDI: 0000000000000000
[  389.807446] RBP: ff2377d8866cf200 R08: 0000000000fffc01 R09: 0000000000000000
[  389.807447] R10: ff5f8ea41b553d00 R11: ffffffffaa3e1888 R12: 0000000000000000
[  389.807447] R13: ff2377d8866da000 R14: ff237894c4426000 R15: 0000000000000000
[  389.807448] FS:  0000000000000000(0000) GS:ff2379579d400000(0000) knlGS:0000000000000000
[  389.807448] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  389.807449] CR2: 0000000000000000 CR3: 000000030940e004 CR4: 0000000000771ef0
[  389.807449] PKRU: 55555554
[  389.807450] Call Trace:
[  389.807451]  <TASK>
[  389.807453]  ? show_trace_log_lvl+0x1c4/0x2df
[  389.807458]  ? show_trace_log_lvl+0x1c4/0x2df
[  389.807460]  ? fc_rport_final_delete+0xe7/0x1b0 [scsi_transport_fc]
[  389.807463]  ? __die_body.cold+0x8/0xd
[  389.807464]  ? page_fault_oops+0x134/0x170
[  389.807467]  ? _prb_read_valid+0x81/0xe0
[  389.807470]  ? exc_page_fault+0x62/0x150
[  389.807472]  ? asm_exc_page_fault+0x22/0x30
[  389.807477]  ? lpfc_dev_loss_tmo_callbk+0x54/0x420 [lpfc]
[  389.807487]  fc_rport_final_delete+0xe7/0x1b0 [scsi_transport_fc]
[  389.807491]  process_one_work+0x194/0x380
[  389.807494]  worker_thread+0x2fe/0x410
[  389.807496]  ? __pfx_worker_thread+0x10/0x10
[  389.807497]  kthread+0xdd/0x100
[  389.807498]  ? __pfx_kthread+0x10/0x10
[  389.807499]  ret_from_fork+0x29/0x50
[  389.807502]  </TASK>
[...]
[  389.807550] CR2: 0000000000000000