[PATCH for-next] RDMA/bnxt_re: Fix kernel panic when trying to access bnxt_re_stat_descs

[Kamal Heib <kamalheib1@gmail.com>]

For some reason when introducing 13f30b0fa0a9 commit the "active_pds" and
"active_ahs" descriptors got dropped, which lead to the following panic
when trying to access the first entry in the descriptors. Avoid this by
return the dropped hunks.

 bnxt_re: Broadcom NetXtreme-C/E RoCE Driver
 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 PTI
 CPU: 2 PID: 594 Comm: kworker/u32:1 Not tainted 5.15.0-rc6+ #2
 Hardware name: Dell Inc. PowerEdge R430/0CN7X8, BIOS 2.12.1 12/07/2020
 Workqueue: bnxt_re bnxt_re_task [bnxt_re]
 RIP: 0010:strlen+0x0/0x20
 Code: 48 89 f9 74 09 48 83 c1 01 80 39 00 75 f7 31 d2 44 0f b6 04 16 44 88 04 11 48 83 c2 01 45 84 c0 75 ee c3 0f 1f 80 00 00 00 00 <80> 3f 00 74 10 48 89 f8 48 83 c0 01 80 31
 RSP: 0018:ffffb25fc47dfbb0 EFLAGS: 00010246
 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000008100
 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
 RBP: 0000000000000000 R08: 00000000fffffff4 R09: 0000000000000000
 R10: ffff8a05c71fc028 R11: 0000000000000000 R12: 0000000000000000
 R13: 0000000000000000 R14: 0000000000000000 R15: ffff8a05c3dee800
 FS:  0000000000000000(0000) GS:ffff8a092fc40000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 0000000000000000 CR3: 000000048d3da001 CR4: 00000000001706e0
 Call Trace:
  kernfs_name_hash+0x12/0x80
  kernfs_find_ns+0x35/0xd0
  kernfs_remove_by_name_ns+0x32/0x90
  remove_files+0x2b/0x60
  create_files+0x1d3/0x1f0
  internal_create_group+0x17b/0x1f0
  internal_create_groups.part.0+0x3d/0xa0
  setup_port+0x180/0x3b0 [ib_core]
  ? __cond_resched+0x16/0x40
  ? kmem_cache_alloc_trace+0x278/0x3d0
  ib_setup_port_attrs+0x99/0x240 [ib_core]
  ib_register_device+0xcc/0x160 [ib_core]
  bnxt_re_task+0xba/0x170 [bnxt_re]
  process_one_work+0x1eb/0x390
  worker_thread+0x53/0x3d0
  ? process_one_work+0x390/0x390
  kthread+0x10f/0x130
  ? set_kthread_struct+0x40/0x40
  ret_from_fork+0x22/0x30
 Modules linked in: bnxt_re kvm ib_uverbs dell_wmi_descriptor rfkill video iTCO_wdt iTCO_vendor_support irqbypass dcdbas ib_core ipmi_ssif rapl intel_cstate intel_uncore pcspke
 CR2: 0000000000000000
 ---[ end trace b4637e4c4e3001af ]---
 RIP: 0010:strlen+0x0/0x20
 Code: 48 89 f9 74 09 48 83 c1 01 80 39 00 75 f7 31 d2 44 0f b6 04 16 44 88 04 11 48 83 c2 01 45 84 c0 75 ee c3 0f 1f 80 00 00 00 00 <80> 3f 00 74 10 48 89 f8 48 83 c0 01 80 31
 RSP: 0018:ffffb25fc47dfbb0 EFLAGS: 00010246
 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000008100
 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
 RBP: 0000000000000000 R08: 00000000fffffff4 R09: 0000000000000000
 R10: ffff8a05c71fc028 R11: 0000000000000000 R12: 0000000000000000
 R13: 0000000000000000 R14: 0000000000000000 R15: ffff8a05c3dee800
 FS:  0000000000000000(0000) GS:ffff8a092fc40000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 0000000000000000 CR3: 000000048d3da001 CR4: 00000000001706e0
 Kernel panic - not syncing: Fatal exception
 Kernel Offset: 0x400000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff)
 ---[ end Kernel panic - not syncing: Fatal exception ]---

Fixes: 13f30b0fa0a9 ("RDMA/counter: Add a descriptor in struct rdma_hw_stats")
Signed-off-by: Kamal Heib <kamalheib1@gmail.com>
---
 drivers/infiniband/hw/bnxt_re/hw_counters.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/infiniband/hw/bnxt_re/hw_counters.c b/drivers/infiniband/hw/bnxt_re/hw_counters.c
index 78ca6dfd182b..825d512799d9 100644
--- a/drivers/infiniband/hw/bnxt_re/hw_counters.c
+++ b/drivers/infiniband/hw/bnxt_re/hw_counters.c
@@ -58,6 +58,8 @@
 #include "hw_counters.h"
 
 static const struct rdma_stat_desc bnxt_re_stat_descs[] = {
+	[BNXT_RE_ACTIVE_PD].name		=  "active_pds",
+	[BNXT_RE_ACTIVE_AH].name		=  "active_ahs",
 	[BNXT_RE_ACTIVE_QP].name		=  "active_qps",
 	[BNXT_RE_ACTIVE_SRQ].name		=  "active_srqs",
 	[BNXT_RE_ACTIVE_CQ].name		=  "active_cqs",
-- 
2.31.1