The kernel crashes in __list_del_entry_valid() called from iucv_path_sever() due to a known use-after-free bug

Issue

• The kernel crashes in __list_del_entry_valid() called from iucv_path_sever() due to a known use-after-free bug.

[195054.990461] Unable to handle kernel pointer dereference in virtual kernel address space
[195054.990472] Failing address: 1fe7c34a1ba01000 TEID: 1fe7c34a1ba01803
[195054.990475] Fault in home space mode while using kernel ASCE.
[195054.990477] AS:0000000e6a258007 R3:0000000000000024 
[195054.990498] Oops: 0038 ilc:3 [#1] SMP 
[195054.990502] Modules linked in: ...
[195054.990559] Red Hat flags: eBPF/event
[195054.990561] CPU: 2 PID: 2325 Comm: iucvserv Kdump: loaded Tainted: G           OE     -------- -  - 4.18.0-553.el8_10.s390x #1
[195054.990563] Hardware name: IBM 3931 LA1 401 (z/VM 7.3.0)
[195054.990564] Krnl PSW : 0704e00180000000 0000000e693c0856 (__list_del_entry_valid+0x3e/0xc0)
[195054.990571]            R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:2 PM:0 RI:0 EA:3
[195054.990573] Krnl GPRS: 000000000000000f 000000016a858318 000000016a858318 1fe7c34a1ba017ef
[195054.990575]            0000000000000200 0000000000000000 0000000000000000 000000008650ba20
[195054.990577]            000003ff803c2bca 000003ff00000001 000000016a858318 000000016a858300
[195054.990578]            00000000ddca0000 0000000126a03710 00000000e23d7c20 00000000e23d7c08
[195054.990585] Krnl Code: 0000000e693c0846: ec14001b8064   cgrj    %r1,%r4,8,e693c087c
                           0000000e693c084c: a7490200       lghi    %r4,512
                          #0000000e693c0850: ec3400388064   cgrj    %r3,%r4,8,e693c08c0
                          >0000000e693c0856: e34030000004   lg  %r4,0(%r3)
                           0000000e693c085c: ec4200286064   cgrj    %r4,%r2,6,e693c08ac
                           0000000e693c0862: e34010080020   cg  %r4,8(%r1)
                           0000000e693c0868: a7740014       brc 7,e693c0890
                           0000000e693c086c: a7290001       lghi    %r2,1
[195054.990619] Call Trace:
[195054.990620] ([<000000016a858300>] 0x16a858300)
[195054.990624]  [<0000000e6971cd9e>] iucv_path_sever+0x96/0x138 
[195054.990633]  [<000003ff803c2bca>] iucv_sever_path+0xc2/0xd0 [af_iucv] 
[195054.990639]  [<000003ff803c51b6>] iucv_sock_close+0xa6/0x310 [af_iucv] 
[195054.990643]  [<000003ff803c58cc>] iucv_sock_release+0x3c/0xd0 [af_iucv] 
[195054.990647]  [<0000000e695340e6>] __sock_release+0x5e/0xe8 
[195054.990652]  [<0000000e695341a4>] sock_close+0x34/0x48 
[195054.990656]  [<0000000e6920c742>] __fput+0xba/0x268 
[195054.990662]  [<0000000e68f9bb3c>] task_work_run+0xbc/0xf0 
[195054.990672]  [<0000000e68f2d718>] do_notify_resume+0x88/0x90 
[195054.990676]  [<0000000e69764f7e>] system_call+0xe2/0x2c8 
[195054.990680] Last Breaking-Event-Address:
[195054.990681]  [<0000000e6971cd98>] iucv_path_sever+0x90/0x138
[195054.990687]  
[195054.990688] Kernel panic - not syncing: Fatal exception in interrupt