Very rarely crash when tempesta shutdown

[EvgeniiMekhanik]

[ 4704.905911] End test: http2_general.test_h2_frame.TestH2Frame.test_rst_frame_in_response
[ 4705.742973] BUG: unable to handle page fault for address: ffffffffffffffff
[ 4705.743960] #PF: supervisor write access in kernel mode
[ 4705.744510] #PF: error_code(0x0002) - not-present page
[ 4705.745017] PGD 1b4c15067 P4D 1b4c15067 PUD 1b4c17067 PMD 0
[ 4705.745679] Oops: 0002 [#1] SMP NOPTI
[ 4705.746094] CPU: 2 PID: 15469 Comm: python3 Tainted: G W OE 5.10.35+ #241
[ 4705.746727] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
[ 4705.747211] RIP: 0010:detach_if_pending+0x31/0xb0
[ 4705.747486] Code: 47 08 48 85 c0 0f 84 9b 00 00 00 55 48 89 e5 41 54 41 89 d4 53 48 83 3f 00 48 89 fb 74 69 0f 1f 44 00 00 48 8b 03 48 8b 53 08 <48> 89 02 48 85 c0 74 04 48 89 50 08 45 84 e4 74 08 48 c7 43 08 00
[ 4705.748825] RSP: 0018:ffffb2df8012ca58 EFLAGS: 00010086
[ 4705.749154] RAX: dead000000000122 RBX: ffff8915ec1c8048 RCX: 0000000000000019
[ 4705.749565] RDX: ffffffffffffffff RSI: ffff8917f7c1cc80 RDI: ffff8915ec1c8048
[ 4705.749984] RBP: ffffb2df8012ca68 R08: 0000000000000000 R09: ffffffff9c094960
[ 4705.750394] R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
[ 4705.750805] R13: ffff8917f7c1cc80 R14: 0000000000000001 R15: 0000000000000000
[ 4705.751241] FS: 0000000000000000(0000) GS:ffff8917f7c80000(0000) knlGS:0000000000000000
[ 4705.751851] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 4705.752315] CR2: ffffffffffffffff CR3: 00000001b4c10000 CR4: 0000000000750ee0
[ 4705.752821] PKRU: 55555554
[ 4705.753012] Call Trace:
[ 4705.753159]
[ 4705.753281] __mod_timer+0x170/0x4f0
[ 4705.753492] ? tcp_ack_update_rtt+0x132/0x450
[ 4705.753780] mod_timer+0x10/0x20
[ 4705.754016] tfw_sock_srv_connect_try_later+0x90/0x210 [tempesta_fw]
[ 4705.754452] ? tfw_http_conn_release+0x3b/0x290 [tempesta_fw]
[ 4705.754902] tfw_srv_conn_release+0x5d/0xc0 [tempesta_fw]
[ 4705.755255] tfw_sock_srv_connect_drop+0x182/0x190 [tempesta_fw]
[ 4705.755688] ss_conn_drop_guard_exit+0x26/0x50 [tempesta_fw]
[ 4705.756185] tcp_done+0xc9/0x140
[ 4705.756415] tcp_rcv_state_process+0xbee/0x1080
[ 4705.756734] ? sk_filter_trim_cap+0xde/0x240
[ 4705.757069] ? tcp_v4_inbound_md5_hash+0x57/0x1b0
[ 4705.757391] tcp_v4_do_rcv+0xc4/0x200
[ 4705.757644] tcp_v4_rcv+0xcd0/0xe20
[ 4705.757886] ip_protocol_deliver_rcu+0x44/0x230
[ 4705.758216] ip_local_deliver_finish+0x48/0x60
[ 4705.758590] ip_local_deliver+0xf8/0x110
[ 4705.758900] ? ip_protocol_deliver_rcu+0x230/0x230

[EvgeniiMekhanik]

Run any test with TCP segmentation, stop it using Ctrl + C.

[EvgeniiMekhanik]

I can't reproduce this problem again. The problem was in accessing of some Tempesta structure after Tempesta unload. I'm not sure that I didn't catch this bug on my Tempesta branch where I broke something myself.