When using 4.18.3-1.el6.elrepo.x86_64 anything that calls the aes_intel module causes significant issues and any process using it just hangs for 15 - 30 minutes. Examples: modprobe -v aesni_intel insmod /lib/modules/2.6.32-754.3.5.el6.x86_64/kernel/crypto/aes_generic.ko insmod /lib/modules/2.6.32-754.3.5.el6.x86_64/kernel/arch/x86/crypto/aes-x86_64.ko insmod /lib/modules/2.6.32-754.3.5.el6.x86_64/kernel/arch/x86/crypto/glue_helper.ko That is as far as it gets, waited 30 minutes. Same command on 2.6.32-754.3.5.el6.x86_64 on same hardware: # modprobe -v aesni_intel insmod /lib/modules/2.6.32-754.3.5.el6.x86_64/kernel/crypto/aes_generic.ko insmod /lib/modules/2.6.32-754.3.5.el6.x86_64/kernel/arch/x86/crypto/aes-x86_64.ko insmod /lib/modules/2.6.32-754.3.5.el6.x86_64/kernel/arch/x86/crypto/glue_helper.ko insmod /lib/modules/2.6.32-754.3.5.el6.x86_64/kernel/crypto/gf128mul.ko insmod /lib/modules/2.6.32-754.3.5.el6.x86_64/kernel/crypto/lrw.ko insmod /lib/modules/2.6.32-754.3.5.el6.x86_64/kernel/crypto/cryptd.ko insmod /lib/modules/2.6.32-754.3.5.el6.x86_64/kernel/arch/x86/crypto/ablk_helper.ko insmod /lib/modules/2.6.32-754.3.5.el6.x86_64/kernel/arch/x86/crypto/aesni-intel.ko When running libguestfs-test-tool with aes enabled in the bios it hangs for up to 30 minutes with: [ 1.096837] general protection fault: 0000 [#1] SMP PTI [ 1.097308] CPU: 0 PID: 271 Comm: cryptomgr_test Not tainted 4.18.3-1.el6.elrepo.x86_64 #1 [ 1.097934] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2007 [ 1.098401] RIP: 0010:aesni_gcm_init+0x89/0x30f [aesni_intel] [ 1.098845] Code: 0f 6f ca 66 0f 73 fa 08 66 0f 73 d9 08 66 0f eb da 66 0f 70 d1 24 66 0f 76 15 d3 70 01 00 66 0f db 15 ab 70 01 00 66 0f ef da <66> 0f 7f 5e 60 66 0f 6f eb 66 0f 70 cb 4e 66 0f ef cb 66 0f 7f 8e [ 1.100328] RSP: 0018:ffffc900003e7768 EFLAGS: 00010246 [ 1.100728] RAX: ffffc900003e7b48 RBX: ffff88001c702200 RCX: ffff88001cb13850 [ 1.101301] RDX: ffffc900003e7b48 RSI: ffffc900003e7858 RDI: ffff88001cb13860 [ 1.101844] RBP: ffffc900003e7998 R08: ffff88001c79d000 R09: 0000000000000008 [ 1.102409] R10: 0000000000000000 R11: 0000000000000000 R12: ffff88001cb13850 [ 1.102953] R13: 0000000000000000 R14: 0000000000000008 R15: 0000000000000000 [ 1.103518] FS: 0000000000000000(0000) GS:ffff88001ec00000(0000) knlGS:0000000000000000 [ 1.104135] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1.104571] CR2: 00007ffd77dc8ff8 CR3: 000000000220a004 CR4: 00000000003606f0 [ 1.105112] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 1.105650] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 1.106191] Call Trace: [ 1.106384] ? gcmaes_crypt_by_sg+0x14e/0x630 [aesni_intel] [ 1.106817] ? __switch_to_asm+0x34/0x70 [ 1.107122] ? __switch_to_asm+0x40/0x70 [ 1.107421] ? __switch_to_asm+0x40/0x70 [ 1.107726] ? __switch_to_asm+0x40/0x70 [ 1.108029] ? __switch_to_asm+0x40/0x70 [ 1.108332] ? __switch_to_asm+0x40/0x70 [ 1.108637] ? __switch_to_asm+0x34/0x70 [ 1.108944] ? __schedule+0x2ed/0x730 [ 1.109228] ? ttwu_do_wakeup+0x2b/0x170 [ 1.109525] ? activate_task+0x54/0xc0 [ 1.109823] ? schedule+0x3a/0xa0 [ 1.110085] ? ttwu_queue+0x1a0/0x1d0 [ 1.110365] ? __kthread_create_on_node+0x15f/0x1b0 [ 1.110741] gcmaes_encrypt+0x1a9/0x2f0 [aesni_intel] [ 1.111167] ? __crypto_alloc_tfm+0x52/0x170 [ 1.111492] ? __crypto_alloc_tfm+0x13e/0x170 [ 1.111837] ? kzfree+0x31/0x40 [ 1.112100] ? crypto_destroy_tfm+0x56/0x90 [ 1.112431] ? rfc4106_set_hash_subkey+0x6e/0xb0 [aesni_intel] [ 1.112883] ? common_rfc4106_set_key+0x6c/0x90 [aesni_intel] [ 1.113320] helper_rfc4106_encrypt+0x96/0xd0 [aesni_intel] [ 1.113747] gcmaes_wrapper_encrypt+0x6d/0xa0 [aesni_intel] [ 1.114180] __test_aead+0xe60/0x1370 [ 1.114460] test_aead+0x37/0xc0 [ 1.114714] alg_test_aead+0x52/0xb0 [ 1.114994] alg_test+0x12a/0x2e0 [ 1.115253] ? default_wake_function+0x12/0x20 [ 1.115597] ? __wake_up_common+0x8a/0x130 [ 1.115915] ? cryptomgr_probe+0xf0/0xf0 [ 1.116218] ? cryptomgr_probe+0xf0/0xf0 [ 1.116518] cryptomgr_test+0x48/0x50 [ 1.116805] ? cryptomgr_probe+0xf0/0xf0 [ 1.117111] kthread+0x10c/0x150 [ 1.117358] ? kthread_probe_data+0x40/0x40 [ 1.117681] ret_from_fork+0x35/0x40 [ 1.117959] Modules linked in: aesni_intel(+) glue_helper crypto_simd cryptd aes_x86_64 joydev input_leds pcspkr sg i2c_piix4 ext2 ext4 jbd2 virtio_scsi virtio_blk virtio_net net_failover failover virtio_gpu ttm virtio_crypto crypto_$ [ 1.121380] ---[ end trace 18058196474ffa77 ]--- [ 1.121742] RIP: 0010:aesni_gcm_init+0x89/0x30f [aesni_intel] [ 1.122188] Code: 0f 6f ca 66 0f 73 fa 08 66 0f 73 d9 08 66 0f eb da 66 0f 70 d1 24 66 0f 76 15 d3 70 01 00 66 0f db 15 ab 70 01 00 66 0f ef da <66> 0f 7f 5e 60 66 0f 6f eb 66 0f 70 cb 4e 66 0f ef cb 66 0f 7f 8e [ 1.123618] RSP: 0018:ffffc900003e7768 EFLAGS: 00010246 [ 1.124022] RAX: ffffc900003e7b48 RBX: ffff88001c702200 RCX: ffff88001cb13850 [ 1.124564] RDX: ffffc900003e7b48 RSI: ffffc900003e7858 RDI: ffff88001cb13860 [ 1.125112] RBP: ffffc900003e7998 R08: ffff88001c79d000 R09: 0000000000000008 [ 1.125650] R10: 0000000000000000 R11: 0000000000000000 R12: ffff88001cb13850 [ 1.126228] R13: 0000000000000000 R14: 0000000000000008 R15: 0000000000000000 [ 1.126768] FS: 0000000000000000(0000) GS:ffff88001ec00000(0000) knlGS:0000000000000000 [ 1.127411] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1.127855] CR2: 00007ffd77dc8ff8 CR3: 000000000220a004 CR4: 00000000003606f0 [ 1.128396] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 1.128941] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 When creating some init scripts to load during boot the boot fails, log: Aug 21 16:28:40 devnode7 kernel: AVX version of gcm_enc/dec engaged. Aug 21 16:28:40 devnode7 kernel: AES CTR mode by8 optimization enabled Aug 21 16:28:40 devnode7 kernel: general protection fault: 0000 [#1] SMP PTI Aug 21 16:28:40 devnode7 kernel: CPU: 5 PID: 4829 Comm: cryptomgr_test Not tainted 4.18.3-1.el6.elrepo.x86_64 #1 Aug 21 16:28:40 devnode7 kernel: Hardware name: Supermicro SYS-5039MS-H12TRF/X11SSE-F, BIOS 2.1a 03/08/2018 Aug 21 16:28:40 devnode7 kernel: RIP: 0010:aesni_gcm_init+0x89/0x30f [aesni_intel] Aug 21 16:28:40 devnode7 kernel: Code: 0f 6f ca 66 0f 73 fa 08 66 0f 73 d9 08 66 0f eb da 66 0f 70 d1 24 66 0f 76 15 d3 70 01 00 66 0f db 15 ab 70 01 00 66 0f ef da <66> 0f 7f 5e 60 66 0f 6f eb 66 0f 70 cb 4e 66 0f ef cb 66 0f 7f 8e Aug 21 16:28:40 devnode7 kernel: RSP: 0018:ffffc90003997768 EFLAGS: 00010246 Aug 21 16:28:40 devnode7 kernel: RAX: ffffc90003997b48 RBX: ffff8808397cb080 RCX: ffff88084aa52450 Aug 21 16:28:40 devnode7 kernel: RDX: ffffc90003997b48 RSI: ffffc90003997858 RDI: ffff88084aa52460 Aug 21 16:28:40 devnode7 kernel: RBP: ffffc90003997998 R08: ffff88082da18000 R09: 0000000000000008 Aug 21 16:28:40 devnode7 kernel: R10: 0000000000000000 R11: 0000000000000000 R12: ffff88084aa52450 Aug 21 16:28:40 devnode7 kernel: R13: 0000000000000000 R14: 0000000000000008 R15: 0000000000000000 Aug 21 16:28:40 devnode7 kernel: FS: 0000000000000000(0000) GS:ffff880877940000(0000) knlGS:0000000000000000 Aug 21 16:28:40 devnode7 kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 Aug 21 16:28:40 devnode7 kernel: CR2: 00007ffd5b7d7ff8 CR3: 000000000220a005 CR4: 00000000003626e0 Aug 21 16:28:40 devnode7 kernel: DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 Aug 21 16:28:40 devnode7 kernel: DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Aug 21 16:28:40 devnode7 kernel: Call Trace: Aug 21 16:28:40 devnode7 kernel: ? gcmaes_crypt_by_sg+0x14e/0x630 [aesni_intel] Aug 21 16:28:40 devnode7 kernel: ? __switch_to_asm+0x34/0x70 Aug 21 16:28:40 devnode7 kernel: ? __switch_to_asm+0x40/0x70 Aug 21 16:28:40 devnode7 kernel: ? __switch_to_asm+0x40/0x70 Aug 21 16:28:40 devnode7 kernel: ? __switch_to_asm+0x40/0x70 Aug 21 16:28:40 devnode7 kernel: ? __switch_to_asm+0x40/0x70 Aug 21 16:28:40 devnode7 kernel: ? __switch_to_asm+0x40/0x70 Aug 21 16:28:40 devnode7 kernel: ? __switch_to_asm+0x34/0x70 Aug 21 16:28:40 devnode7 kernel: ? __schedule+0x2ed/0x730 Aug 21 16:28:40 devnode7 kernel: ? ttwu_do_wakeup+0x2b/0x170 Aug 21 16:28:40 devnode7 kernel: ? __kthread_create_on_node+0x15f/0x1b0 Aug 21 16:28:40 devnode7 kernel: gcmaes_encrypt+0x1a9/0x2f0 [aesni_intel] Aug 21 16:28:40 devnode7 kernel: ? __crypto_alloc_tfm+0x52/0x170 Aug 21 16:28:40 devnode7 kernel: ? __crypto_alloc_tfm+0x13e/0x170 Aug 21 16:28:40 devnode7 kernel: ? kzfree+0x31/0x40 Aug 21 16:28:40 devnode7 kernel: ? crypto_destroy_tfm+0x56/0x90 Aug 21 16:28:40 devnode7 kernel: ? rfc4106_set_hash_subkey+0x6e/0xb0 [aesni_intel] Aug 21 16:28:40 devnode7 kernel: ? common_rfc4106_set_key+0x6c/0x90 [aesni_intel] Aug 21 16:28:40 devnode7 kernel: helper_rfc4106_encrypt+0x96/0xd0 [aesni_intel] Aug 21 16:28:40 devnode7 kernel: gcmaes_wrapper_encrypt+0x6d/0xa0 [aesni_intel] Aug 21 16:28:40 devnode7 kernel: __test_aead+0xe60/0x1370 Aug 21 16:28:40 devnode7 kernel: test_aead+0x37/0xc0 Aug 21 16:28:40 devnode7 kernel: alg_test_aead+0x52/0xb0 Aug 21 16:28:40 devnode7 kernel: alg_test+0x12a/0x2e0 Aug 21 16:28:40 devnode7 kernel: ? default_wake_function+0x12/0x20 Aug 21 16:28:40 devnode7 kernel: ? __wake_up_common+0x8a/0x130 Aug 21 16:28:40 devnode7 kernel: ? cryptomgr_probe+0xf0/0xf0 Aug 21 16:28:40 devnode7 kernel: ? cryptomgr_probe+0xf0/0xf0 Aug 21 16:28:40 devnode7 kernel: cryptomgr_test+0x48/0x50 Aug 21 16:28:40 devnode7 kernel: ? cryptomgr_probe+0xf0/0xf0 Aug 21 16:28:40 devnode7 kernel: kthread+0x10c/0x150 Aug 21 16:28:40 devnode7 kernel: ? kthread_probe_data+0x40/0x40 Aug 21 16:28:40 devnode7 kernel: ret_from_fork+0x35/0x40 Aug 21 16:28:40 devnode7 kernel: Modules linked in: aesni_intel(+) glue_helper crypto_simd cryptd aes_x86_64 ebtable_nat ebtables iptable_filter ip_tables ip6table_filter ip6_tables ib_ipoib rdma_ucm ib_uverbs ib_umad rdma_cm configfs i$ Aug 21 16:28:40 devnode7 kernel: ---[ end trace bfb36c31a97a956c ]--- Aug 21 16:28:40 devnode7 kernel: RIP: 0010:aesni_gcm_init+0x89/0x30f [aesni_intel] Aug 21 16:28:40 devnode7 kernel: Code: 0f 6f ca 66 0f 73 fa 08 66 0f 73 d9 08 66 0f eb da 66 0f 70 d1 24 66 0f 76 15 d3 70 01 00 66 0f db 15 ab 70 01 00 66 0f ef da <66> 0f 7f 5e 60 66 0f 6f eb 66 0f 70 cb 4e 66 0f ef cb 66 0f 7f 8e Aug 21 16:28:40 devnode7 kernel: RSP: 0018:ffffc90003997768 EFLAGS: 00010246 Aug 21 16:28:40 devnode7 kernel: RAX: ffffc90003997b48 RBX: ffff8808397cb080 RCX: ffff88084aa52450 Aug 21 16:28:40 devnode7 kernel: RDX: ffffc90003997b48 RSI: ffffc90003997858 RDI: ffff88084aa52460 Aug 21 16:28:40 devnode7 kernel: RBP: ffffc90003997998 R08: ffff88082da18000 R09: 0000000000000008 Aug 21 16:28:40 devnode7 kernel: R10: 0000000000000000 R11: 0000000000000000 R12: ffff88084aa52450 Aug 21 16:28:40 devnode7 kernel: R13: 0000000000000000 R14: 0000000000000008 R15: 0000000000000000 Aug 21 16:28:40 devnode7 kernel: FS: 0000000000000000(0000) GS:ffff880877940000(0000) knlGS:0000000000000000 Aug 21 16:28:40 devnode7 kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 Aug 21 16:28:40 devnode7 kernel: CR2: 00007ffd5b7d7ff8 CR3: 000000000220a005 CR4: 00000000003626e0 Aug 21 16:28:40 devnode7 kernel: DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 Aug 21 16:28:40 devnode7 kernel: DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 With aes disabled in the bios, these issues are no longer present.