Hi There is a bug in mcryptd initialization. This is a test module that tries various hash algorithms. When you load the module with "insmod test.ko 'alg=mcryptd(md5)'", the machine crashes. Mikulas #include <linux/module.h> #include <linux/init.h> #include <crypto/hash.h> static char *alg = "md5"; module_param_named(alg, alg, charp, 0444); MODULE_PARM_DESC(alg, "the algorith to test"); static bool sync = true; module_param_named(sync, sync, bool, 0444); MODULE_PARM_DESC(alg, "sync flag"); static int __init dump_init(void) { struct crypto_shash *h; char key[4]; int r; printk("testing algorithm '%s'\n", alg); h = crypto_alloc_shash(alg, 0, sync ? CRYPTO_ALG_ASYNC : 0); if (IS_ERR(h)) { printk("error %d\n", (int)PTR_ERR(h)); return PTR_ERR(h); } printk("setting key\n"); r = crypto_shash_setkey(h, key, sizeof key); if (r) printk("setkey: %d\n", r); crypto_free_shash(h); printk("module loaded\n"); return 0; } static void __exit dump_exit(void) { printk("dump exit\n"); } module_init(dump_init) module_exit(dump_exit) MODULE_LICENSE("GPL"); [898029.802035] BUG: unable to handle kernel NULL pointer dereference at (null) [898029.806060] IP: [<ffffffffa022014d>] md5_final+0xad/0x210 [md5] [898029.808156] PGD 11a5d8067 [898029.809051] PUD 11a491067 PMD 0 [898029.810280] [898029.810904] Oops: 0002 [#1] PREEMPT SMP [898029.812239] Modules linked in: md5 testdump(O+) mcryptd uvesafb cfbfillrect cfbimgblt cn cfbcopyarea fbcon bitblit fbcon_rotate fbcon_ccw fbcon_ud fbcon_cw softcursor fb fbdev font ipv6 binfmt_misc mousedev af_packet psmouse pcspkr virtio_net virtio_balloon button ext4 crc16 jbd2 mbcache dm_mod virtio_blk evdev virtio_pci virtio_ring virtio [898029.817178] CPU: 9 PID: 187 Comm: kworker/9:1 Tainted: G O 4.9.0-rc7+ #6 [898029.818066] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 [898029.818732] Workqueue: crypto mcryptd_queue_worker [mcryptd] [898029.819394] task: ffff88011aa2bd80 task.stack: ffff880118480000 [898029.820077] RIP: 0010:[<ffffffffa022014d>] [<ffffffffa022014d>] md5_final+0xad/0x210 [md5] [898029.821050] RSP: 0018:ffff880118483d48 EFLAGS: 00010286 [898029.821661] RAX: 04b2008fd98c1dd4 RBX: ffff880119cd7f28 RCX: 00000000980980e9 [898029.822464] RDX: 7e42f8ec980980e9 RSI: 00000000ef1c4f74 RDI: ffff880119cd7f30 [898029.823293] RBP: ffff880118483d68 R08: 000000001b99d513 R09: 0000000000000000 [898029.824117] R10: 0000000000000000 R11: 00000000b8b56373 R12: ffff880119cd7f18 [898029.824944] R13: 0000000000000000 R14: ffff880119cd7f38 R15: ffffffffa01ee43c [898029.825776] FS: 0000000000000000(0000) GS:ffff88011fd20000(0000) knlGS:0000000000000000 [898029.826712] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [898029.827376] CR2: 0000000000000000 CR3: 000000011a6c9000 CR4: 00000000000006a0 [898029.828204] Stack: [898029.828452] ffff880119cd7f18 ffff88011fd3bb00 0000000000000000 ffff880119cd7e00 [898029.829351] ffff880118483da0 ffffffff8119f281 ffff880119cd7f18 ffff88011fd3bb00 [898029.830242] ffff88011fd3bae0 ffff880119cd7e00 ffffffffa01ee43c ffff880119cd7ec8 [898029.831141] Call Trace: [898029.831460] [<ffffffff8119f281>] ? crypto_shash_final+0x31/0xb0 [898029.832151] [<ffffffffa01ee43c>] ? mcryptd_queue_worker+0x1c/0x190 [mcryptd] [898029.832980] [<ffffffff8119f743>] ? shash_ahash_finup+0x73/0x80 [898029.833672] [<ffffffff81016a5f>] ? __switch_to+0x27f/0x460 [898029.834305] [<ffffffffa01eeabf>] ? mcryptd_hash_digest+0x4f/0x80 [mcryptd] [898029.835125] [<ffffffffa01ee467>] ? mcryptd_queue_worker+0x47/0x190 [mcryptd] [898029.835963] [<ffffffff8105974f>] ? process_one_work+0x1bf/0x3f0 [898029.836681] [<ffffffff810599c2>] ? worker_thread+0x42/0x4c0 [898029.837362] [<ffffffff81059980>] ? process_one_work+0x3f0/0x3f0 [898029.838045] [<ffffffff81059980>] ? process_one_work+0x3f0/0x3f0 [898029.838739] [<ffffffff8105ea49>] ? kthread+0xb9/0xd0 [898029.839318] [<ffffffff8105e990>] ? kthread_park+0x70/0x70 [898029.839959] [<ffffffff8131b965>] ? ret_from_fork+0x25/0x30 [898029.840594] Code: 14 c5 00 00 00 00 48 c1 e8 1d 41 89 44 24 5c 41 89 54 24 58 e8 45 ea 0e e1 49 8b 44 24 10 49 8b 54 24 18 48 8d 7b 08 48 83 e7 f8 <49> 89 45 00 49 89 55 08 31 c0 49 c7 44 24 10 00 00 00 00 48 c7 [898029.843633] RIP [<ffffffffa022014d>] md5_final+0xad/0x210 [md5] [898029.844354] RSP <ffff880118483d48> [898029.844769] CR2: 0000000000000000 [898029.845166] ---[ end trace 2ecde0bf66717337 ]--- -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel