FYI, we noticed the below changes on https://git.kernel.org/pub/scm/linux/kernel/git/s390/linux.git features commit 420ce36f0515c0fe8b5fda9420bb64cfbea75841 ("crypto/xor: skip speed test if the xor function is selected automatically") [ 4.830567] .................................... done. [ 4.834798] page_owner is disabled [ 4.839879] raid6test: testing the 4-disk case... [ 4.841076] BUG: unable to handle kernel NULL pointer dereference at 0000000000000020 [ 4.843396] IP: [] xor_blocks+0x2e/0x4b [ 4.844877] PGD 0 [ 4.845705] Oops: 0000 [#1] SMP [ 4.846892] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.5.0-rc5-00005-g420ce36 #1 [ 4.848684] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014 [ 4.850461] task: ffff880012a38000 ti: ffff880012a40000 task.ti: ffff880012a40000 [ 4.852142] RIP: 0010:[] [] xor_blocks+0x2e/0x4b [ 4.854341] RSP: 0000:ffff880012a43bc8 EFLAGS: 00010246 [ 4.855674] RAX: 0000000000000000 RBX: ffffffff82d943e0 RCX: ffff88000e6f7000 [ 4.857367] RDX: ffff88000e6f6000 RSI: ffff88000e710000 RDI: 0000000000001000 [ 4.859058] RBP: ffff880012a43bc8 R08: 0000000000000002 R09: ffffffff82d943e0 [ 4.860705] R10: 0000000000000002 R11: 0000000000000001 R12: 0000000000000004 [ 4.862376] R13: ffff880012a43cf8 R14: 0000000000000002 R15: 0000000000000002 [ 4.864169] FS: 0000000000000000(0000) GS:ffff880013800000(0000) knlGS:0000000000000000 [ 4.866144] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 4.867564] CR2: 0000000000000020 CR3: 0000000001d40000 CR4: 00000000000406b0 [ 4.869247] Stack: [ 4.873291] ffff880012a43c30 ffffffff8139c981 0000000000000000 ffffffff82d943e8 [ 4.875322] 0000000000000002 0000000000001000 0000000000000002 ffff88000e710000 [ 4.877246] ffff880013040400 0000000000000004 ffff880012a43cf4 ffff880012a43cf8 [ 4.879384] Call Trace: [ 4.880174] [] async_xor+0x1b1/0x1da [ 4.881392] [] async_syndrome_val+0x16f/0x357 [ 4.882849] [] ? raid6_test_exit+0x6/0x6 [ 4.884340] [] raid6_dual_recov+0x269/0x2c8 [ 4.885847] [] test+0x2dc/0x4f1 [ 4.886970] [] ? raid6_test_exit+0x6/0x6 [ 4.888221] [] raid6_test+0x72/0x119 [ 4.889464] [] ? test+0x4f1/0x4f1 [ 4.890646] [] do_one_initcall+0x10c/0x1c7 [ 4.891943] [] kernel_init_freeable+0x113/0x199 [ 4.893392] [] ? rest_init+0x136/0x136 [ 4.894743] [] kernel_init+0x9/0xcf [ 4.895938] [] ret_from_fork+0x3f/0x70 [ 4.897148] [] ? rest_init+0x136/0x136 [ 4.898402] Code: fa 48 8b 05 72 7d 9f 01 41 83 fa 01 89 f7 48 89 d6 48 89 e5 48 8b 11 75 05 ff 50 18 eb 28 41 83 fa 02 49 89 c9 48 8b 49 08 75 05 50 20 eb 16 41 83 fa 03 4d 8b 41 10 75 05 ff 50 28 eb 07 4d [ 4.911424] RIP [] xor_blocks+0x2e/0x4b [ 4.912791] RSP [ 4.913792] CR2: 0000000000000020 [ 4.914654] ---[ end trace 596e7e91d3b9c992 ]--- [ 4.915786] Kernel panic - not syncing: Fatal exception Thanks, Kernel Test Robot