Steps to reproduce:

	modprobe tcrypt		# with CONFIG_DEBUG_SG=y

testing cts(cbc(aes)) encryption
test 1 (128 bit key):
------------[ cut here ]------------
kernel BUG at include/linux/scatterlist.h:65!
invalid opcode: 0000 [1] PREEMPT SMP DEBUG_PAGEALLOC
CPU 0 
Modules linked in: tea xts twofish twofish_common tcrypt(+) [maaaany]
Pid: 16151, comm: modprobe Not tainted 2.6.26-rc4-fat #7
RIP: 0010:[<ffffffffa0bf032e>]  [<ffffffffa0bf032e>] :cts:cts_cbc_encrypt+0x151/0x355
RSP: 0018:ffff81016f497a88  EFLAGS: 00010286
RAX: ffffe20009535d58 RBX: ffff81016f497af0 RCX: 0000000087654321
RDX: ffff8100010d4f28 RSI: ffff81016f497ee8 RDI: ffff81016f497ac0
RBP: ffff81016f497c38 R08: 0000000000000000 R09: 0000000000000011
R10: ffffffff00000008 R11: ffff8100010d4f28 R12: ffff81016f497ac0
R13: ffff81016f497b30 R14: 0000000000000010 R15: 0000000000000010
FS:  00007fac6fa276f0(0000) GS:ffffffff8060e000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 00007f12ca7cc000 CR3: 000000016f441000 CR4: 00000000000026e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff4ff0 DR7: 0000000000000400
Process modprobe (pid: 16151, threadinfo ffff81016f496000, task ffff8101755b4ae0)
Stack:  0000000000000001 ffff81016f496000 ffffffff80719f78 0000000000000001
 0000000000000001 ffffffff8020c87c ffff81016f99c918 20646c756f772049
 65687420656b696c 0000000000000020 0000000000000000 0000000033341102
Call Trace:
 [<ffffffff8020c87c>] ? restore_args+0x0/0x30
 [<ffffffffa04aa311>] ? :aes_generic:crypto_aes_expand_key+0x311/0x369
 [<ffffffff802ab453>] ? check_object+0x15a/0x213
 [<ffffffff802aad22>] ? init_object+0x6e/0x76
 [<ffffffff802ac3ae>] ? __slab_free+0xfc/0x371
 [<ffffffffa0bf05ed>] :cts:crypto_cts_encrypt+0xbb/0xca
 [<ffffffffa07108de>] ? :crypto_blkcipher:setkey+0xc7/0xec
 [<ffffffffa07110b8>] :crypto_blkcipher:async_encrypt+0x38/0x3a
 [<ffffffffa2ce9341>] :tcrypt:test_cipher+0x261/0x7c6
 [<ffffffffa2cfd9df>] :tcrypt:tcrypt_mod_init+0x9df/0x1b30
 [<ffffffff80261e35>] sys_init_module+0x9e/0x1b2
 [<ffffffff8020c15a>] system_call_after_swapgs+0x8a/0x8f
Code: 45 c0 e8 aa 24 63 df 48 c1 e8 0c 48 b9 00 00 00 00 00 e2 ff ff 48 8b 55 88 48 6b c0 68 48 01 c8 b9 21 43 65 87 48 39 4d 80 74 04 <0f> 0b eb fe f6 c2 01 74 04 0f 0b eb fe 83 e2 03 4c 89 ef 44 89 
RIP  [<ffffffffa0bf032e>] :cts:cts_cbc_encrypt+0x151/0x355
 RSP <ffff81016f497a88>
---[ end trace e8bahiarjand37fd ]---

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>