Re: WARNING: kernel stack regs has bad 'bp' value (2)

From: Eric Biggers
Date: Thu Nov 30 2017 - 04:17:36 EST


On Tue, Nov 28, 2017 at 10:36:01AM -0800, syzbot wrote:
> WARNING: kernel stack regs at ffff8801c1e5f468 in syzkaller196611:6199 has
> bad 'bp' value 0000000000000001
> unwind stack type:0 next_sp: (null) mask:0x6 graph_idx:0
> ffff8801db4075a8: ffff8801db407630 (0xffff8801db407630)
> ffff8801db4075b0: ffffffff8128a84e (__save_stack_trace+0x6e/0xd0)
> ffff8801db4075b8: 0000000000000000 ...
> ffff8801db4075c0: ffff8801c1e58000 (0xffff8801c1e58000)
> ffff8801db4075c8: ffff8801c1e60000 (0xffff8801c1e60000)
> ffff8801db4075d0: 0000000000000000 ...
> ffff8801db4075d8: 0000000000000006 (0x6)
> ffff8801db4075e0: ffff8801c1e4e000 (0xffff8801c1e4e000)
> ffff8801db4075e8: 0000010100000000 (0x10100000000)
> ffff8801db4075f0: 0000000000000000 ...
> ffff8801db4075f8: ffff8801db4075a8 (0xffff8801db4075a8)
> ffff8801db407600: ffffffff8134ff7d (__twofish_enc_blk_3way+0x1b1d/0x1b30)

Looks like the x86_64 "3 way" version of Twofish (twofish-x86_64-asm_64-3way.S)
needs to be updated to not use %rbp.

Eric