linux-kernel - Re: Serial related oops

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 21 Feb 2007 21:57:50 -0800
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Jose Goncalves <jose.goncalves@...v.pt>,
	Frederik Deweerdt <deweerdt@...e.fr>,
	akpm@...ux-foundation.org, linux-kernel@...r.kernel.org
Subject: Re: Serial related oops

Russell King wrote:

> 
> Plainly, %ebx changed across the call to serial_in() at c01c0f7b.
> First thing to notice is this violates the C code - "up" can not
> change.
> 
> Now let's look at serial_in:
> 
> c01bfa70:       55                      push   %ebp
> c01bfa71:       89 e5                   mov    %esp,%ebp
> c01bfa73:       53                      push   %ebx
> ...
> c01bfab7:       5b                      pop    %ebx
> c01bfab8:       5d                      pop    %ebp
> c01bfab9:       c3                      ret
> 
> This code tells the CPU to preserves %ebx and %ebp.  But we know %ebx
> _wasn't_ preserved.  Ergo, your CPU is plainly not doing what the code
> told it to do.
> 

... assuming nothing else clobbered the stack slot (which would be a 
compiler error, or a wild pointer.)

Got a disassembly of the whole function?

	-hpa
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/