Re: [uml-devel] Re: [RFC] PATCH 3/4 - Time virtualization : PTRACE_SYSCALL_MASK

[Jeff Dike]

On Thu, Apr 20, 2006 at 04:17:28PM +0200, Bodo Stroesser wrote:
> Shouldn't 'len' better be the number of bits in the mask than the number of 
> chars?

Yup.

> OTOH, I think UML shouldn't send the entire mask, but relevant part only. 
> The missing end is filled with 0xff by host anyway. So it would be
> enough to send the mask up to the highest bit representing a
> syscall, that needs to be executed by host.  (currently, that is
> __NR_gettimeofday). If UML would do so, no more problem results from
> UML having a higher NR_syscall than the host (as long as the new
> syscalls are to be intercepted and executed by UML)

Yup, that was part of the intent of sending in the mask length.

> A greater problem might be a process in UML, that calls an invalid syscall 
> number. AFAICS syscall number (orig_eax) isn't checked before it is
> used in do_syscall_trace to address syscall_mask. This might result
> in a crash. 

Yeah, this needs fixing.

				Heff
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