Messages in this thread | | | Date | Tue, 25 Apr 2006 14:32:51 -0400 | From | Jeff Dike <> | Subject | Re: [uml-devel] Re: [RFC] PATCH 3/4 - Time virtualization : PTRACE_SYSCALL_MASK |
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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.
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