Re: [PATCH 1/7] uprobes/x86: Only rep+nop can be emulated correctly

From: Srikar Dronamraju
Date: Sat Oct 06 2012 - 03:20:04 EST


* Oleg Nesterov <oleg@xxxxxxxxxx> [2012-09-30 21:41:58]:

> __skip_sstep() correctly detects the "nontrivial" nop insns,
> but since it doesn't update regs->ip we can not really skip
> "0x0f 0x1f | 0x0f 0x19 | 0x87 0xc0", the probed application
> is killed by SIGILL'ed handle_swbp().
>
> Remove these additional checks. If we want to implement this
> correctly we need to know the full insn length to update ->ip.
>
> rep* + nop is fine even without updating ->ip.
>
> Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
> ---

Acked-by: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>

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