Re: [patch] i386: another possible singlestep fix

[Linus Torvalds]

On Fri, 17 Feb 2006, Chuck Ebbert wrote:
>
> When entering kernel via int80, TIF_SINGLESTEP is not set
> when TF has been set in eflags by the user.  This patch
> does that.

This really shouldn't matter.

When we enter the kernel through "int 0x80", we don't need to do anything 
about TIF_SINGLESTEP, because unlike the "sysenter" path, the "int" 
instruction will automatically do the right thing (save old eflags on the 
stack).

So afaik, this won't actually do anything (except make _the_ most 
timing-critical path in the kernel slower). Have you actually seen any 
effects of it?

		Linus
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