Re: [PATCH] uprobes: don't enable/disable signle step if the userdid it

[Ananth N Mavinakayanahalli]

On Thu, Jul 26, 2012 at 05:20:43PM +0200, Sebastian Andrzej Siewior wrote:
> If someone is using single stepping over uprobe brackpoint then after
> we pass the uprobe single step, single stepping is disabled and the user
> who enebaled them in the first place does not know anything about this.
> 
> This patch avoids enabling / disabling the single step mode if it is
> already enabled.

This could happen any time 2 different entities call the
user_(en/dis)able_single_step() helpers on the same thread.

Wouldn't the right way to fix it be to teach these helpers
to honor what the TIF_SINGLESTEP flag setting was in the first place?
This way you'd get rid of the portability concerns too, since these
helpers are available on most architectures.

Ananth

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