Messages in this thread | | | Subject | Re: [PATCH v5 3.1.0-rc4-tip 17/26] x86: arch specific hooks for pre/post singlestep handling. | From | Peter Zijlstra <> | Date | Tue, 27 Sep 2011 13:44:12 +0200 |
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On Mon, 2011-09-26 at 22:04 +0530, Srikar Dronamraju wrote: > * Peter Zijlstra <peterz@infradead.org> [2011-09-26 16:23:53]: > > > On Tue, 2011-09-20 at 17:33 +0530, Srikar Dronamraju wrote: > > > +fail: > > > + pr_warn_once("uprobes: Failed to adjust return address after" > > > + " single-stepping call instruction;" > > > + " pid=%d, sp=%#lx\n", current->pid, sp); > > > + return -EFAULT; > > > > So how can that happen? Single-Step while someone unmapped the stack? > > We do a copy_to_user, copy_from_user just above this,
I saw that,
> Now if either of > them fail, we have no choice but to Bail out.
Agreed,
> What caused this EFault may not be under Uprobes's Control.
I never said it was.. All I asked is what (outside of uprobe) was done to cause this, and why is this particular error important enough to warrant a warn.
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