On 08/03, Srikar Dronamraju wrote:
>
> * Oleg Nesterov [2012-08-02 19:53:12]:
>
> > On 08/02, Srikar Dronamraju wrote:
> > >
> > > This is case where the uprobe_mmap() and uprobe_unregister() raced, and
> > > by the time install_breakpoint() was called by uprobe_mmap(), there were
> > > no consume
On 08/03, Srikar Dronamraju wrote:
>
> > But mmap_region() is worse, much worse. It simply can _not_ fail
> > after uprobe_mmap (of course, I am not saying this is unfixable)
> > without the crash. And note that the crash is "delayed". And btw,
> > like dup_mmap(), mmap_region() doesn't return the
> OK, lets start with dup_mmap:
>
> // retval == 0
>
> if (file && uprobe_mmap(tmp))
> goto out;
>
> out:
> up_write(&mm->mmap_sem);
> flush_tlb_mm(oldmm);
> up_write(&oldmm->mmap_sem);
>
* Oleg Nesterov [2012-08-02 19:53:12]:
> On 08/02, Srikar Dronamraju wrote:
> >
> > * Oleg Nesterov [2012-08-02 16:17:57]:
> >
> > > Forgot to mention...
> > >
> > > On 08/02, Srikar Dronamraju wrote:
> > > >
> > > > While at it, add a missing put_uprobe() in the path where uprobe_mmap()
> > > >
On 08/02, Srikar Dronamraju wrote:
>
> * Oleg Nesterov [2012-08-02 16:17:57]:
>
> > Forgot to mention...
> >
> > On 08/02, Srikar Dronamraju wrote:
> > >
> > > While at it, add a missing put_uprobe() in the path where uprobe_mmap()
> > > races with uprobe_unregister().
> > > ...
> > > @@ -1051,8 +
On 08/02, Srikar Dronamraju wrote:
>
> How about having your fix + my patch to fix the uprobe_mmap()?
(I guess you mean -ENOTSUPP part)
Perhaps...
But, as I said, I think that until we fix the callers uprobe_mmap()
should ignore all errors and proceed. Except, perhaps, it makes sense
to check fa
* Oleg Nesterov [2012-08-02 16:17:57]:
> Forgot to mention...
>
> On 08/02, Srikar Dronamraju wrote:
> >
> > While at it, add a missing put_uprobe() in the path where uprobe_mmap()
> > races with uprobe_unregister().
> > ...
> > @@ -1051,8 +1051,10 @@ int uprobe_mmap(struct vm_area_struct *vma)
> > uprobe_mmap()->install_breakpoint() can fail if the probed insn is not
> > supported
>
> But there are other reasons why it can fail,
>
> > However failing mmap_region()/do_fork() because of a probe on an
> > unsupported instruction is wrong.
>
> Srikar, I strongly, absolutely disagree. Plea
Forgot to mention...
On 08/02, Srikar Dronamraju wrote:
>
> While at it, add a missing put_uprobe() in the path where uprobe_mmap()
> races with uprobe_unregister().
> ...
> @@ -1051,8 +1051,10 @@ int uprobe_mmap(struct vm_area_struct *vma)
> if (ret == -EEXIST) {
>
On 08/02, Srikar Dronamraju wrote:
>
> uprobe_mmap()->install_breakpoint() can fail if the probed insn is not
> supported
But there are other reasons why it can fail,
> However failing mmap_region()/do_fork() because of a probe on an
> unsupported instruction is wrong.
Srikar, I strongly, absolu
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