On 11/22, Oleg Nesterov wrote:
> On 11/22, Andrea Parri wrote:
> >
> > Commit 142b18ddc8143 ("uprobes: Fix handle_swbp() vs unregister() +
> > register() race") added the UPROBE_COPY_INSN flag, and corresponding
> > smp_wmb() and smp_rmb() memory barriers, to ensure that handle_swbp()
> > uses fully-initialized uprobes only.
> >
> > However, the smp_rmb() is mis-placed: this barrier should be placed
> > after handle_swbp() has tested for the flag, thus guaranteeing that
> > (program-order) subsequent loads from the uprobe can see the initial
> > stores performed by prepare_uprobe().
> >
> > Move the smp_rmb() accordingly. Also amend the comments associated
> > to the two memory barriers to indicate their actual locations.
> >
> > Signed-off-by: Andrea Parri <[email protected]>
> > Cc: Peter Zijlstra <[email protected]>
> > Cc: Ingo Molnar <[email protected]>
> > Cc: Arnaldo Carvalho de Melo <[email protected]>
> > Cc: Alexander Shishkin <[email protected]>
> > Cc: Jiri Olsa <[email protected]>
> > Cc: Namhyung Kim <[email protected]>
> > Cc: Oleg Nesterov <[email protected]>
> > Cc: [email protected]
> > Fixes: 142b18ddc8143 ("uprobes: Fix handle_swbp() vs unregister() +
> > register() race")
>
> Thanks,
>
> Acked-by: Oleg Nesterov <[email protected]>
Yes, but I am not sure this is the -stable material...
Oleg.
