Messages in this thread | | | Date | Thu, 16 Jun 2011 17:34:42 +0530 | From | Srikar Dronamraju <> | Subject | Re: [PATCH v4 3.0-rc2-tip 13/22] 13: uprobes: Handing int3 and singlestep exception. |
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> > + > > +cleanup_ret: > > + if (u) { > > + down_read(&mm->mmap_sem); > > + if (!set_orig_insn(current, u, probept, true)) > > we try to undo the probe? That doesn't make any sense. I thought you > meant to return to userspace, let it re-take the trap and try again > until you do manage to allocate the user resource.
I meant removing the probe itself https://lkml.org/lkml/2011/4/21/279
We could try reseting and retrying the trap. Just that we might end up looping under memory pressure.
> > This behaviour makes probes totally unreliable under memory pressure.
Under memory pressure we could be unreliable.
> > > + atomic_dec(&mm->uprobes_count); > > + up_read(&mm->mmap_sem); > > + put_uprobe(u); > > + } else { > > + /*TODO Return SIGTRAP signal */ > > + } > > + if (utask) { > > + utask->active_uprobe = NULL; > > + utask->state = UTASK_RUNNING; > > + } > > + set_instruction_pointer(regs, probept); > > +} > > Also, there's a scary amount of TODO in there...
All of those deal with delaying the signals. I am working on it at this moment.
-- Thanks and Regards Srikar
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