Messages in this thread | | | Date | Thu, 2 Aug 2012 19:53:12 +0200 | From | Oleg Nesterov <> | Subject | Re: [PATCH] uprobes: Ignore unsupported instructions in uprobe_mmap |
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On 08/02, Srikar Dronamraju wrote: > > * Oleg Nesterov <oleg@redhat.com> [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) > > > if (ret == -EEXIST) { > > > ret = 0; > > > > > > - if (!is_swbp_at_addr(vma->vm_mm, vaddr)) > > > + if (!is_swbp_at_addr(vma->vm_mm, vaddr)) { > > > + put_uprobe(uprobe); > > > continue; > > > + } > > > > Yes, this part looks correct. > > > > In fact, I think this is not really correct anyway (wrt counter) > > but we are going to kill it. > > > > > > Are you expecting the counter to be decreased/increased here?
uprobes_state.count is very wrong, afaics. I'll try to send the fixes "soon", after we solve the pending problems (this one + stepping).
> 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 consumers.
Yes, exactly, and this case doesn't look 100% right too,
> i.e there are no uprobe->consumers and the underlying > instruction is still not a breakpoint instruction.
Yes, but what if it _IS_ "int3" ?
Yet another reason to move arch_uprobe_analyze_insn/etc to _register.
Oleg.
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