Messages in this thread | | | Date | Mon, 18 Jun 2012 17:38:31 +0530 | From | Srikar Dronamraju <> | Subject | Re: [PATCH 11/15] uprobes: move BUG_ON(UPROBE_SWBP_INSN_SIZE) from write_opcode() to install_breakpoint() |
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* Oleg Nesterov <oleg@redhat.com> [2012-06-15 19:52:48]:
> On 06/15, Srikar Dronamraju wrote: > > > > > @@ -699,6 +694,10 @@ install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, > > > if (ret) > > > return ret; > > > > > > + /* write_opcode() assumes we don't cross page boundary */ > > > + BUG_ON((uprobe->offset & ~PAGE_MASK) + > > > + UPROBE_SWBP_INSN_SIZE > PAGE_SIZE); > > > + > > > uprobe->flags |= UPROBE_COPY_INSN; > > > } > > > > I am now thinking if we really need a BUG_ON? > > I was thinking about this too. > > > I am now thinking I should > > have had a check at the start in uprobe_register() and failed the request. > > > > Something like > > if ((offset & ~PAGE_MASK) + UPROBE_SWBP_INSN_SIZE > PAGE_SIZE) > > return -EINVAL; > > Perhaps. Or we can simply remove it. arch_uprobe_analyze_insn() > should be careful anyway, and all this validation should be moved > into uprobe_register/alloc_uprobe. > > I do not really mind, I only wanted to simplify write_opcode() which > does a lot of unnecessary things (say, lock_page, I am going to kill > it). > > So. Do you want me to redo this patch? Or do you think we can keep > this "must not happen after arch_uprobe_analyze_insn" check? >
No, I will just fix it up later.
-- Thanks and Regards Srikar
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