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Date: Tue, 8 Jan 2013 19:13:03 +0100 From: Oleg Nesterov <oleg@...hat.com> To: Srikar Dronamraju <srikar@...ux.vnet.ibm.com> Cc: Ingo Molnar <mingo@...e.hu>, Peter Zijlstra <peterz@...radead.org>, Ananth N Mavinakayanahalli <ananth@...ibm.com>, Anton Arapov <anton@...hat.com>, Frank Eigler <fche@...hat.com>, Josh Stone <jistone@...hat.com>, "Suzuki K. Poulose" <suzuki@...ibm.com>, linux-kernel@...r.kernel.org Subject: Re: [PATCH 6/7] uprobes: Do not allocate current->utask unnecessary On 01/08, Srikar Dronamraju wrote: > > * Oleg Nesterov <oleg@...hat.com> [2012-12-31 18:52:29]: > > > static void handle_swbp(struct pt_regs *regs) > > { > > - struct uprobe_task *utask; > > struct uprobe *uprobe; > > unsigned long bp_vaddr; > > int uninitialized_var(is_swbp); > > @@ -1512,19 +1515,12 @@ static void handle_swbp(struct pt_regs *regs) > > if (unlikely(!test_bit(UPROBE_COPY_INSN, &uprobe->flags))) > > goto out; > > > > - utask = get_utask(); > > - if (!utask) > > - goto out; /* re-execute the instruction. */ > > - > > If get_utask fails with the above change, Dont we end up calling > handler_chain twice(or more)?. After restart, yes. > I think this is probably true with > previous patch too. And this can happen with the current code too, if xol_alloc_area() fails. So I think this is probably fine. Besides, if GFP_KERNEL fails the task should be oom-killed in practice. Oleg. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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