Messages in this thread | | | Date | Fri, 1 Jul 2011 17:06:26 +0530 | From | Ananth N Mavinakayanahalli <> | Subject | Re: [BUG] kprobes crashing because of preempt count |
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On Fri, Jul 01, 2011 at 10:12:03AM +0900, Masami Hiramatsu wrote: > (2011/06/30 22:23), Steven Rostedt wrote:
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> > Do we really need to have preemption disabled throughout this? Is it > > because we don't want to migrate or call schedule? Not sure what the > > best way to fix this is. Perhaps we add a kprobe_preempt_disable() that > > is checked as well? > > I think the best way to do that is just removing preemption disabling > code, because > - breakpoint exception itself disables interrupt (at least on x86) > - While single stepping, interrupts also be disabled.
On 64-bit powerpc, kprobe handlers are run with interrupts enabled (MSR_EE = 1), but most instructions (including loads/stores) are emulated, so for the most part, we don't take the sstep exception.
Ananth
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