Messages in this thread | | | Date | Tue, 15 Jun 2010 11:53:32 +0530 | From | Srikar Dronamraju <> | Subject | Re: [PATCH v5 7/14] x86 support for Uprobes |
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* Christoph Hellwig <hch@infradead.org> [2010-06-14 13:54:23]:
> On Mon, Jun 14, 2010 at 01:59:13PM +0530, Srikar Dronamraju wrote: > > @@ -850,7 +850,19 @@ do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags) > > > > if (thread_info_flags & _TIF_UPROBE) { > > clear_thread_flag(TIF_UPROBE); > > +#ifdef CONFIG_X86_32 > > + /* > > + * On x86_32, do_notify_resume() gets called with > > + * interrupts disabled. Hence enable interrupts if they > > + * are still disabled. > > + */ > > + native_irq_enable(); > > +#endif > > uprobe_notify_resume(regs); > > + > > +#ifdef CONFIG_X86_32 > > + native_irq_disable(); > > +#endif > > I'm no x86 port guru, but this looks rather worriesome to me. Why does > do_notify_resume have different calling conventions on 32 vs 64-bit? > And if there is a good reason that 32-bit has them disabled, why is > enabling them in the middle of do_notify_resume okay?
Thanks for bringing this up. I have no idea about why do_notify_resume() gets called with interrupts disabled in 32 bit. I would be happy to know the reason and rework based on inputs. I did query a few people about this but I havent got an answer on why we they are disabled on 32 bit and if its Okay to enable at this place.
Ingo, Is there any person whom I could check with to get to know why the interrupts are disabled on x86_32?
> > > +void arch_uprobe_disable_sstep(struct pt_regs *regs) > > +{ > > + /* Disable single-stepping by clearing what we set */ > > + clear_thread_flag(TIF_SINGLESTEP); > > + clear_thread_flag(TIF_FORCED_TF); > > + regs->flags &= ~X86_EFLAGS_TF; > > +} > > This seems to have one layer of indentation too much.
Okay, I shall fix this in the next iteration.
-- Thanks and Regards Srikar
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