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Date: Thu, 29 Jul 2010 10:49:50 +0800 From: DDD <dongdong.deng@...driver.com> To: Frederic Weisbecker <fweisbec@...il.com> CC: Jason Wessel <jason.wessel@...driver.com>, kgdb-bugreport@...ts.sourceforge.net, Linus Torvalds <torvalds@...ux-foundation.org>, linux-kernel@...r.kernel.org Subject: Re: [Kgdb-bugreport] [GIT PULL] kgdb regression fixes for 2.6.35-rc5 Frederic Weisbecker wrote: > On Wed, Jul 28, 2010 at 07:14:42PM -0500, Jason Wessel wrote: >> On 07/28/2010 04:26 PM, Linus Torvalds wrote: >>> On Wed, Jul 28, 2010 at 2:17 PM, Frederic Weisbecker <fweisbec@...il.com> wrote: >>>> I'm sorry I spot it a bit late. >>>> There is a little issue in this patch, irqs won't >>>> be restored: >>>> >>>> @@ -588,9 +588,10 @@ int kgdb_ll_trap(int cmd, const char *str, >>>> if (!kgdb_io_module_registered) >>>> return NOTIFY_DONE; >>>> >>>> + local_irq_save(flags); >>>> return __kgdb_notify(&args, cmd); >>>> + local_irq_restore(flags); >>>> } >>> Yeah, that's obviously crap. I also wonder why __kgdb_notify messes up >>> the flags to begin with. >>> >> This should not be needed as the irqs should already be off while in the overflow handler. > > > > Interrupts are not disabled in the debug exception handler. Hi Frederic, The debug was initialized as an intr gate, thus the interrupts have been disabled in the debug exception handler. :-) arch/x86/kernel/traps.c: 820 /* Set of traps needed for early debugging. */ 821 void __init early_trap_init(void) 822 { 823 set_intr_gate_ist(1, &debug, DEBUG_STACK); 824 /* int3 can be called from all */ 825 set_system_intr_gate_ist(3, &int3, DEBUG_STACK); 826 set_intr_gate(14, &page_fault); 827 load_idt(&idt_descr); 828 } Thanks, Dongdong > > I'm not sure what would be the state of dr6 if a nested debug exception > would happen while do_debug() is interrupted. > > Perhaps the previous dr6 value is dropped. Intel manuals don't seem to say anything > about that. > > Anyway that's a separate issue. The current patch fixes a regression and > it looks good. > > Thanks. > > > ------------------------------------------------------------------------------ > The Palm PDK Hot Apps Program offers developers who use the > Plug-In Development Kit to bring their C/C++ apps to Palm for a share > of $1 Million in cash or HP Products. Visit us here for more details: > http://p.sf.net/sfu/dev2dev-palm > _______________________________________________ > Kgdb-bugreport mailing list > Kgdb-bugreport@...ts.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/kgdb-bugreport > -- 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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