Messages in this thread Patch in this message | | | Date | Tue, 12 Sep 2006 09:50:47 +0200 | From | Ingo Molnar <> | Subject | [patch] genirq/MSI: restore __do_IRQ() compat logic temporarily |
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* Eric W. Biederman <ebiederm@xmission.com> wrote:
> Ok. Looking at it I almost certain the problem is that > we lost the hunk of code removed in: 266f0566761cf88906d634727b3d9fc2556f5cbd > i386: Fix stack switching in do_IRQ > > - if (!irq_desc[irq].handle_irq) { > - __do_IRQ(irq, regs); > - goto out_exit; > - } > > The msi code does not yet set desc->handle_irq. So when we attempt to > call it we get a NULL pointer dereference.
indeed ... We thought the MSI cleanup went all the way with the irqchips conversion, that's we suggested to Andrew to drop this chunk in -mm too.
> Except for adding that hunk back in and breaking 4K stacks I don't > have an immediate fix.
i've attached a bandaid patch for -mm below. Brandon, does this solve the crash you are seeing?
> I do have a pending cleanup that should result in us setting > handle_irq in all cases. I will see if I can advance that shortly.
yeah, that's the right solution.
Ingo
------------------> Subject: [patch] genirq/MSI: restore __do_IRQ() compat logic temporarily From: Ingo Molnar <mingo@elte.hu>
restore the __do_IRQ() compat logic temporarily, until the MSI genirq conversion has been completed.
disable 4KSTACKS temporarily too.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
--- arch/i386/Kconfig.debug | 4 ++++ arch/i386/kernel/irq.c | 5 +++++ 2 files changed, 9 insertions(+)
Index: linux-2.6.18-rc6-mm1/arch/i386/Kconfig.debug =================================================================== --- linux-2.6.18-rc6-mm1.orig/arch/i386/Kconfig.debug +++ linux-2.6.18-rc6-mm1/arch/i386/Kconfig.debug @@ -56,8 +56,12 @@ config DEBUG_RODATA portion of the kernel code won't be covered by a 2MB TLB anymore. If in doubt, say "N". +# +# FIXME: Disabled temporarily until the MSI genirq conversion is done! +# config 4KSTACKS bool "Use 4Kb + 4Kb for kernel stacks instead of 8Kb" if DEBUG_KERNEL + depends on n default y help If you say Y here the kernel will use a 4Kb stacksize for the Index: linux-2.6.18-rc6-mm1/arch/i386/kernel/irq.c =================================================================== --- linux-2.6.18-rc6-mm1.orig/arch/i386/kernel/irq.c +++ linux-2.6.18-rc6-mm1/arch/i386/kernel/irq.c @@ -83,6 +83,10 @@ fastcall unsigned int do_IRQ(struct pt_r } #endif + if (!irq_desc[irq].handle_irq) { + __do_IRQ(irq, regs); + goto out_exit; + } #ifdef CONFIG_4KSTACKS curctx = (union irq_ctx *) current_thread_info(); @@ -123,6 +127,7 @@ fastcall unsigned int do_IRQ(struct pt_r #endif desc->handle_irq(irq, desc, regs); +out_exit: irq_exit(); return 1; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.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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