Messages in this thread | | | Date | Thu, 21 Oct 2004 10:12:15 +0200 | From | Ingo Molnar <> | Subject | Re: [patch] Real-Time Preemption, -RT-2.6.9-rc4-mm1-U8 |
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* Michal Schmidt <xschmi00@stud.feec.vutbr.cz> wrote:
> That patch was not enough. The BUGs were still showing up the same as > before. I tried to debug it myself. I've found an interesting thing in > kernel/printk.c:release_console_sem(). There is the following > sequence: > > spin_lock_irqsave(&logbuf_lock, flags); > /* ... some code ... */ > spin_unlock(&logbuf_lock); > call_console_drivers(...); > local_irq_restore(flags); > > I know very little about locking, but I didn't like this two-phased > unlock. So I replaced it with a single spin_unlock_irqrestore. Patch > attached. I'm almost certain that there is a reason for the two-phased > unlocking and that this patch will break something, but so far it > works for me. netconsole now works without complaining.
ah, indeed. Note that this is still not enough - please try to add a local_irq_enable() to netconsole.c's console-write function - does that fix it equally well for you?
the reason is that if we crash within an irqs-off section then netconsole will still be called with interrupts disabled and will trigger the assert.
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