x86/i8259: Use printk_deferred() to prevent deadlock
commit bdd6558959
upstream.
0day reported a possible circular locking dependency:
Chain exists of:
&irq_desc_lock_class --> console_owner --> &port_lock_key
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&port_lock_key);
lock(console_owner);
lock(&port_lock_key);
lock(&irq_desc_lock_class);
The reason for this is a printk() in the i8259 interrupt chip driver
which is invoked with the irq descriptor lock held, which reverses the
lock operations vs. printk() from arbitrary contexts.
Switch the printk() to printk_deferred() to avoid that.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/87365abt2v.fsf@nanos.tec.linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
5.4-rM2-2.2.x-imx-squashed
parent
01ac46c6ba
commit
3956854670
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@ -207,7 +207,7 @@ spurious_8259A_irq:
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* lets ACK and report it. [once per IRQ]
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*/
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if (!(spurious_irq_mask & irqmask)) {
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printk(KERN_DEBUG
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printk_deferred(KERN_DEBUG
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"spurious 8259A interrupt: IRQ%d.\n", irq);
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spurious_irq_mask |= irqmask;
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}
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