3.0-stable review patch. If anyone has any objections, please let us know.
------------------
From: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
commit ed585a651681e822089087b426e6ebfb6d3d9873 upstream.
If an irq_chip provides .irq_shutdown(), but neither of .irq_disable() or
.irq_mask(), free_irq() crashes when jumping to NULL.
Fix this by only trying .irq_disable() and .irq_mask() if there's no
.irq_shutdown() provided.
This revives the symmetry with irq_startup(), which tries .irq_startup(),
.irq_enable(), and irq_unmask(), and makes it consistent with the comment for
irq_chip.irq_shutdown() in <linux/irq.h>, which says:
* @irq_shutdown: shut down the interrupt (defaults to ->disable if NULL)
This is also how __free_irq() behaved before the big overhaul, cfr. e.g.
3b56f0585fd4c02d047dc406668cb40159b2d340 ("genirq: Remove bogus conditional"),
where the core interrupt code always overrode .irq_shutdown() to
.irq_disable() if .irq_shutdown() was NULL.
Signed-off-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Cc: linux-m68k@xxxxxxxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/1315742394-16036-2-git-send-email-geert@xxxxxxxxxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
kernel/irq/chip.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -178,7 +178,7 @@ void irq_shutdown(struct irq_desc *desc)
desc->depth = 1;
if (desc->irq_data.chip->irq_shutdown)
desc->irq_data.chip->irq_shutdown(&desc->irq_data);
- if (desc->irq_data.chip->irq_disable)
+ else if (desc->irq_data.chip->irq_disable)
desc->irq_data.chip->irq_disable(&desc->irq_data);
else
desc->irq_data.chip->irq_mask(&desc->irq_data);
--
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