[PATCH] ARM: 2694/1: [s3c2410/dma] release irq properly to fix kernel oops
Patch from Albrecht Dreß
Problem:
When a module requests a DMA channel via the function s3c2410_dma_request(), this function requests the appropriate irq under the name of the client module. When the client module is unloaded, it calls s3c2410_dma_free() which does not free the irq. Consequently, when e.g. running "cat /proc/interrupts", the irq owner points to freed memory, leading to a kernel oops.
File:
linux/arch/arm/mach-s3c2410/dma.c
Fix:
trivial, below
Signed-off-by: Albrecht Dreß
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mach-s3c2410/dma.c b/arch/arm/mach-s3c2410/dma.c
index bc229fa..c7c2889 100644
--- a/arch/arm/mach-s3c2410/dma.c
+++ b/arch/arm/mach-s3c2410/dma.c
@@ -785,6 +785,10 @@
chan->client = NULL;
chan->in_use = 0;
+ if (chan->irq_claimed)
+ free_irq(chan->irq, (void *)chan);
+ chan->irq_claimed = 0;
+
local_irq_restore(flags);
return 0;