Ok, I don't want to remember how many times I've gotten burned by the
dev_printk() function while developing drivers, as it doesn't check for
valid pointers before dereferencing them. So here's a patch I've
started using that might help out any kernel driver developers in the
same situation. For device busses that support hotplug, this patch is a
lifesaver (the dev->driver pointer has a fun habit of going away pretty
early during disconnect...)
I'm not pushing for submission to the main kernel tree, unless others
really feel it's useful.
greg k-h
# added CONFIG_DEBUG_DEV_PRINTK option to keep my sanity during development.
diff -Nru a/arch/i386/Kconfig b/arch/i386/Kconfig
--- a/arch/i386/Kconfig Mon Apr 14 11:46:36 2003
+++ b/arch/i386/Kconfig Mon Apr 14 11:46:36 2003
@@ -1504,6 +1504,13 @@
This options enables addition error checking for high memory systems.
Disable for production systems.
+config DEBUG_DEV_PRINTK
+ bool "Debug dev_printk"
+ depends on DEBUG_KERNEL
+ help
+ If you say Y here, all dev_printk() parameters will be checked before
+ dev_printk() is called. This is useful when debugging new drivers.
+
config KALLSYMS
bool "Load all symbols for debugging/kksymoops"
help
diff -Nru a/include/linux/device.h b/include/linux/device.h
--- a/include/linux/device.h Mon Apr 14 11:46:36 2003
+++ b/include/linux/device.h Mon Apr 14 11:46:36 2003
@@ -379,8 +379,20 @@
extern void firmware_unregister(struct subsystem *);
/* debugging and troubleshooting/diagnostic helpers. */
+#ifdef CONFIG_DEBUG_DEV_PRINTK
+#define dev_printk(level, dev, format, arg...) \
+ do { \
+ if (!(dev) || !(dev)->driver) \
+ WARN_ON(1); \
+ else \
+ printk(level "%s %s: " format , \
+ (dev)->driver->name , \
+ (dev)->bus_id , ## arg); \
+ } while (0)
+#else
#define dev_printk(level, dev, format, arg...) \
printk(level "%s %s: " format , (dev)->driver->name , (dev)->bus_id , ## arg)
+#endif
#ifdef DEBUG
#define dev_dbg(dev, format, arg...) \
-
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This archive was generated by hypermail 2b29 : Tue Apr 15 2003 - 22:00:35 EST