"Jean Delvare" <khali at linux-fr.org> wrote: > > > Hi Andrew, > > > > >>EIP; c02f094f <i2c_detect+f/500> <===== > > > > > > >>ebx; f7c076fc <pg0+376a46fc/3fa9b400> > > > >>edx; f7c07558 <pg0+376a4558/3fa9b400> > > > >>esi; c047c8e0 <eeprom_driver+0/e0> > > > > > > Trace; c0104d7f <show_stack+7f/a0> > > > Trace; c0104f1a <show_registers+15a/1c0> > > > Trace; c0105184 <die+164/2e0> > > > Trace; c0119936 <do_page_fault+356/68d> > > > Trace; c0104853 <error_code+4f/54> > > > Trace; c02f1aa1 <eeprom_attach_adapter+21/30> > > > Trace; c02ee704 <i2c_add_driver+b4/e0> > > > Trace; c050a652 <eeprom_init+12/40> > > > Trace; c04ee8ab <do_initcalls+2b/c0> > > > Trace; c0100302 <init+32/130> > > > Trace; c0101351 <kernel_thread_helper+5/14> > > > > Ah. adapter->algo is NULL in i2c_detect(). > > Forgive a possibly stupid question, but how did you manage to come to > this conclusion from the stack above alone? Is there any magic I am not > aware of? Well it oopsed at one of the first statements in i2c_detect(), and the faulting address was 0x00000020. And the offset of i2c_algorithm.id is 32. So adapter->algo is NULL in i2c_is_isa_adapter(). > My first impression was that the adapter itself was missing, like it had > been deleted without being removed from the main i2c adapters list. > > Anyway, this test at leasted proved one thing: the i2c-dev driver isn't > involved in the oops per se. Using a different i2c chip driver (eeprom > here) triggers it as well. This tends to confirm that the problem is > related to a specific i2c adapter driver. I'd say so. > > I don't think i2c_adapters are allowed to do that. > > Correct, they are not. > > > It could have been any old adapter, registered at some earlier time. > > Except that we have a strong suspicion that it is nvidiafb, instead of > just any old adapter. Could be. > > If I'm right, this debug patch should point us at the culprit. > > I doubt it will help (but let's still try). The nvidiafb i2c adapters > are added by i2c-algo-bit:i2c_bit_add_bus(), which does set > adapter->algo to &i2c_bit_algo right before it calls i2c_add_adapter. I > don't think that algo is NULL when the adapter is added. Rather, it > becomes NULL later, most possibly because adapter itself point to a now > gone structure. Just my theory though. urgh. That explains why the patch didn't work. Miles, there's a new debug patch below. > Maybe it would help if Miles could give a try to Tony's patch here and > report? > http://archives.andrew.net.au/lm-sensors/msg30044.html That too. 25-akpm/drivers/i2c/algos/i2c-algo-bit.c | 6 ++++-- 25-akpm/drivers/i2c/i2c-core.c | 12 ++++++++++-- 25-akpm/include/linux/i2c-algo-bit.h | 3 ++- 25-akpm/include/linux/i2c.h | 6 +++++- 4 files changed, 21 insertions(+), 6 deletions(-) diff -puN include/linux/i2c.h~i2c-debugging include/linux/i2c.h --- 25/include/linux/i2c.h~i2c-debugging 2005-03-22 02:02:53.000000000 -0800 +++ 25-akpm/include/linux/i2c.h 2005-03-22 02:06:50.000000000 -0800 @@ -244,6 +244,8 @@ struct i2c_adapter { char name[I2C_NAME_SIZE]; struct completion dev_released; struct completion class_dev_released; + char *file; + int line; }; #define dev_to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev) #define class_dev_to_i2c_adapter(d) container_of(d, struct i2c_adapter, class_dev) @@ -314,7 +316,9 @@ struct i2c_client_address_data { /* administration... */ -extern int i2c_add_adapter(struct i2c_adapter *); +#define i2c_add_adapter(a) __i2c_add_adapter(__FILE__, __LINE__, a) + +extern int __i2c_add_adapter(char *file, int line, struct i2c_adapter *); extern int i2c_del_adapter(struct i2c_adapter *); extern int i2c_add_driver(struct i2c_driver *); diff -puN drivers/i2c/i2c-core.c~i2c-debugging drivers/i2c/i2c-core.c --- 25/drivers/i2c/i2c-core.c~i2c-debugging 2005-03-22 02:02:53.000000000 -0800 +++ 25-akpm/drivers/i2c/i2c-core.c 2005-03-22 02:02:53.000000000 -0800 @@ -144,12 +144,15 @@ static struct device_attribute dev_attr_ * when a new hw adapter registers. A new device is register to be * available for clients. */ -int i2c_add_adapter(struct i2c_adapter *adap) +int __i2c_add_adapter(char *file, int line, struct i2c_adapter *adap) { int id, res = 0; struct list_head *item; struct i2c_driver *driver; + adap->file = file; + adap->line = line; + down(&core_lists); if (idr_pre_get(&i2c_adapter_idr, GFP_KERNEL) == 0) { @@ -310,6 +313,11 @@ int i2c_add_driver(struct i2c_driver *dr if (driver->flags & I2C_DF_NOTIFY) { list_for_each(item,&adapters) { adapter = list_entry(item, struct i2c_adapter, list); + printk("%s:%d: %p\n", adapter->file, adapter->line, + adapter->algo); + if (adapter->algo == NULL) + for ( ; ; ) + ; driver->attach_adapter(adapter); } } @@ -1246,7 +1254,7 @@ int i2c_check_functionality (struct i2c_ return (func & adap_func) == func; } -EXPORT_SYMBOL(i2c_add_adapter); +EXPORT_SYMBOL(__i2c_add_adapter); EXPORT_SYMBOL(i2c_del_adapter); EXPORT_SYMBOL(i2c_add_driver); EXPORT_SYMBOL(i2c_del_driver); diff -puN drivers/i2c/algos/i2c-algo-bit.c~i2c-debugging drivers/i2c/algos/i2c-algo-bit.c --- 25/drivers/i2c/algos/i2c-algo-bit.c~i2c-debugging 2005-03-22 02:03:15.000000000 -0800 +++ 25-akpm/drivers/i2c/algos/i2c-algo-bit.c 2005-03-22 02:04:31.000000000 -0800 @@ -528,10 +528,12 @@ static struct i2c_algorithm i2c_bit_algo /* * registering functions to load algorithms at runtime */ -int i2c_bit_add_bus(struct i2c_adapter *adap) +int __i2c_bit_add_bus(char *file, int line, struct i2c_adapter *adap) { struct i2c_algo_bit_data *bit_adap = adap->algo_data; + adap->file = file; + adap->line = line; if (bit_test) { int ret = test_bus(bit_adap, adap->name); if (ret<0) @@ -558,7 +560,7 @@ int i2c_bit_del_bus(struct i2c_adapter * return i2c_del_adapter(adap); } -EXPORT_SYMBOL(i2c_bit_add_bus); +EXPORT_SYMBOL(__i2c_bit_add_bus); EXPORT_SYMBOL(i2c_bit_del_bus); MODULE_AUTHOR("Simon G. Vogl <simon at tk.uni-linz.ac.at>"); diff -puN include/linux/i2c-algo-bit.h~i2c-debugging include/linux/i2c-algo-bit.h --- 25/include/linux/i2c-algo-bit.h~i2c-debugging 2005-03-22 02:03:33.000000000 -0800 +++ 25-akpm/include/linux/i2c-algo-bit.h 2005-03-22 02:05:08.000000000 -0800 @@ -48,7 +48,8 @@ struct i2c_algo_bit_data { #define I2C_BIT_ADAP_MAX 16 -int i2c_bit_add_bus(struct i2c_adapter *); +#define i2c_bit_add_bus(a) __i2c_bit_add_bus(__FILE__, __LINE__, a) +int __i2c_bit_add_bus(char *file, int line, struct i2c_adapter *); int i2c_bit_del_bus(struct i2c_adapter *); #endif /* _LINUX_I2C_ALGO_BIT_H */ _
