Re: two 2.5 modules bugs

From: Rusty Russell (rusty@rustcorp.com.au)
Date: Sat Dec 28 2002 - 05:37:22 EST

In message <200212271616.RAA03356@harpo.it.uu.se> you write:
> 1. With kernel 2.5.53 and module-init-tools-0.9.6, "modprobe tulip"
> fails and goes into an infinite CPU-consuming loop. The problem
> appears to be related to the dependency from tulip to crc32. If I
> manually modprobe crc32 before modprobe tulip, it works. If crc32
> isn't loaded, modprobe tulip first loads crc32 and then loops.
>
> module-init-tools-0.9.5 did not have this problem.

This should be fixed in 0.9.6: a double free caused all kinds of wierd
behavior. Please tell me if this fixes it.

> 2. The implementation of old-style MODULE_PARMs with type "1-16s"
> is broken. Instead of splicing the parameter at the commas and
> storing pointers to the substrings in consecutive array elements,
> the whole string is stored in the array instead.
>
> Consider parport_pc.c, which contains (simplified):
>
> static const char *irq[16];
> MODULE_PARM(irq, "1-16s");
>
> "modprobe parport_pc irq=007" should store a pointer to "007" in
> irq[0], but instead (unsigned int)irq[0] == 0x00373030, the ASCII
> representation of "007" in little-endian. (Kernel 2.5.53 on x86,
> with module-init-tools-0.9.[56].)

Ew. I horribly misinterpreted "1-16s" to mean "a string 1-16 chars
long". The obvious fix (untested) is:

diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal linux-2.5.53/kernel/module.c working-2.5.53-sparam/kernel/module.c
--- linux-2.5.53/kernel/module.c 2002-12-26 15:41:06.000000000 +1100
+++ working-2.5.53-sparam/kernel/module.c 2002-12-28 21:32:34.000000000 +1100
@@ -604,7 +604,8 @@ extern int set_obsolete(const char *val,
                 return param_array(kp->name, val, min, max, obsparm->addr,
                                    sizeof(long), param_set_long);
         case 's':
- return param_string(kp->name, val, min, max, obsparm->addr);
+ return param_array(kp->name, val, min, max, obsparm->addr,
+ sizeof(char *), param_set_charp);
         }
         printk(KERN_ERR "Unknown obsolete parameter type %s\n", obsparm->type);
         return -EINVAL;

I'll test this tomorrow...

Thanks for the bug report!
Rusty. 

--
  Anyone who quotes me in their sig is an idiot. -- Rusty Russell.
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