From: Meelis Roos <mroos@xxxxxxxx>
Date: Tue, 28 Feb 2012 23:36:07 +0200 (EET)
>> Meelis, can you get your tree back into a state where the crash happens
>> and then add the following debugging patch and see what happens?
>
> Tried it, no obvious results in dmesg, except the crash is in a slightly
> different location.
Interesting, the corruption is a little bit different this time, yet similar
to the ones we saw previously:
> [ 0.000000] TPC: <strcmp+0x8/0x60>
...
> [ 0.000000] i0: 000000007fcf3c80 i1: fffff8007fcec480 i2: 0000000001010101 i3: 0000000080808080
> [ 0.000000] i4: fffff8007fcb8ccd i5: 0000000000028337 i6: 0000000000763231 i7: 0000000000606250
This is strcmp(0x000000007fcf3c80, 0xfffff8007fcec480), the first arg is
a bad pointer, somehow the top virtual address bits have been zero'd out.
It comes from dp->full_name, so something walked all over the beginning
of a device_node object.
Let's see if we can figure out anything else about the nature of the
corruption, please add this patch on top.
diff --git a/drivers/of/base.c b/drivers/of/base.c
index 133908a..7c0f7f4 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -376,6 +376,18 @@ struct device_node *of_find_node_by_path(const char *path)
read_lock(&devtree_lock);
for (; np; np = np->allnext) {
+ if (!np->full_name)
+ continue;
+
+ if ((unsigned long)np->full_name < 0xfffff80000000000) {
+ pr_info("OF BUG: Bogus full_name pointer [%p]\n",
+ np->full_name);
+ pr_info("OF BUG: np[%p] np->name[%p] np->type[%p] np->phandle[0x%08x]\n",
+ np, np->name, np->type, (unsigned int) np->phandle);
+ pr_info("OF BUG: np->name(%s) np->type(%s)\n",
+ np->name, np->type);
+ }
+
if (np->full_name && (of_node_cmp(np->full_name, path) == 0)
&& of_node_get(np))
break;
--
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