diff options
| author | Michael Ellerman <michael@ellerman.id.au> | 2007-06-19 08:08:00 +0200 |
|---|---|---|
| committer | Paul Mackerras <paulus@samba.org> | 2007-07-10 13:53:47 +0200 |
| commit | 6a281856c02d2291df2f7d9df5bfdee2e7bdd747 (patch) | |
| tree | f9dee0818d797edef6fdb59ddeb069883a7b191c | |
| parent | [POWERPC] Generalise device_node flag interface (diff) | |
| download | linux-6a281856c02d2291df2f7d9df5bfdee2e7bdd747.tar.xz linux-6a281856c02d2291df2f7d9df5bfdee2e7bdd747.zip | |
[POWERPC] Add a warning to help trackdown device_node refcounting bugs
When the refcount for a device node goes to 0, we call the
destructor - of_node_release(). This should only happen if we've
already detached the node from the device tree.
So add a flag OF_DETACHED which tracks detached-ness, and if we
find ourselves in of_node_release() without it set, issue a
warning and don't free the device_node. To avoid warning
continuously reinitialise the kref to a sane value.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
| -rw-r--r-- | arch/powerpc/kernel/prom.c | 11 | ||||
| -rw-r--r-- | include/asm-powerpc/prom.h | 1 |
2 files changed, 12 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c index bcd1c5ed44a3..6d5e601097a0 100644 --- a/arch/powerpc/kernel/prom.c +++ b/arch/powerpc/kernel/prom.c @@ -1375,8 +1375,17 @@ static void of_node_release(struct kref *kref) struct device_node *node = kref_to_device_node(kref); struct property *prop = node->properties; + /* We should never be releasing nodes that haven't been detached. */ + if (!of_node_check_flag(node, OF_DETACHED)) { + printk("WARNING: Bad of_node_put() on %s\n", node->full_name); + dump_stack(); + kref_init(&node->kref); + return; + } + if (!of_node_check_flag(node, OF_DYNAMIC)) return; + while (prop) { struct property *next = prop->next; kfree(prop->name); @@ -1457,6 +1466,8 @@ void of_detach_node(const struct device_node *np) prevsib->sibling = np->sibling; } + of_node_set_flag(np, OF_DETACHED); + out_unlock: write_unlock(&devtree_lock); } diff --git a/include/asm-powerpc/prom.h b/include/asm-powerpc/prom.h index f1006b91bd1a..1632baa17dc6 100644 --- a/include/asm-powerpc/prom.h +++ b/include/asm-powerpc/prom.h @@ -99,6 +99,7 @@ extern struct device_node *of_chosen; /* flag descriptions */ #define OF_DYNAMIC 1 /* node and properties were allocated via kmalloc */ +#define OF_DETACHED 2 /* node has been detached from the device tree */ static inline int of_node_check_flag(struct device_node *n, unsigned long flag) { |