From 064aced595bf067cd6fb86a2260e3ac4f6960ec1 Mon Sep 17 00:00:00 2001 From: Dave Hansen Date: Thu, 16 Mar 2006 17:30:16 -0800 Subject: warn when statically-allocated kobjects are used One of the top ten sysfs problems is that users use statically allocated kobjects. This patch reminds them that this is a naughty thing. One _really_ nice thing this patch does, is us the kallsyms mechanism to print out exactly which symbol is being complained about: The kobject at, or inside 'statickobj.2'@(0xc040d020) is not dynamically allocated. This patch replaces the previous implementation's use of a _sdata symbol in favor of using kallsyms_lookup(). If a kobject's address is a resolvable symbol, then it isn't dynamically allocated. The one exception to this is init symbols. The patch also checks to see whether __init memory has been freed and if it has will allow kobjects in those sections. Signed-off-by: Dave Hansen Signed-off-by: Greg Kroah-Hartman --- lib/kobject.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) (limited to 'lib') diff --git a/lib/kobject.c b/lib/kobject.c index fa8ef86a072d..829b83915626 100644 --- a/lib/kobject.c +++ b/lib/kobject.c @@ -17,6 +17,57 @@ #include #include #include +#include +#include + +#ifdef CONFIG_X86_32 +static int ptr_in_range(void *ptr, void *start, void *end) +{ + /* + * This should hopefully get rid of causing warnings + * if the architecture did not set one of the section + * variables up. + */ + if (start >= end) + return 0; + + if ((ptr >= start) && (ptr < end)) + return 1; + return 0; +} + +static void verify_dynamic_kobject_allocation(struct kobject *kobj) +{ + char *namebuf; + const char *ret; + + namebuf = kzalloc(KSYM_NAME_LEN, GFP_KERNEL); + ret = kallsyms_lookup((unsigned long)kobj, NULL, NULL, NULL, + namebuf); + /* + * This is the X86_32-only part of this function. + * This is here because it is valid to have a kobject + * in an __init section, but only after those + * sections have been freed back to the dynamic pool. + */ + if (!initmem_now_dynamic && + ptr_in_range(kobj, __init_begin, __init_end)) + goto out; + if (!ret || !strlen(ret)) + goto out; + pr_debug("---- begin silly warning ----\n"); + pr_debug("This is a janitorial warning, not a kernel bug.\n"); + pr_debug("The kobject '%s', at, or inside '%s'@(0x%p) is not " + "dynamically allocated.\n", kobject_name(kobj), namebuf, kobj); + pr_debug("kobjects must be dynamically allocated, not static\n"); + /* dump_stack(); */ + pr_debug("---- end silly warning ----\n"); +out: + kfree(namebuf); +} +#else +static void verify_dynamic_kobject_allocation(struct kobject *kobj) { } +#endif /* * populate_dir - populate directory with attributes. @@ -284,6 +335,7 @@ void kobject_init(struct kobject *kobj, struct kobj_type *ktype) "object, something is seriously wrong.\n", kobj); dump_stack(); } + verify_dynamic_kobject_allocation(kobj); kobject_init_internal(kobj); kobj->ktype = ktype; -- cgit v1.2.3