diff options
author | Dave Hansen <haveblue@us.ibm.com> | 2006-03-16 17:30:16 -0800 |
---|---|---|
committer | Stephen Rothwell <sfr@canb.auug.org.au> | 2008-11-03 09:34:12 +1100 |
commit | 878f10229662bedeca043904ee1bb1a36c1a4266 (patch) | |
tree | 559ca115d4a00d9544c1da12fe554a0a05bb059e | |
parent | 18f6fb62fdc0617707b1857c1105d996dd57eb34 (diff) |
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 <haveblue@us.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r-- | include/linux/init.h | 1 | ||||
-rw-r--r-- | init/main.c | 9 | ||||
-rw-r--r-- | lib/kobject.c | 50 |
3 files changed, 60 insertions, 0 deletions
diff --git a/include/linux/init.h b/include/linux/init.h index 68cb0265d009..0eb83c92805c 100644 --- a/include/linux/init.h +++ b/include/linux/init.h @@ -147,6 +147,7 @@ extern int do_one_initcall(initcall_t fn); extern char __initdata boot_command_line[]; extern char *saved_command_line; extern unsigned int reset_devices; +extern int initmem_now_dynamic; /* used by init/main.c */ void setup_arch(char **); diff --git a/init/main.c b/init/main.c index 7e117a231af1..f09354167789 100644 --- a/init/main.c +++ b/init/main.c @@ -789,12 +789,21 @@ static void run_init_process(char *init_filename) kernel_execve(init_filename, argv_init, envp_init); } +/* + * __init/__init_data sections are turned into normal + * dynamically allocated memory later in boot. When + * this is 0, the memory is for the __init purposes, + * when it it some other value, the memory is dynamic. + */ +int initmem_now_dynamic; + /* This is a non __init function. Force it to be noinline otherwise gcc * makes it inline to init() and it becomes part of init.text section */ static int noinline init_post(void) { free_initmem(); + initmem_now_dynamic = 1; unlock_kernel(); mark_rodata_ro(); system_state = SYSTEM_RUNNING; diff --git a/lib/kobject.c b/lib/kobject.c index 0487d1f64806..2fded6d8ca54 100644 --- a/lib/kobject.c +++ b/lib/kobject.c @@ -17,6 +17,55 @@ #include <linux/module.h> #include <linux/stat.h> #include <linux/slab.h> +#include <linux/kallsyms.h> +#include <asm-generic/sections.h> + +#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[KSYM_NAME_LEN]; + const char *ret; + + 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: + return; +} +#else +static void verify_dynamic_kobject_allocation(struct kobject *kobj) { } +#endif /* * populate_dir - populate directory with attributes. @@ -282,6 +331,7 @@ 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; |