Messages in this thread Patch in this message | | | From | Rusty Russell <> | Subject | Re: krealloc in kernel/params.c | Date | Fri, 17 Oct 2014 09:29:27 +1030 |
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Rasmus Villemoes <linux@rasmusvillemoes.dk> writes: > On Wed, Oct 15 2014, Rusty Russell <rusty@rustcorp.com.au> wrote: > >> Rasmus Villemoes <linux@rasmusvillemoes.dk> writes: >> The kzalloc-then-always-krealloc pattern is perhaps overly simplistic, >> but this code has clearly confused people. It worked on me... >> > > I think kzalloc immediately followed by kreallocing the returned value > is rather ugly. Other than that:
Indeed, but it's an obvious pattern. "If not initialized, initialize".
>> - num = mk->mp->num; >> - attrs = mk->mp->grp.attrs; >> + /* First allocation. */ >> + mk->mp = kzalloc(sizeof(*mk->mp), GFP_KERNEL); >> + if (!mk->mp) >> + return -ENOMEM; > > free_module_param_attrs does not check mk->mp for being NULL before > kfree'ing mk->mp->grp.attrs, so this will oops.
Nice catch, folded this in:
diff --git a/kernel/params.c b/kernel/params.c index 3ebe6c64aa67..ee92e67f2cee 100644 --- a/kernel/params.c +++ b/kernel/params.c @@ -650,7 +650,8 @@ static __modinit int add_sysfs_param(struct module_kobject *mk, #ifdef CONFIG_MODULES static void free_module_param_attrs(struct module_kobject *mk) { - kfree(mk->mp->grp.attrs); + if (mk->mp) + kfree(mk->mp->grp.attrs); kfree(mk->mp); mk->mp = NULL; } Thanks! Rusty.
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