Messages in this thread | | | Subject | Re: [PATCH v4 1/4] sysctl: Add register_sysctl_init() interface | From | Xiaoming Ni <> | Date | Fri, 29 May 2020 16:33:01 +0800 |
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On 2020/5/29 15:36, Luis Chamberlain wrote: > On Fri, May 29, 2020 at 03:27:22PM +0800, Xiaoming Ni wrote: >> On 2020/5/29 15:09, Luis Chamberlain wrote: >>> On Tue, May 19, 2020 at 11:31:08AM +0800, Xiaoming Ni wrote: >>>> --- a/kernel/sysctl.c >>>> +++ b/kernel/sysctl.c >>>> @@ -3358,6 +3358,25 @@ int __init sysctl_init(void) >>>> kmemleak_not_leak(hdr); >>>> return 0; >>>> } >>>> + >>>> +/* >>>> + * The sysctl interface is used to modify the interface value, >>>> + * but the feature interface has default values. Even if register_sysctl fails, >>>> + * the feature body function can also run. At the same time, malloc small >>>> + * fragment of memory during the system initialization phase, almost does >>>> + * not fail. Therefore, the function return is designed as void >>>> + */ >>> >>> Let's use kdoc while at it. Can you convert this to proper kdoc? >>> >> Sorry, I do n’t know the format requirements of Kdoc, can you give me some >> tips for writing? > > Sure, include/net/mac80211.h is a good example. > >>>> +void __init register_sysctl_init(const char *path, struct ctl_table *table, >>>> + const char *table_name) >>>> +{ >>>> + struct ctl_table_header *hdr = register_sysctl(path, table); >>>> + >>>> + if (unlikely(!hdr)) { >>>> + pr_err("failed when register_sysctl %s to %s\n", table_name, path); >>>> + return; >>> >>> table_name is only used for this, however we can easily just make >>> another _register_sysctl_init() helper first, and then use a macro >>> which will concatenate this to something useful if you want to print >>> a string. I see no point in the description for this, specially since >>> the way it was used was not to be descriptive, but instead just a name >>> followed by some underscore and something else. >>> >> Good idea, I will fix and send the patch to you as soon as possible > > No rush :) > >>>> + } >>>> + kmemleak_not_leak(hdr); >>> >>> Is it *wrong* to run kmemleak_not_leak() when hdr was not allocated? >>> If so, can you fix the sysctl __init call itself? >> I don't understand here, do you mean that register_sysctl_init () does not >> need to call kmemleak_not_leak (hdr), or does it mean to add check hdr >> before calling kmemleak_not_leak (hdr) in sysctl_init ()? > > I'm asking that the way you are adding it, you don't run > kmemleak_not_leak(hdr) if the hdr allocation filed. If that is > right then it seems that sysctl_init() might not be doing it > right. > > Can that code be shared somehow? > > Luis
void __ref kmemleak_not_leak(const void *ptr) { pr_debug("%s(0x%p)\n", __func__, ptr);
if (kmemleak_enabled && ptr && !IS_ERR(ptr)) make_gray_object((unsigned long)ptr); } EXPORT_SYMBOL(kmemleak_not_leak);
In the code of kmemleak_not_leak(), it is verified that the pointer is valid, so kmemleak_not_leak (NULL) will not be a problem. At the same time, there is no need to call kmemleak_not_leak() in the failed branch of register_sysctl_init().
Thanks Xiaoming Ni
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