From: John Hubbard <jhubbard@nvidia.com>
To: Kees Cook <keescook@chromium.org>, Vlastimil Babka <vbabka@suse.cz>
Cc: Luis Chamberlain <mcgrof@kernel.org>,
Iurii Zaikin <yzaikin@google.com>, <linux-kernel@vger.kernel.org>,
<linux-api@vger.kernel.org>, <linux-mm@kvack.org>,
Ivan Teterevkov <ivan.teterevkov@nutanix.com>,
Michal Hocko <mhocko@kernel.org>,
David Rientjes <rientjes@google.com>,
Matthew Wilcox <willy@infradead.org>,
"Eric W . Biederman" <ebiederm@xmission.com>,
"Guilherme G . Piccoli" <gpiccoli@canonical.com>,
Alexey Dobriyan <adobriyan@gmail.com>,
Thomas Gleixner <tglx@linutronix.de>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Christian Brauner <christian.brauner@ubuntu.com>
Subject: Re: [PATCH 3/3] kernel/hung_task convert hung_task_panic boot parameter to sysctl
Date: Mon, 30 Mar 2020 17:34:15 -0700 [thread overview]
Message-ID: <13ae67d8-4b31-db20-7ba4-1602906a291e@nvidia.com> (raw)
In-Reply-To: <202003301042.97F3B00@keescook>
On 3/30/20 10:43 AM, Kees Cook wrote:
...
>> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
>> index 81ff626fc700..e0b8840404a1 100644
>> --- a/Documentation/admin-guide/kernel-parameters.txt
>> +++ b/Documentation/admin-guide/kernel-parameters.txt
>> @@ -1457,7 +1457,7 @@
>> [KNL] Should the hung task detector generate panics.
>> Format: <integer>
>>
>> - A nonzero value instructs the kernel to panic when a
>> + A value of 1 instructs the kernel to panic when a
>> hung task is detected. The default value is controlled
>> by the CONFIG_BOOTPARAM_HUNG_TASK_PANIC build-time
>> option. The value selected by this boot parameter can
>> diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
>> index 97eb0b552bf8..77b1b844b02b 100644
>> --- a/fs/proc/proc_sysctl.c
>> +++ b/fs/proc/proc_sysctl.c
>> @@ -1743,6 +1743,7 @@ struct sysctl_alias {
>> */
>> static const struct sysctl_alias sysctl_aliases[] = {
>> {"numa_zonelist_order", "vm.numa_zonelist_order" },
Hi Vlastimil,
Maybe best to delete the above line? Because:
a) it was added as an example, and now that you have a real use case in this patch,
the example is no longer required, and
b) numa_zonelist_order is deprecated, as a boot param. Adding support to it in this
brand-new mechanism seems to be going a bit in the opposite direction of deprecation.
And, I don't think you really want all the sysctls to be enabled as boot params, right? Your
comment right above sysctl_aliases[] (shown in patch 2) sort of indicates that only some items
are meant to be both sysctl's and boot params. And that makes sense.
In fact, the sysctl_aliases[] is (or could be) effectively the whitelist that Luis Chamberlain
was requesting in another thread. A whitelist makes good sense, for the reasons Luis listed.
As such, keeping it limited to items that we want, seems like the way to go, IMHO.
thanks,
--
John Hubbard
NVIDIA
>> + {"hung_task_panic", "kernel.hung_task_panic" },
>> { }
>> };
>>
>> diff --git a/kernel/hung_task.c b/kernel/hung_task.c
>> index 14a625c16cb3..b22b5eeab3cb 100644
>> --- a/kernel/hung_task.c
>> +++ b/kernel/hung_task.c
>> @@ -63,16 +63,6 @@ static struct task_struct *watchdog_task;
>> unsigned int __read_mostly sysctl_hung_task_panic =
>> CONFIG_BOOTPARAM_HUNG_TASK_PANIC_VALUE;
>>
>> -static int __init hung_task_panic_setup(char *str)
>> -{
>> - int rc = kstrtouint(str, 0, &sysctl_hung_task_panic);
>> -
>> - if (rc)
>> - return rc;
>> - return 1;
>> -}
>> -__setup("hung_task_panic=", hung_task_panic_setup);
>> -
>> static int
>> hung_task_panic(struct notifier_block *this, unsigned long event, void *ptr)
>> {
>> --
>> 2.25.1
>>
>
next prev parent reply other threads:[~2020-03-31 0:34 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-30 11:55 [PATCH 0/3] support setting sysctl parameters from kernel command line Vlastimil Babka
2020-03-30 11:55 ` [PATCH 1/3] kernel/sysctl: " Vlastimil Babka
2020-03-30 16:23 ` Vlastimil Babka
2020-03-30 17:40 ` Kees Cook
2020-03-30 17:39 ` Kees Cook
2020-03-30 22:44 ` Luis Chamberlain
2020-03-31 7:42 ` Vlastimil Babka
2020-03-31 7:48 ` Michal Hocko
2020-03-31 18:26 ` Kees Cook
2020-03-31 14:31 ` Luis Chamberlain
2020-04-01 11:01 ` Vlastimil Babka
2020-04-02 16:04 ` Luis Chamberlain
2020-04-02 17:23 ` Kees Cook
2020-04-02 20:59 ` Luis Chamberlain
2020-04-03 23:57 ` Kees Cook
2020-04-06 14:08 ` Luis Chamberlain
2020-04-06 15:58 ` Kees Cook
2020-04-06 17:08 ` Luis Chamberlain
2020-04-14 11:25 ` Vlastimil Babka
2020-04-15 3:23 ` Masami Hiramatsu
2020-04-15 6:08 ` Luis Chamberlain
2020-03-30 11:55 ` [PATCH 2/3] kernel/sysctl: support handling command line aliases Vlastimil Babka
2020-03-30 17:41 ` Kees Cook
2020-03-31 14:35 ` Luis Chamberlain
2020-03-30 11:55 ` [PATCH 3/3] kernel/hung_task convert hung_task_panic boot parameter to sysctl Vlastimil Babka
2020-03-30 17:43 ` Kees Cook
2020-03-31 0:34 ` John Hubbard [this message]
2020-03-31 7:27 ` Vlastimil Babka
2020-03-31 15:49 ` John Hubbard
2020-03-31 23:12 ` Tetsuo Handa
2020-04-01 8:47 ` Vlastimil Babka
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